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Search for "HIV-1" in Full Text gives 62 result(s) in Beilstein Journal of Organic Chemistry.
A selective removal of the secondary hydroxy group from ortho-dithioacetal-substituted diarylmethanols
- Anna Czarnecka,
- Emilia Kowalska,
- Agnieszka Bodzioch,
- Joanna Skalik,
- Marek Koprowski,
- Krzysztof Owsianik and
- Piotr Bałczewski
Beilstein J. Org. Chem. 2018, 14, 1229–1237, doi:10.3762/bjoc.14.105
- ] or vasodilating activities (II) [6]. Other ones have been reported as inhibitors of HIV-1 integrase and viral replication in cells [7] or antitubercular agents (III) [8][9]. Various diarylmethane-based molecules, like tolterodine (IV) [10], podophyllotoxin (V) [11] and lasofoxifene (VI) [12] have
Graphical Abstract
Figure 1: Structures of biologically active diarylmethanes and commercially available pharmaceuticals based o...
Scheme 1: Various synthetic approaches to diarylmethanols (literature review and this work).
Scheme 2: A general strategy for the synthesis of ortho-1,3-dithianylaryl(aryl)methanols 5 and 6, and their r...
Scheme 3: Attempts of the OH removal in ortho-1,3-dithianyl- 6b and ortho-1,3-dioxanylaryl(aryl)methanols 9 u...
An overview of recent advances in duplex DNA recognition by small molecules
- Sayantan Bhaduri,
- Nihar Ranjan and
- Dev P. Arya
Beilstein J. Org. Chem. 2018, 14, 1051–1086, doi:10.3762/bjoc.14.93
- ]. Gottesfeld et al. synthesized a series of Py/Im HP-polyamide–DNA alkylator (chlorambucil) (HP-Chl) conjugates in order to bind and alkylate within the HIV-1 promoter region, thereby blocking HIV-1 replication and screened them against human colon carcinoma cell lines [74][75]. It has been observed that
Graphical Abstract
Figure 1: A figure showing the hydrogen bonding patterns observed in (a) duplex (b) triplex and (c) quadruple...
Figure 2: (a) Portions of MATα1–MATα2 are shown contacting the minor groove of the DNA substrate. Key arginin...
Figure 3: Chemical structures of naturally occurring and synthetic hybrid minor groove binders.
Figure 4: Synthetic structural analogs of distamycin A by replacing one or more pyrrole rings with other hete...
Figure 5: Pictorial representation of the binding model of pyrrole–imidazole (Py/Im) polyamides based on the ...
Figure 6: Chemical structures of synthetic “hairpin” pyrrole–imidazole (Py/Im) conjugates.
Figure 7: (a) Minor groove complex formation between DNA duplex and 8-ring cyclic Py/Im polyamide (conjugate ...
Figure 8: Telomere-targeting tandem hairpin Py/Im polyamides 23 and 24 capable of recognizing >10 base pairs; ...
Figure 9: Representative examples of recently developed DNA minor groove binders.
Figure 10: Chemical structures of bisbenzamidazoles Hoechst 33258 and 33342 and their synthetic structural ana...
Figure 11: Chemical structures of bisamidines such as diminazene, DAPI, pentamidine and their synthetic struct...
Figure 12: Representative examples of recently developed bisamidine derivatives.
Figure 13: Chemical structures of chromomycin, mithramycin and their synthetic structural analogs 91 and 92.
Figure 14: Chemical structures of well-known naturally occurring DNA binding intercalators.
Figure 15: Naturally occurring indolocarbazole rebeccamycin and its synthetic analogs.
Figure 16: Representative examples of naturally occurring and synthetic derivatives of DNA intercalating agent...
Figure 17: Several recent synthetic varieties of DNA intercalators.
Figure 18: Aminoglycoside (neomycin)–Hoechst 33258/intercalator conjugates.
Figure 19: Chemical structures of triazole linked neomycin dimers and neomycin–bisbenzimidazole conjugates.
Figure 20: Representative examples of naturally occurring and synthetic analogs of DNA binding alkylating agen...
Figure 21: Chemical structures of naturally occurring and synthetic analogs of pyrrolobenzodiazepines.
5-Aminopyrazole as precursor in design and synthesis of fused pyrazoloazines
- Ranjana Aggarwal and
- Suresh Kumar
Beilstein J. Org. Chem. 2018, 14, 203–242, doi:10.3762/bjoc.14.15
- -aminopyrazolo[1,5-a]pyrimidine derivatives 155 (Scheme 43). All the synthesized compounds were screened for their anti-HIV activities in MT4 cell cultures and compound 155 (R1 = 2,4,6-trimethyl and R2 = 4-cyano) was found as most inhibiting for HIV-1 replication having an EC50 = 0.070 μM and the SI (selectivity
Graphical Abstract
Figure 1: Selected examples of drugs with fused pyrazole rings.
Figure 2: Typical structures of some fused pyrazoloazines from 5-aminopyrazoles.
Scheme 1: Regiospecific synthesis of 4 and 6-trifluoromethyl-1H-pyrazolo[3,4-b]pyridines.
Scheme 2: Synthesis of pyrazolo[3,4-b]pyridine-6-carboxylates.
Scheme 3: Synthesis of 1,4,6-triaryl-1H-pyrazolo[3,4-b]pyridines with ionic liquid .
Scheme 4: Synthesis of coumarin-based isomeric tetracyclic pyrazolo[3,4-b]pyridines.
Scheme 5: Synthesis of 6-substituted pyrazolo[3,4-b]pyridines under Heck conditions.
Scheme 6: Microwave-assisted palladium-catalyzed synthesis of pyrazolo[3,4-b]pyridines.
Scheme 7: Acid-catalyzed synthesis of pyrazolo[3,4-b]pyridines via enaminones.
Scheme 8: Synthesis of pyrazolo[3,4-b]pyridines via aza-Diels–Alder reaction.
Scheme 9: Synthesis of macrocyclane fused pyrazolo[3,4-b]pyridine derivatives.
Scheme 10: Three-component synthesis of 4,7-dihydro-1H-pyrazolo[3,4-b]pyridine derivatives.
Scheme 11: Ultrasonicated synthesis of spiro[indoline-3,4'-pyrazolo[3,4-b]pyridine]-2,6'(1'H)-diones.
Scheme 12: Synthesis of spiro[indoline-3,4'-pyrazolo[3,4-b]pyridine] derivatives under conventional heating co...
Scheme 13: Nanoparticle-catalyzed synthesis of pyrazolo[3,4-b]pyridine-spiroindolinones.
Scheme 14: Microwave-assisted multicomponent synthesis of spiropyrazolo[3,4-b]pyridines.
Scheme 15: Unexpected synthesis of naphthoic acid-substituted pyrazolo[3,4-b]pyridines.
Scheme 16: Multicomponent synthesis of variously substituted pyrazolo[3,4-b]pyridine derivatives.
Scheme 17: Three-component synthesis of 4,7-dihydropyrazolo[3,4-b]pyridines and pyrazolo[3,4-b]pyridines.
Scheme 18: Synthesis of pyrazolo[3,4-b]pyridine-5-spirocycloalkanediones.
Scheme 19: Ultrasound-mediated three-component synthesis of pyrazolo[3,4-b]pyridines.
Scheme 20: Multicomponent synthesis of 4-aryl-3-methyl-1-phenyl-4,6,8,9-tetrahydropyrazolo [3,4-b]thiopyrano[4...
Scheme 21: Synthesis of 2,3-dihydrochromeno[4,3-d]pyrazolo[3,4-b]pyridine-1,6-diones.
Scheme 22: FeCl3-catalyzed synthesis of o-hydroxyphenylpyrazolo[3,4-b]pyridine derivatives.
Scheme 23: Ionic liquid-mediated synthesis of pyrazolo[3,4-b]pyridines.
Scheme 24: Microwave-assisted synthesis of pyrazolo[3,4-b]pyridines.
Scheme 25: Multicomponent synthesis of pyrazolo[3,4-b]pyridine-5-carbonitriles.
Scheme 26: Unusual domino synthesis of 4,7-dihydropyrazolo[3,4-b]pyridine-5-nitriles.
Scheme 27: Synthesis of 4,5,6,7-tetrahydro-4H-pyrazolo[3,4-b]pyridines under conventional heating and ultrasou...
Scheme 28: L-Proline-catalyzed synthesis of of pyrazolo[3,4-b]pyridine.
Scheme 29: Microwave-assisted synthesis of 5-aminoarylpyrazolo[3,4-b]pyridines.
Scheme 30: Microwave-assisted multi-component synthesis of pyrazolo[3,4-e]indolizines.
Scheme 31: Synthesis of fluoropropynyl and fluoroalkyl substituted pyrazolo[1,5-a]pyrimidine.
Scheme 32: Acid-catalyzed synthesis of pyrazolo[1,5-a]pyrimidine derivatives.
Scheme 33: Chemoselective and regiospecific synthesis of 2-(3-methylpyrazol-1’-yl)-5-methylpyrazolo[1,5-a]pyri...
Scheme 34: Regioselective synthesis of 7-trifluoromethylpyrazolo[1,5-a]pyrimidines.
Scheme 35: Microwave-assisted synthesis of 7-trifluoromethylpyrazolo[1,5-a]pyrimidine carboxylates.
Scheme 36: Microwave and ultrasound-assisted synthesis of 7-trifluoromethylpyrazolo[1,5-a]pyrimidines.
Scheme 37: Base-catalyzed unprecedented synthesis of pyrazolo[1,5-a]pyrimidines via C–C bond cleavage.
Scheme 38: Synthesis of aminobenzothiazole/piperazine linked pyrazolo[1,5-a]pyrimidines.
Scheme 39: Synthesis of aminoalkylpyrazolo[1,5-a]pyrimidine-7-amines.
Scheme 40: Synthesis of pyrazolo[1,5-a]pyrimidines from condensation of 5-aminopyrazole 126 and ethyl acetoace...
Scheme 41: Synthesis of 7-aminopyrazolo[1,5-a]pyrimidines.
Scheme 42: Unexpected synthesis of 7-aminopyrazolo[1,5-a]pyrimidines under solvent free and solvent-mediated c...
Scheme 43: Synthesis of N-(4-aminophenyl)-7-aryloxypyrazolo[1,5-a]pyrimidin-5-amines.
Scheme 44: Base-catalyzed synthesis of 5,7-diarylpyrazolo[1,5-a]pyrimidines.
Scheme 45: Synthesis of 6,7-dihydropyrazolo[1,5-a]pyrimidines in PEG-400.
Scheme 46: Synthesis of 7-heteroarylpyrazolo[1,5-a]pyrimidine-3-carboxamides.
Scheme 47: Synthesis of 7-heteroarylpyrazolo[1,5-a]pyrimidine derivatives under conventional heating and micro...
Scheme 48: Synthesis of N-aroylpyrazolo[1,5-a]pyrimidine-5-amines.
Scheme 49: Regioselective synthesis of ethyl pyrazolo[1,5-a]pyrimidine-7-carboxylate.
Scheme 50: Sodium methoxide-catalyzed synthesis of 3-cyano-6,7-diarylpyrazolo[1,5-a]pyrimidines.
Scheme 51: Synthesis of various pyrazolo[3,4-d]pyrimidine derivatives.
Scheme 52: Synthesis of hydrazinopyrazolo[3,4-d]pyrimidine derivatives.
Scheme 53: Synthesis of N-arylidinepyrazolo[3,4-d]pyrimidin-5-amines.
Scheme 54: Synthesis of pyrazolo[3,4-d]pyrimidinyl-4-amines.
Scheme 55: Iodine-catalyzed synthesis of pyrazolo[3,4-d]pyrimidinones.
Scheme 56: Synthesis of ethyl 6-amino-2H-pyrazolo[3,4-d]pyrimidine-4-carboxylate.
Scheme 57: Synthesis of 4-substituted-(3,6-dihydropyran-4-yl)-1H-pyrazolo[3,4-d]pyrimidines.
Scheme 58: Synthesis of 1-(2,4-dichlorophenyl)pyrazolo[3,4-d]pyrimidin-4-yl carboxamides.
Scheme 59: Synthesis of 5-(1,3,4-thidiazol-2-yl)pyrazolo[3,4-d]pyrimidine.
Scheme 60: One pot POCl3-catalyzed synthesis of 1-arylpyrazolo[3,4-d]pyrimidin-4-ones.
Scheme 61: Synthesis of 4-amino-N1,C3-dialkylpyrazolo[3,4-d]pyrimidines under Suzuki conditions.
Scheme 62: Microwave-assisted synthesis of pyrazolo[3,4-b]pyrazines.
Scheme 63: Synthesis and derivatization of pyrazolo[3,4-b]pyrazine-5-carbonitriles.
Scheme 64: Synthesis of 2-thioxo-pyrazolo[1,5-a][1,3,5]triazin-4-ones.
Scheme 65: Synthesis of 2,3-dihydropyrazolo[1,5-a][1,3,5]triazin-4(1H)-one.
Scheme 66: Synthesis of pyrazolo[1,5-a][1,3,5]triazine-8-carboxylic acid ethyl ester.
Scheme 67: Microwave-assisted synthesis of 4,7-dihetarylpyrazolo[1,5-a][1,3,5]triazines.
Scheme 68: Alternative synthetic route to 4,7-diheteroarylpyrazolo[1,5-a][1,3,5]triazines.
Scheme 69: Synthesis of 4-aryl-2-ethylthio-7-methylpyrazolo[1,5-a][1,3,5]triazines.
Scheme 70: Microwave-assisted synthesis of 4-aminopyrazolo[1,5-a][1,3,5]triazine.
Scheme 71: Synthesis of pyrazolo[3,4-d][1,2,3]triazines from pyrazol-5-yl diazonium salts.
Scheme 72: Synthesis of 2,5-dihydropyrazolo[3,4-e][1,2,4]triazines.
Scheme 73: Synthesis of pyrazolo[5,1-c][1,2,4]triazines via diazopyrazolylenaminones.
Scheme 74: Synthesis of pyrazolo[5,1-c][1,2,4]triazines in presence of sodium acetate.
Scheme 75: Synthesis of various 7-diazopyrazolo[5,1-c][1,2,4]triazine derivatives.
Scheme 76: One pot synthesis of pyrazolo[5,1-c][1,2,4]triazines.
Scheme 77: Synthesis of 4-amino-3,7,8-trinitropyrazolo-[5,1-c][1,2,4]triazines.
Scheme 78: Synthesis of tricyclic pyrazolo[5,1-c][1,2,4]triazines by azocoupling reaction.
Nucleophilic dearomatization of 4-aza-6-nitrobenzofuroxan by CH acids in the synthesis of pharmacology-oriented compounds
- Alexey M. Starosotnikov,
- Dmitry V. Shkaev,
- Maxim A. Bastrakov,
- Ivan V. Fedyanin,
- Svyatoslav A. Shevelev and
- Igor L. Dalinger
Beilstein J. Org. Chem. 2017, 13, 2854–2861, doi:10.3762/bjoc.13.277
- hypertension. Dihydropyridine derivatives are relatively vascular selective in their mechanism of action in lowering blood pressure [31][32]. Dimeric dihydropyridines are used as the precursors for HIV-1 protease inhibitors [33][34]. The furoxan system is used in the design of new NO donors [35][36][37][38][39
Graphical Abstract
Scheme 1: Beirut reaction.
Scheme 2: Reactivity of 4,6-dinitrobenzofuroxan.
Scheme 3: Reactivity of ANBF (1).
Scheme 4: Synthesis of ANBF.
Scheme 5: Reactions of ANBF with β-dicarbonyl compounds.
Figure 1: General view of molecule 12 in crystal. Anisotropic displacement parameters for non-hydrogen atoms ...
Scheme 6: Reaction of ANBF with 2,4,6-trinitrotoluene.
Figure 2: Partial 1H NMR spectrum of compound 15 in DMSO-d6.
Figure 3: General view of molecule 15 in crystal. Anisotropic displacement parameters for non-hydrogen atoms ...
Scheme 7: Plausible mechanism of adducts formation.
Recent progress in the racemic and enantioselective synthesis of monofluoroalkene-based dipeptide isosteres
- Myriam Drouin and
- Jean-François Paquin
Beilstein J. Org. Chem. 2017, 13, 2637–2658, doi:10.3762/bjoc.13.262
- isomerization or epimerization, cyclic pseudopeptides using Fmoc SPPS [48][50]. Biological studies were conducted on monofluoroalkene-containing analogues of FC131, which is a known antagonist of the chemokine receptor CXCR4. The latter has implications in cancer metastasis and HIV 1 infection. Anti-HIV 1
- dipeptide isostere Lys-ψ[(Z)-CF=CH]-Lys into a fusion inhibitory peptide active against HIV 1, SC29EK, was investigated [49]. Weak to moderate anti-HIV activity was observed for the fluorinated analogues, but the potency was always lower than for SC29EK. This suggested than the H-bonding behaviour was
Graphical Abstract
Figure 1: Selected amide bond isosteres.
Figure 2: Monofluoroalkene as an amide bond isostere.
Scheme 1: Synthesis of Cbz-Gly-ψ[(Z)-CF=CH]-Gly using a HWE olefination by Sano and co-workers.
Scheme 2: Synthesis of Phth-Gly-ψ[CF=CH]-Gly using the Julia–Kocienski olefination by Lequeux and co-workers.
Scheme 3: Synthesis of Boc-Nva-ψ[(Z)-CF=CH]-Gly by Taguchi and co-workers.
Figure 3: Mutant tripeptide containing two different peptide bond isosteres.
Scheme 4: Chromium-mediated synthesis of Boc-Ser(PMB)-ψ[(Z)-CF=CH]-Gly-OMe by Konno and co-workers.
Scheme 5: Synthesis of Cbz-Gly-ψ[(E)-CF=C]-Pro by Sano and co-workers.
Scheme 6: Synthesis of Cbz-Gly-ψ[(Z)-CF=C]-Pro by Sano and co-workers.
Scheme 7: Stereoselective synthesis of Fmoc-Gly-ψ[(Z)-CF=CH]-Phe by Pannecoucke and co-workers.
Scheme 8: Ring-closure metathesis to prepare Gly-ψ[(E)-CF=CH]-Phg by Couve-Bonnaire and co-workers.
Scheme 9: Stereoselective synthesis of Fmoc-Gly-ψ[(Z)-CF=CH]-Phe by Dory and co-workers.
Scheme 10: Diastereoselective addition of Grignard reagents to sulfinylamines derived from α-fluoroenals by Pa...
Scheme 11: NHC-mediated synthesis of monofluoroalkenes by Otaka and co-workers.
Scheme 12: Stereoselective synthesis of Boc-Tyr-ψ[(Z)-CF=CH]-Gly by Altman and co-workers.
Scheme 13: Synthesis of the tripeptide Boc-Asp(OBn)-Pro-ψ[(Z)-CF=CH)-Val-CH2OH by Miller and co-workers.
Scheme 14: Copper-catalyzed synthesis of monofluoralkenes by Taguchi and co-workers.
Scheme 15: One-pot intramolecular redox reaction to access amide-type isosteres by Otaka and co-workers.
Scheme 16: Copper-mediated reduction, transmetalation and asymmetric alkylation by Fujii and co-workers.
Scheme 17: Synthesis of (E)-monofluoroalkene-based dipeptide isostere by Fujii and co-workers.
Scheme 18: Diastereoselective synthesis of MeOCO-Val-ψ[(Z)-CF=C]-Pro isostere by Chang and co-workers.
Scheme 19: Asymmetric synthesis of Fmoc-Ala-ψ[(Z)-CF=C]-Pro by Pannecoucke and co-workers.
Scheme 20: Synthesis of Fmoc-Val-ψ[(E)-CF=C]-Pro by Pannecoucke and co-workers.
Figure 4: BMS-790052 and its fluorinated analogue.
Figure 5: Bioactivities of pentapeptide analogues based on the relative maximum agonistic activity at 10 nM o...
Figure 6: Structures and affinities of the Leu-enkephalin and its fluorinated analogue. The affinity towards ...
Figure 7: Activation of the opioid receptor DOPr by Leu-enkephaline and a fluorinated analogue.
What contributes to an effective mannose recognition domain?
- Christoph P. Sager,
- Deniz Eriş,
- Martin Smieško,
- Rachel Hevey and
- Beat Ernst
Beilstein J. Org. Chem. 2017, 13, 2584–2595, doi:10.3762/bjoc.13.255
- Brewer reviewed the role of density and number of glycan epitopes involved in multivalent carbohydrate interactions for legume lectins as well as for lectins of the innate immune system [74]. As an example, HIV-1 establishes multivalent contacts to DC-SIGN (E)-decorated dendritic cells in order to bypass
- host immune attack. Thus, DC-SIGN plays a key role in the dissemination of HIV-1 by capturing of HIV-1 at entry sites of infection and subsequent transport of the virus to CD4+ T cells in lymphoid tissues. The weak monovalent binding affinity of DC-SIGN (E) is compensated for by a multivalent display
- of oligomannosides on viral envelop glycoprotein gp120, facilitating stronger adhesion between dendritic cells and HIV-1 [43][75][76]. This multivalent binding interaction results in an enhancement in binding by several orders of magnitude, from a KD of 26 μM for monovalent Man9GlcNAc2, as compared
Graphical Abstract
Figure 1: CRDs of the analyzed crystal structures, with mannose pyranosyl units similarly aligned in each str...
Figure 2: A) The solvent exposed binding site of E-selectin interacting with sLex (PDB: 1G1T) [53]. B) The buried...
Figure 3: Dynamic mannose–receptor interactions (20 ns MD simulations), grouped according to the nature of th...
Figure 4: Desolvation of hydroxy groups. A) The desolvation cost of a single hydroxy group associated with th...
Figure 5: Model view of the binding site interactions of DC-SIGN (E) and BC2L-A (H) with water. A) The solven...
Figure 6: Thermodynamic fingerprints of sLex bound to E-selectin and n-heptyl α-D-mannoside bound to FimHLD (I...
Figure 7: Schematic overview of the conformational changes of FimH (I). FimH crystal structures, which corres...
Figure 8: Comparison of the holo (white) and apo (green, magenta) binding sites of LecB (G) and BDCA-2 (A), r...
A novel synthetic approach to hydroimidazo[1,5-b]pyridazines by the recyclization of itaconimides and HPLC–HRMS monitoring of the reaction pathway
- Dmitry Yu. Vandyshev,
- Khidmet S. Shikhaliev,
- Andrey Yu. Potapov,
- Michael Yu. Krysin,
- Fedor I. Zubkov and
- Lyudmila V. Sapronova
Beilstein J. Org. Chem. 2017, 13, 2561–2568, doi:10.3762/bjoc.13.252
- through the N1–C5 bond of the latter, have been studied to a lesser extent. So, for imidazo[1,5-b]pyridazines, inhibitory activity was found against the viruses of human immunodeficiency HIV-1 [12], influenza [13], and hepatitis C [14]. They also act as stimulators of guanylate cyclase [10], inhibitors of
Graphical Abstract
Scheme 1: Intramolecular cyclization of 3-(aminomethyl)pyridazines and related compounds (route A). Condition...
Scheme 2: Heterocyclization of 1-aminoimidazoles with 1,3-dicarbonyl or α,β-unsaturated carbonyl compounds (r...
Scheme 3: Heterocyclization of 1-aminoimidazoles with structural transformation of dielectrophilic reagents (...
Scheme 4: Recyclization of N-arylitaconimides 1 with 1,2-diaminobenzimidazole (2).
Scheme 5: Possible synthetic routes of the interaction of itaconimides 1 with diaminoimidazole 4.
Scheme 6: 1H,13C-HMBC correlations: the most significant correlations for imidazopyridazine 9d and possible f...
Phosphonic acid: preparation and applications
- Charlotte M. Sevrain,
- Mathieu Berchel,
- Hélène Couthon and
- Paul-Alain Jaffrès
Beilstein J. Org. Chem. 2017, 13, 2186–2213, doi:10.3762/bjoc.13.219
- addition of POCl3 or PCl3 [222] is a method that produces in one step the aminomethylene bis-phosphonic acid [228] (Figure 33A). This methodology was applied to prepare the compound 119 [229] that was assessed as HIV-1 integrase inhibitor. Compound 120 [230] was prepared simply by the refluxing
Graphical Abstract
Figure 1: Summary of the synthetic routes to prepare phosphonic acids detailed in this review. The numbers in...
Figure 2: Chemical structure of dialkyl phosphonate, phosphonic acid and illustration of the simplest phospho...
Figure 3: Illustration of some phosphonic acid exhibiting bioactive properties. A) Phosphonic acids for biome...
Figure 4: Illustration of the use of phosphonic acids for their coordination properties and their ability to ...
Figure 5: Hydrolysis of dialkyl phosphonate to phosphonic acid under acidic conditions.
Figure 6: Examples of phosphonic acids prepared by hydrolysis of dialkylphosphonate with HCl 35% at reflux (16...
Figure 7: A) and B) Observation of P–C bond breaking during the hydrolysis of phosphonate with concentrated H...
Figure 8: Mechanism of the hydrolysis of dialkyl phosphonate with HCl in water.
Figure 9: Hydrolysis of bis-tert-butyl phosphonate 28 into phosphonic acid 29 [137].
Figure 10: A) Hydrolysis of diphenyl phosphonate into phosphonic acid in acidic media. B) Examples of phosphon...
Figure 11: Suggested mechanism occurring for the first step of the hydrolysis of diphenyl phosphonate into pho...
Figure 12: A) Hydrogenolysis of dibenzyl phosphonate to phosphonic acid. B) Compounds 33, 34 and 35 were prepa...
Figure 13: A) Preparation of phosphonic acid from diphenyl phosphonate with the Adam’s catalyst. B) Compounds ...
Figure 14: Suggested mechanism for the preparation of phosphonic acid from dialkyl phosphonate using bromotrim...
Figure 15: A) Reaction of the phosphonate-thiophosphonate 37 with iodotrimethylsilane followed by methanolysis...
Figure 16: Synthesis of hydroxymethylenebisphosphonic acid by reaction of tris(trimethylsilyl) phosphite with ...
Figure 17: Synthesis of the phosphonic acid disodium salt 48 by reaction of mono-hydrolysed phosphonate 47 wit...
Figure 18: Phosphonic acid synthesized by the sequence 1) bromotrimethylsilane 2) methanolysis or hydrolysis. ...
Figure 19: Polyphosphonic acids and macromolecular compounds prepared by the hydrolysis of dialkyl phosphonate...
Figure 20: Examples of organometallic complexes functionalized with phosphonic acids that were prepared by the...
Figure 21: Side reaction observed during the hydrolysis of methacrylate monomer functionalized with phosphonic...
Figure 22: Influence of the reaction time during the hydrolysis of compound 76.
Figure 23: Dealkylation of dialkyl phosphonates with boron tribromide.
Figure 24: Dealkylation of diethylphosphonate 81 with TMS-OTf.
Figure 25: Synthesis of substituted phenylphosphonic acid 85 from the phenyldichlorophosphine 83.
Figure 26: Hydrolysis of substituted phenyldichlorophosphine oxide 86 under basic conditions.
Figure 27: A) Illustration of the synthesis of chiral phosphonic acids from phosphonodiamides. B) Examples of ...
Figure 28: A) Illustration of the synthesis of the phosphonic acid 98 from phosphonodiamide 97. B) Use of cycl...
Figure 29: Synthesis of tris(phosphonophenyl)phosphine 109.
Figure 30: Moedritzer–Irani reaction starting from A) primary amine or B) secondary amine. C) Examples of phos...
Figure 31: Phosphonic acid-functionalized polymers prepared by Moedritzer–Irani reaction.
Figure 32: Reaction of phosphorous acid with imine in the absence of solvent.
Figure 33: A) Reaction of phosphorous acid with nitrile and examples of aminomethylene bis-phosphonic acids. B...
Figure 34: Reaction of carboxylic acid with phosphorous acid and examples of compounds prepared by this way.
Figure 35: Synthesis of phosphonic acid by oxidation of phosphinic acid (also identified as phosphonous acid).
Figure 36: Selection of reaction conditions to prepare phosphonic acids from phosphinic acids.
Figure 37: Synthesis of phosphonic acid from carboxylic acid and white phosphorus.
Figure 38: Synthesis of benzylphosphonic acid 136 from benzaldehyde and red phosphorus.
Figure 39: Synthesis of graphene phosphonic acid 137 from graphite and red phosphorus.
High-speed vibration-milling-promoted synthesis of symmetrical frameworks containing two or three pyrrole units
- Marco Leonardi,
- Mercedes Villacampa and
- J. Carlos Menéndez
Beilstein J. Org. Chem. 2017, 13, 1957–1962, doi:10.3762/bjoc.13.190
- proved to be useful include the protease of the human immunodeficiency virus HIV [1], cellular prion protein, PrPc [2], and the transient receptor potential melastatin 8 (TRPM8) channel receptor [3]. The synthesis of these symmetrical molecules normally relies on multistep sequences. Due to the special
Graphical Abstract
Scheme 1: Our synthetic planning and structural diversity of starting materials employed in our work.
Scheme 2: Pseudo five-component reactions affording symmetrical bispyrrole derivatives joined by a spacer.
Figure 1: Scope of the synthesis of symmetrical bispyrrole derivatives.
Scheme 3: A pseudo-seven-component reaction that affords a terpyrrole derivative with a functionalized spacer....
Scheme 4: Homodimerization of 2-allyl- and 2-homoallylpyrroles via cross-metathesis reactions.
Glyco-gold nanoparticles: synthesis and applications
- Federica Compostella,
- Olimpia Pitirollo,
- Alessandro Silvestri and
- Laura Polito
Beilstein J. Org. Chem. 2017, 13, 1008–1021, doi:10.3762/bjoc.13.100
- -based approach, which aim to trigger the production of specific and functional antibodies that prevent initial infection limiting pathogen/viral dissemination. Recent publications suggest that many different aspects are becoming clear and have to be underlined. The design of anti HIV-1 vaccines depends
- on the identification of sugar epitopes of the surface envelope glycoprotein of HIV-1, capable of eliciting a protective response. GAuNPs coated with high-mannose type oligosaccharide of HIV-1 gp120, were prepared as glycoconjugate systems able to mimic the natural presentation of gp-120 high-mannose
- glycans. It was demonstrated that they were able to inhibit DC-SIGN-mediated HIV-1 infections and to interfere with the antibody/gp120 binding process. Most of these systems proved able to elicit the production of carbohydrate-specific antibodies in animals, though the generated IgGs turned out to be
Graphical Abstract
Figure 1: Schematic overview on the glyco-gold nanoparticles synthetic approaches.
Figure 2: Glyco-gold nanoparticles: metallic core and glyco-coating contribute to the production of the versa...
Figure 3: The protein–carbohydrate interactions analyzed by conventional dark field microscopy. The interacti...
Figure 4: Copper-free cycloaddition (SPAAC) of azido galactoside on cyclooctyne and schematic depiction of Au...
Figure 5: A photoaffinity labeling (PAL) approach based on glyco-gold nanoparticles is able to recognize and ...
Figure 6: Design of the fiber-type “Sugar Chips”. AuNPs are firstly immobilized on an optical fiber functiona...
Figure 7: Design of GAuNPs, displaying both sugar residues and the anticancer Au(I)PPh3. Reprinted with permi...
Revaluation of biomass-derived furfuryl alcohol derivatives for the synthesis of carbocyclic nucleoside phosphonate analogues
- Bemba Sidi Mohamed,
- Christian Périgaud and
- Christophe Mathé
Beilstein J. Org. Chem. 2017, 13, 251–256, doi:10.3762/bjoc.13.28
- transposition giving rise to carbocyclic nucleoside phosphonates having structural similarity with carbonucleosides belonging to the neplanocin family. All the newly synthesized compounds were evaluated for their antiviral properties against HIV-1, Zika virus, Dengue-2 virus, HSV-1, HSV-2 and Chikungunya virus
Graphical Abstract
Figure 1: Retrosynthetic pathway for the synthesis of the target carbocyclic nucleoside methylphosphonates.
Scheme 1: Reagents and conditions: (a) (CH3O)2P(O)CH3, n-BuLi, THF, −78 °C/rt, 2 h, 63%; (b) H2, Pd/C, MeOH, ...
Scheme 2: Reagents and conditions: (a) N6-bis-Boc-adenine or 2-amino-6-chloropurine, PPh3, DIAD, THF, 0 °C to...
Scheme 3: Reagents and conditions: (a) N6-bis-Boc-adenine, PPh3, DIAD, THF, rt, 56%; (b) TFA, Cl(CH2)2Cl, rt,...
Figure 2: Numbering for 14 and 16.
Figure 3: Selected NOESY correlations for compound (+/−)-16.
Scheme 4: Reagents and conditions: (a) i) Boc2O, DMAP, THF, rt; ii) K2CO3, MeOH, 75%; (b) PPh3, DIAD, THF, rt...
Scheme 5: Reagents and conditions: (a) N6-Bz-adenine or 2-amino-6-chloropurine, PPh3, DIAD, THF, 0 °C to rt, ...
Computational methods in drug discovery
- Sumudu P. Leelananda and
- Steffen Lindert
Beilstein J. Org. Chem. 2016, 12, 2694–2718, doi:10.3762/bjoc.12.267
- membrane proteins where membrane permeability is considered to be important for drugs to be useful [10][11]. Successes have been reported for SBDD and it has contributed to many compounds reaching clinical trials and get FDA approvals to go into the market [12]. HIV-1 (Human Immunodeficiency Virus I
- longer than they could have without the treatment [13][14]. Saquinavir is one of the first HIV-1 protease targeted drugs to reach the market (Figure 2a and 2c) [15]. Amprenavir is another drug that was developed to target HIV-1 protease that was also developed influenced by SBDD (Figure 2b and 2d) [16
- phosphate probe which are used to identify the binding sites for drug-like molecules and phosphorylated ligands (such as ATP) respectively [92]. The best ligand binding site identified in HIV-1 protease by SiteHound is shown in Figure 4. This ligand binding site is the known inhibitor binding site in HIV-1
Graphical Abstract
Figure 1: Schematic representation of a computer-aided drug discovery (CADD) pipeline. CADD methods are broad...
Figure 2: FDA approved drugs Saquinavir and Amprenavir for the treatment of HIV infections. (a) The structure...
Figure 3: (a) The crystal structure showing the binding of Dorzolamide (orange) to carbonic anhydrase II (pur...
Figure 4: The best ligand binding site identified by SiteHound in HIV-1 protease. The ligand binding pocket i...
Figure 5: Binding mode prediction. The known inhibitor Dorzolamide is docked into Carbonic anhydrase II cryst...
Figure 6: The molecular structure of Raltegravir. Raltegravir is an FDA approved drug used in the treatment o...
Figure 7: An example alchemical thermodynamic cycle for a protein–ligand binding free energy calculation. The...
Figure 8: Schematic diagram showing the steps involved in QSAR. Known drug molecule activity and descriptor d...
Figure 9: A few drugs discovered with the help of ligand-based drug discovery tools. (a) Zolmitriptan: used a...
Interactions between cyclodextrins and cellular components: Towards greener medical applications?
- Loïc Leclercq
Beilstein J. Org. Chem. 2016, 12, 2644–2662, doi:10.3762/bjoc.12.261
Graphical Abstract
Scheme 1: Structure and conventional representation of native CDs.
Scheme 2: Proposed mechanism for morphological changes in erythrocytes induced by methylated CDs.
Scheme 3: Proposed mechanism for the conformational change of egg white lysozyme with temperature elevating i...
Scheme 4: Sugar hydrophobicity scale according to Janado and Yano and correlation with the binding constant v...
Scheme 5: Principle of chemically switched DNA intercalators based on anthryl(alkylamino)-β-CD/1-adamantanol ...
Scheme 6: Normal (left) and diseased artery (right).
Scheme 7: Kinetics of [DiC10] insertion into the viral envelope without (left) or with γ-CD (right). Note tha...
Application of Cu(I)-catalyzed azide–alkyne cycloaddition for the design and synthesis of sequence specific probes targeting double-stranded DNA
- Svetlana V. Vasilyeva,
- Vyacheslav V. Filichev and
- Alexandre S. Boutorine
Beilstein J. Org. Chem. 2016, 12, 1348–1360, doi:10.3762/bjoc.12.128
- atom in the chain, and 10 possessing several ethylene glycol moieties were used to increase the solubility of modified polyamides in water. Selection of the target DNA and design of TFOs and MGBs The polypurine tract of the HIV-1 provirus is a valuable target for MGB-TFO conjugates [35]. It has a 16-bp
Graphical Abstract
Figure 1: A) Formation of nucleotide triplets in parallel and antiparallel (relatively to polypurine strand) ...
Figure 2: Synthesis of MGB-fluorophore (A) and MGB-TFO (B) conjugates using CuACC. Linker length and composit...
Figure 3: Bifunctional linkers for conjugation of oligonucleotides and polyamides using CuACC.
Figure 4: The target duplex contains a 29 base pair fragment from HIV proviral DNA [35] and a T4 hairpin is conne...
Figure 5: A) Sequence derived from the murine pericentromere repeat fragment with only one target site for th...
Figure 6: Synthesis of azide- and alkyne-modified MGBs.
Figure 7: Structures of fluorescent probes synthesized by "click chemistry".
Figure 8: Titration of the probes F1-NH2-MM14 (12 µM, A, C) and F1-NH2-TO (10 µM, B, D) by the target DNA dup...
Figure 9: Synthesis of modified oligonucleotides containing an alkyne group.
Figure 10: Gel electrophoresis of oligonucleotides modified by alkyne linkers: A – oligonucleotide HIVP (detec...
Figure 11: TINA-TFOs bearing a 3'-alkyne group for antiparallel triplex formation with the target HIV proviral...
Figure 12: Structures of polyamide-TFO conjugates.
Figure 13: Electrophoresis analysis of samples from reaction mixtures after click reactions between alkyne-TFO...
Figure 14: Electrophoresis analysis of reaction mixtures in 20% denaturing polyacrylamide gel after TINA-TFO-M...
Figure 15: Electrophoretic analysis of reaction mixtures in standard 20% denaturing PAGE after DNA-templated s...
Figure 16: Non-denaturing gel electrophoresis analysis of conjugate 28 with fluorescein-labeled target HIV dup...
Cyclisation mechanisms in the biosynthesis of ribosomally synthesised and post-translationally modified peptides
- Andrew W. Truman
Beilstein J. Org. Chem. 2016, 12, 1250–1268, doi:10.3762/bjoc.12.120
- formed by the head-to-tail cyclisation of two nonapeptides that are themselves derived from the C-terminal region of precursor peptides, and both heterodimers or homodimers can be formed in this process [84][144]. Along with their antimicrobial activity, these peptides can inhibit fusion of HIV-1 to host
Graphical Abstract
Figure 1: Schematic of RiPP biosynthesis. Thiazole/oxazole formation is represented by the blue heterocycle (...
Figure 2: Examples of heterocycles in RiPPs alongside the precursor peptides that these molecules derive from...
Figure 3: Formation of thiazoles and oxazoles in RiPPs. A) Biosynthesis of microcin B17. B) Mechanistic model...
Figure 4: Lanthionine bond formation. A) Nisin and its precursor peptide. B) Mechanism of lanthionine bond fo...
Figure 5: S-[(Z)-2-Aminovinyl]-D-cysteine (AviCys) formation in the epidermin pathway. A) Mechanisms for deca...
Figure 6: Cyclisation in the biosynthesis of thiopeptides. A) Mechanism of TclM-catalysed heterocyclisation i...
Figure 7: ATP-dependent macrocyclisation. A) General mechanism for ATP-dependent macrolactonisation or macrol...
Figure 8: Peptidase-like macrolactam formation. A) General mechanism. B) Examples of RiPPs cyclised by serine...
Figure 9: Structure of autoinducing peptide AIP-I from Staphylococcus aureus and the sequence of the correspo...
Figure 10: Radical cyclisation in RiPP biosynthesis. A) AlbA-catalysed formation of thioethers in the biosynth...
Figure 11: RiPPs with uncharacterised mechanisms of cyclisation. Unusual heterocycles in ComX and methanobacti...
Catalytic asymmetric synthesis of biologically important 3-hydroxyoxindoles: an update
- Bin Yu,
- Hui Xing,
- De-Quan Yu and
- Hong-Min Liu
Beilstein J. Org. Chem. 2016, 12, 1000–1039, doi:10.3762/bjoc.12.98
- applied to the synthesis of a drug candidate, which had been proved to possess better inhibitory activity than efavirenz against HIV-1 reverse transcriptase [19]. Besides, the reactions may provide an efficient route to the optically pure propargylic alcohols. Ir-catalyzed synthesis of 3-hydroxyoxindoles
Graphical Abstract
Figure 1: 3-Hydroxyoxindole-containing natural products and biologically active molecules.
Scheme 1: Chiral CNN pincer Pd(II) complex 1 catalyzed asymmetric allylation of isatins.
Scheme 2: Asymmetric allylation of ketimine catalyzed by the chiral CNN pincer Pd(II) complex 2.
Scheme 3: Pd/L1 complex-catalyzed asymmetric allylation of 3-O-Boc-oxindoles.
Scheme 4: Cu(OTf)2-catalyzed asymmetric direct addition of acetonitrile to isatins.
Scheme 5: Chiral tridentate Schiff base/Cu complex catalyzed asymmetric Friedel–Crafts alkylation of isatins ...
Scheme 6: Guanidine/CuI-catalyzed asymmetric alkynylation of isatins with terminal alkynes.
Scheme 7: Asymmetric intramolecular direct hydroarylation of α-ketoamides.
Scheme 8: Plausible catalytic cycle for the direct hydroarylation of α-ketoamides.
Scheme 9: Ir-catalyzed asymmetric arylation of isatins with arylboronic acids.
Scheme 10: Enantioselective decarboxylative addition of β-ketoacids to isatins.
Scheme 11: Ruthenium-catalyzed hydrohydroxyalkylation of olefins and 3-hydroxy-2-oxindoles.
Scheme 12: Proposed catalytic mechanism and stereochemical model.
Scheme 13: In-catalyzed allylation of isatins with stannylated reagents.
Scheme 14: Modified protocol for the synthesis of allylated 3-hydroxyoxindoles.
Scheme 15: Hg-catalyzed asymmetric allylation of isatins with allyltrimethylsilanes.
Scheme 16: Enantioselective additions of organoborons to isatins.
Scheme 17: Asymmetric aldol reaction of isatins with cyclohexanone.
Scheme 18: Enantioselective aldol reactions of aliphatic aldehydes with isatin derivatives and the plausible t...
Scheme 19: Enantioselective aldol reaction of isatins and 2,2-dimethyl-1,3-dioxan-5-one.
Scheme 20: Asymmetric aldol reactions between ketones and isatins.
Scheme 21: Phenylalanine lithium salt-catalyzed asymmetric synthesis of 3-alkyl-3-hydroxyoxindoles.
Scheme 22: Aldolization between isatins and dihydroxyacetone derivatives.
Scheme 23: One-pot asymmetric synthesis of convolutamydine A.
Scheme 24: Asymmetric aldol reactions of cyclohexanone and acetone with isatins.
Scheme 25: Aldol reactions of acetone with isatins.
Scheme 26: Aldol reactions of ketones with isatins.
Scheme 27: Enantioselective allylation of isatins.
Scheme 28: Asymmetric aldol reaction of trifluoromethyl α-fluorinated β-keto gem-diols with isatins.
Scheme 29: Plausible mechanism proposed for the asymmetric aldol reaction.
Scheme 30: Asymmetric aldol reaction of 1,1-dimethoxyacetone with isatins.
Scheme 31: Enantioselective Friedel-Crafts reaction of phenols with isatins.
Scheme 32: Enantioselective addition of 1-naphthols with isatins.
Scheme 33: Enantioselective aldol reaction between 3-acetyl-2H-chromen-2-ones and isatins.
Scheme 34: Stereoselective Mukaiyama–aldol reaction of fluorinated silyl enol ethers with isatins.
Scheme 35: Asymmetric vinylogous Mukaiyama–aldol reaction between 2-(trimethylsilyloxy)furan and isatins.
Scheme 36: β-ICD-catalyzed MBH reactions of isatins with maleimides.
Scheme 37: β-ICD-catalyzed MBH reactions of 7-azaisatins with maleimides and activated alkenes.
Scheme 38: Enantioselective aldol reaction of isatins with ketones.
Scheme 39: Direct asymmetric vinylogous aldol reactions of allyl ketones with isatins.
Scheme 40: Enantioselective aldol reactions of ketones with isatins.
Scheme 41: The MBH reaction of isatins with α,β-unsaturated γ-butyrolactam.
Scheme 42: Reactions of tert-butyl hydrazones with isatins followed by oxidation.
Scheme 43: Aldol reactions of isatin derivatives with ketones.
Scheme 44: Enantioselective decarboxylative cyanomethylation of isatins.
Scheme 45: Catalytic kinetic resolution of 3-hydroxy-3-substituted oxindoles.
Scheme 46: Lewis acid catalyzed Friedel–Crafts alkylation of 3-hydroxy-2-oxindoles with electron-rich phenols.
Scheme 47: Lewis acid catalyzed arylation of 3-hydroxyoxindoles with aromatics.
Scheme 48: Synthetic application of 3-arylated disubstituted oxindoles in the construction of core structures ...
Scheme 49: CPA-catalyzed dearomatization and arylation of 3-indolyl-3-hydroxyoxindoles with tryptamines and 3-...
Scheme 50: CPA-catalyzed enantioselective decarboxylative alkylation of β-keto acids with 3-hydroxy-3-indolylo...
Scheme 51: BINOL-derived imidodiphosphoric acid-catalyzed enantioselective Friedel–Crafts reactions of indoles...
Scheme 52: CPA-catalyzed enantioselective allylation of 3-indolylmethanols.
Scheme 53: 3-Indolylmethanol-based substitution and cycloaddition reactions.
Scheme 54: CPA-catalyzed asymmetric [3 + 3] cycloaddtion reactions of 3-indolylmethanols with azomethine ylide...
Scheme 55: CPA-catalyzed three-component cascade Michael/Pictet–Spengler reactions of 3-indolylmethanols and a...
Scheme 56: Acid-promoted chemodivergent and stereoselective synthesis of diverse indole derivatives.
Scheme 57: CPA-catalyzed asymmetric formal [3 + 2] cycloadditions.
Scheme 58: CPA-catalyzed enantioselective cascade reactions for the synthesis of C7-functionlized indoles.
Scheme 59: Lewis acid-promoted Prins cyclization of 3-allyl-3-hydroxyoxindoles with aldehydes.
Scheme 60: Ga(OTf)3-catalyzed reactions of allenols and phenols.
Scheme 61: I2-catalyzed construction of pyrrolo[2.3.4-kl]acridines from enaminones and 3-indolyl-3-hydroxyoxin...
Scheme 62: CPA-catalyzed asymmetric aza-ene reaction of 3-indolylmethanols with cyclic enaminones.
Scheme 63: Asymmetric α-alkylation of aldehydes with 3-indolyl-3-hydroxyoxindoles.
Scheme 64: Organocatalytic asymmetric α-alkylation of enolizable aldehydes with 3-indolyl-3-hydroxyoxindoles a...
A journey in bioinspired supramolecular chemistry: from molecular tweezers to small molecules that target myotonic dystrophy
- Steven C. Zimmerman
Beilstein J. Org. Chem. 2016, 12, 125–138, doi:10.3762/bjoc.12.14
- ligand, bound in the groove of the HIV-1 frameshift site (FS), and (3) the (CUG)6 X-ray and HIV-1 FS NMR structures were both A-form and similar suggesting replacement of the ammonium ions in DB213 with triaminotriazine units. Ligand 30 was studied in collaboration with both Anne Baranger and Paul
Graphical Abstract
Figure 1: Photographs of Howard E. Zimmerman (July 5, 1926–February 12, 2012) (left) and Jane Zimmerman (née ...
Figure 2: (a) Schematic double helix fully saturated with intercalator (in purple) according to the neighbor ...
Figure 3: Bismethidium molecular tweezer 3 proposed as a graduate student at Columbia University, which was q...
Figure 4: Adenine 8 recognition by carboxylic acid containing tweezer 9 and a component analysis showing “com...
Figure 5: The first determination of the cost of freezing single bond rotations in a host–guest complex.
Figure 6: Glycouril-based molecular clip 16 and 17 developed by Nolte, an example of Harmata’s chiral Kagan-e...
Figure 7: Macrocyclic diacridines and dinaphthalene and the intercalation complexes they may form with one ch...
Figure 8: (a) Hairpin structure of CUGexp seen in (CUG)12. (b) U–U or T–T mismatches with no inter-strand hyd...
Figure 9: (a) CTG trinucleotide repeat expansion in DMPK gene produces expanded transcripts, one which CUGexp...
Structure and conformational analysis of spiroketals from 6-O-methyl-9(E)-hydroxyiminoerythronolide A
- Ana Čikoš,
- Irena Ćaleta,
- Dinko Žiher,
- Mark B. Vine,
- Ivaylo J. Elenkov,
- Marko Dukši,
- Dubravka Gembarovski,
- Marina Ilijaš,
- Snježana Dragojević,
- Ivica Malnar and
- Sulejman Alihodžić
Beilstein J. Org. Chem. 2015, 11, 1447–1457, doi:10.3762/bjoc.11.157
- sponges, which display extraordinary antitumor activity [29]. At the same time, the spiroketal-containing integramycin acts as an HIV-1 protease inhibitor [27]. The studies of Hayashi et al. have shown that the integrity of the spiroketal subunit is essential for the inhibition of telomerase by
Graphical Abstract
Scheme 1: Synthetic route to spiroketals 2–4. Reaction conditions: a) Na2S2O5/HCOOH/EtOH/water/70 °C, b) DCl/...
Figure 1: Modelling-derived structure of 2 showing key nOe interactions (calculated distances in Å).
Figure 2: Time-dependent 1H NMR spectra of 2, 3 and 4 (13-H multiplets region). The experiments were performe...
Figure 3: Interconversion kinetics of compounds 2 (blue), 3 (orange) and 4 (grey).
Figure 4: Modelling-derived structure of 3 showing key nOe interactions (calculated distances in Å).
Figure 5: Modelling-derived structure of compound 4 showing key nOe interactions (calculated distances in Å).
Figure 6: Comparison of the spiroketal ring system stereochemistry and conformations in compounds 2–4.
Figure 7: Overlay of the computed structures of 3 (green) and 4 (blue).
Scheme 2: Postulated mechanism for the formation of compounds 2–4.
Come-back of phenanthridine and phenanthridinium derivatives in the 21st century
- Lidija-Marija Tumir,
- Marijana Radić Stojković and
- Ivo Piantanida
Beilstein J. Org. Chem. 2014, 10, 2930–2954, doi:10.3762/bjoc.10.312
- various DNA and RNA. The ability of ethidium bromide analogues to inhibit the HIV-1 Rev–Rev Response Element (RRE) interaction, as well as their affinity to calf thymus (ct)DNA was analysed. One derivative (Figure 2, 1) displayed an enhanced affinity for HIV-1 RRE and a lower DNA affinity (i.e., lower
- respect to other nucleotides. In addition, the observed selectivity towards poly(G) and poly(A) can be beneficial in biological applications for instance to influence the mRNA-function via binding to the poly(A) tail [62][63][64] and inhibition of the HIV-1 replication by targeting recognition of the
Graphical Abstract
Scheme 1: The Grignard-based synthesis of 6-alkyl phenanthridine.
Scheme 2: Radical-mediated synthesis of 6-arylphenanthridine [14].
Scheme 3: A t-BuO• radical-assisted homolytic aromatic substitution mechanism proposed for the conversion of ...
Scheme 4: Synthesis of 5,6-unsubstituted phenanthridine starting from 2-iodobenzyl chloride and aniline [17].
Scheme 5: Phenanthridine synthesis initiated by UV-light irradiation photolysis of acetophenone O-ethoxycarbo...
Scheme 6: PhI(OAc)2-mediated oxidative cyclization of 2-isocyanobiphenyls with CF3SiMe3 [19,20].
Scheme 7: Targeting 6-perfluoroalkylphenanthridines [21,22].
Scheme 8: Easily accessible biphenyl isocyanides reacting under mild conditions (room temp., visible light ir...
Scheme 9: Microwave irradiation of Diels–Alder adduct followed by UV irradiation of dihydrophenanthridines yi...
Scheme 10: A representative palladium catalytic cycle.
Scheme 11: The common Pd-catalyst for the biphenyl conjugation results simultaneously in picolinamide-directed...
Scheme 12: Pd(0)-mediated cyclisation of imidoyl-selenides forming 6-arylphenanthridine derivatives [16]. The inse...
Scheme 13: Palladium-catalysed phenanthridine synthesis.
Scheme 14: Aerobic domino Suzuki coupling combined with Michael addition reaction in the presence of a Pd(OAc)2...
Scheme 15: Rhodium-catalysed alkyne [2 + 2 + 2] cycloaddition reactions [36].
Scheme 16: The O-acetyloximes derived from 2′-arylacetophenones underwent N–O bond cleavage and intramolecular ...
Scheme 17: C–H arylation with aryl chloride in the presence of a simple diol complex with KOt-Bu (top) [39]; for s...
Scheme 18: The subsequent aza-Claisen rearrangement, ring-closing enyne metathesis and Diels–Alder reaction – ...
Scheme 19: Phenanthridine central-ring cyclisation with simultaneous radical-driven phosphorylation [42].
Scheme 20: Three component reaction yielding the benzo[a]phenanthridine core in excellent yields [44].
Scheme 21: a) Reaction of malononitrile and 1,3-indandione with BEP to form the cyclised DPP products; b) pH c...
Figure 1: Schematic presentation of the intercalative binding mode by the neighbour exclusion principle and i...
Figure 2: Urea and guanidine derivatives of EB with modified DNA interactions [57].
Figure 3: Structure of mono- (3) and bis-biguanide (4) derivative. Fluorescence (y-axis normalised to startin...
Scheme 22: Bis-phenanthridinium derivatives (5–7; inert aliphatic linkers, R = –(CH2)4– or –(CH2)6–): rigidity...
Figure 4: Series of amino acid–phenanthridine building blocks (general structure 10; R = H; Gly) and peptide-...
Figure 5: General structure of 45 bis-ethidium bromide analogues. Reproduced with permission from [69]. Copyright...
Scheme 23: Top: Recognition of poly(U) by 12 and ds-polyAH+ by 13; bottom: Recognition of poly(dA)–poly(dT) by ...
Figure 6: The bis-phenanthridinium–adenine derivative 15 (LEFT) showed selectivity towards complementary UMP;...
Figure 7: The neomycin–methidium conjugate targeting DNA:RNA hybrid structures [80].
Figure 8: Two-colour RNA intercalating probe for cell imaging applications: Left: Chemical structure of EB-fl...
Figure 9: The ethidium bromide nucleosides 17 (top) and 18 (bottom). DNA duplex set 1 and 2 (E = phenanthridi...
Figure 10: Left: various DNA duplexes; DNA1 and DNA2 used to study the impact on the adjacent basepair type on...
Figure 11: Structure of 4,9-DAP derivative 19; Rright: MIAPaCa-2 cells stained with 10 μM 19 after 60 and 120 ...
Figure 12: Examples of naturally occurring phenanthridine analogues.
Encapsulation of biocides by cyclodextrins: toward synergistic effects against pathogens
- Véronique Nardello-Rataj and
- Loïc Leclercq
Beilstein J. Org. Chem. 2014, 10, 2603–2622, doi:10.3762/bjoc.10.273
Graphical Abstract
Scheme 1: Principle of resistance mechanisms through selection of the most resistant micro-organism.
Figure 1: Chemical structure of carbendazim.
Scheme 2: Chemical structure of benomyl and its decomposition in aqueous solution.
Figure 2: Chemical structure of enilconazole.
Figure 3: Chemical structure of chloramidophos.
Scheme 3: The complex problem of pentachlorophenol (PCP) degradation.
Figure 4: Chemical structure of DCPE.
Figure 5: Chemical structures of some biocides used in [59].
Figure 6: Chemical structure of miconazole nitrate.
Figure 7: Chemical structures of triclosan and butylparaben.
Figure 8: Chemical structure of ciprofloxacin hydrochloride.
Figure 9: Chemical structure of benzethonium chloride.
Figure 10: Chemical structure of benzalkonium chlorides.
Scheme 4: Multiple equilibria of CD with benzalkonium chloride (BZK) and fluorometholone.
Scheme 5: Competition between co-micellization and biocidal activity observed for didecyldimethylammonium chl...
Scheme 6: Proposed antimicrobial mechanism of encapsulated didecyldimethylammonium chloride by CDs: (1) diffu...
Scheme 7: Inhibition of co-micellization process observed for didecyldimethylammonium chloride, octaethyleneg...
Scheme 8: Schematic representation of biocide release from a chemically cross-linked CD network.
Scheme 9: Proposed Trojan horse mechanism of silver nanoparticles capped by β-CD.
Scheme 10: Proposed mechanism of copper nanoparticles immobilized on carbon nanotube and embedded in water-ins...
Scheme 11: Advantages and drawback of the physicochemical and biopharmaceutical properties of CDs/biocides inc...
Glycosystems in nanotechnology: Gold glyconanoparticles as carrier for anti-HIV prodrugs
- Fabrizio Chiodo,
- Marco Marradi,
- Javier Calvo,
- Eloisa Yuste and
- Soledad Penadés
Beilstein J. Org. Chem. 2014, 10, 1339–1346, doi:10.3762/bjoc.10.136
- virus type-1 (HIV-1) [1] continues to be a major leading pandemic disease worldwide with approximately 34 million people living with HIV [2]. Due to its incredible genetic variance and the specificity for CD4+ T cells, this virus is responsible for 800.000 deaths per year. In addition to sexual
- related to HIV envelope [18]. GNPs coated with oligomannosides of the gp120 (manno-GNPs) were able to inhibit the DC-SIGN-mediated HIV-1 trans-infection of human T-cells [19] and gold glyconanoparticles coated with sulfated ligands showed to interfere with the adhesion/fusion of HIV during its entry [20
- nucleoside substrates acting as chain terminators in the DNA polymerisation reaction catalyzed by HIV-1 RT [3]. Both drugs were transformed in ester derivatives to prepare the GNPs. The pH-mediated release of the drugs from the GNPs surface was evaluated and cellular experiments demonstrated that abacavir
Graphical Abstract
Figure 1: The prepared lamivudine (3TC) and abacavir (ABC) potential prodrugs and the corresponding 3TC- and ...
Figure 2: Time course release of free 3TC and ABC from the corresponding GNPs in 1 N HCl, detected by HPLC–MS...
Figure 3: Cellular experiments: The two graphs show the percentage of luciferase activity decrease in the pre...
Isocyanide-based multicomponent reactions towards cyclic constrained peptidomimetics
- Gijs Koopmanschap,
- Eelco Ruijter and
- Romano V.A. Orru
Beilstein J. Org. Chem. 2014, 10, 544–598, doi:10.3762/bjoc.10.50
- - [31], elastase- [32][33][34][35], and HIV-1 protease [36] and papain [37]. For the design of β-lactams, the Staudinger reaction involving a [2 + 2] cycloaddition of ketenes and imines is the most common method used [38]. However, Ugi reactions starting form β-amino acids are also described. In 2002
- of amide bonds by 1,2,3-triazoles, especially the 1,4-disubstituted isomer, provided a wide variety of biological active peptidomimetics. Peptidomimetics containing these triazole cores can serve as blood components [77], anticancer medications [78], inhibitors of cysteine [79] and HIV-1 proteases
- ]. Several studies have revealed the bio-similarity of triazoles with amide bonds. For example, X-ray studies towards triazole based-mimics of the HIV-1 protease inhibitor amprenavir showed an equivalent binding mode with the protease active site as compared to the amide-bond inhibitor [81][83][84
Graphical Abstract
Scheme 1: The proposed mechanism of the Passerini reaction.
Scheme 2: The PADAM-strategy to α-hydroxy-β-amino amide derivatives 7. An additional oxidation provides α-ket...
Scheme 3: The general accepted Ugi-mechanism.
Scheme 4: Three commonly applied Ugi/cyclization approaches. a) UDC-process, b) UAC-sequence, c) UDAC-combina...
Scheme 5: Ugi reaction that involves the condensation of Armstrong’s convertible isocyanide.
Scheme 6: Mechanism of the U-4C-3CR towards bicyclic β-lactams.
Scheme 7: The Ugi 4C-3CR towards oxabicyclo β-lactams.
Scheme 8: Ugi MCR between an enantiopure monoterpene based β-amino acid, aldehyde and isocyanide resulting in...
Scheme 9: General MCR for β-lactams in water.
Scheme 10: a) Ugi reaction for β-lactam-linked peptidomimetics. b) Varying the β-amino acid resulted in β-lact...
Scheme 11: Ugi-4CR followed by a Pd-catalyzed Sn2 cyclization.
Scheme 12: Ugi-3CR of dipeptide mimics from 2-substituted pyrrolines.
Scheme 13: Joullié–Ugi reaction towards 2,5-disubstituted pyrrolidines.
Scheme 14: Further elaboration of the Ugi-scaffold towards bicyclic systems.
Scheme 15: Dihydroxyproline derivatives from an Ugi reaction.
Scheme 16: Diastereoselective Ugi reaction described by Banfi and co-workers.
Scheme 17: Similar Ugi reaction as in Scheme 16 but with different acids and two chiral isocyanides.
Scheme 18: Highly diastereoselective synthesis of pyrrolidine-dipeptoids via a MAO-N/MCR-procedure.
Scheme 19: MAO-N/MCR-approach towards the hepatitis C drug telaprevir.
Scheme 20: Enantioselective MAO-U-3CR procedure starting from chiral pyrroline 64.
Scheme 21: Synthesis of γ-lactams via an UDC-sequence.
Scheme 22: Utilizing bifunctional groups to provide bicyclic γ-lactam-ketopiperazines.
Scheme 23: The Ugi reaction provided both γ- as δ-lactams depending on which inputs were used.
Scheme 24: The sequential Ugi/RCM with olefinic substrates provided bicyclic lactams.
Scheme 25: a) The structural and dipole similarities of the triazole unit with the amide bond. b) The copper-c...
Scheme 26: The Ugi/Click sequence provided triazole based peptidomimetics.
Scheme 27: The Ugi/Click reaction as described by Nanajdenko.
Scheme 28: The Ugi/Click-approach by Pramitha and Bahulayan.
Scheme 29: The Ugi/Click-combination by Niu et al.
Scheme 30: Triazole linked peptidomimetics obtained from two separate MCRs and a sequential Click reaction.
Scheme 31: Copper-free synthesis of triazoles via two MCRs in one-pot.
Scheme 32: The sequential Ugi/Paal–Knorr reaction to afford pyrazoles.
Scheme 33: An intramolecular Paal–Knorr condensation provided under basic conditions pyrazolones.
Scheme 34: Similar cyclization performed under acidic conditions provided pyrazolones without the trifluoroace...
Scheme 35: The Ugi-4CR towards 2,4-disubstituted thiazoles.
Scheme 36: Solid phase approach towards thiazoles.
Scheme 37: Reaction mechanism of formation of thiazole peptidomimetics containing an additional β-lactam moiet...
Scheme 38: The synthesis of the trisubstituted thiazoles could be either performed via an Ugi reaction with pr...
Scheme 39: Performing the Ugi reaction with DMB-protected isocyanide gave access to either oxazoles or thiazol...
Scheme 40: Ugi/cyclization-approach towards 2,5-disubstituted thiazoles. The Ugi reaction was performed with d...
Scheme 41: Further derivatization of the thiazole scaffold.
Scheme 42: Three-step procedure towards the natural product bacillamide C.
Scheme 43: Ugi-4CR to oxazoles reported by Zhu and co-workers.
Scheme 44: Ugi-based synthesis of oxazole-containing peptidomimetics.
Scheme 45: TMNS3 based Ugi reaction for peptidomimics containing a tetrazole.
Scheme 46: Catalytic cycle of the enantioselective Passerini reaction towards tetrazole-based peptidomimetics.
Scheme 47: Tetrazole-based peptidomimetics via an Ugi reaction and a subsequent sigmatropic rearrangement.
Scheme 48: Resin-bound Ugi-approach towards tetrazole-based peptidomimetics.
Scheme 49: Ugi/cyclization approach towards γ/δ/ε-lactam tetrazoles.
Scheme 50: Ugi-3CR to pipecolic acid-based peptidomimetics.
Scheme 51: Staudinger–Aza-Wittig/Ugi-approach towards pipecolic acid peptidomimetics.
Figure 1: The three structural isomers of diketopiperazines. The 2,5-DKP isomer is most common.
Scheme 52: UDC-approach to obtain 2,5-DKPs, either using Armstrong’s isocyanide or via ethylglyoxalate.
Scheme 53: a) Ugi reaction in water gave either 2,5-DKP structures or spiro compounds. b) The Ugi reaction in ...
Scheme 54: Solid-phase approach towards diketopiperazines.
Scheme 55: UDAC-approach towards DKPs.
Scheme 56: The intermediate amide is activated as leaving group by acid and microwave assisted organic synthes...
Scheme 57: UDC-procedure towards active oxytocin inhibitors.
Scheme 58: An improved stereoselective MCR-approach towards the oxytocin inhibitor.
Scheme 59: The less common Ugi reaction towards DKPs, involving a Sn2-substitution.
Figure 2: Spatial similarities between a natural β-turn conformation and a DKP based β-turn mimetic [158].
Scheme 60: Ugi-based syntheses of bicyclic DKPs. The amine component is derived from a coupling between (R)-N-...
Scheme 61: Ugi-based synthesis of β-turn and γ-turn mimetics.
Figure 3: Isocyanide substituted 3,4-dihydropyridin-2-ones, dihydropyridines and the Freidinger lactams. Bio-...
Scheme 62: The mechanism of the 4-CR towards 3,4-dihydropyridine-2-ones 212.
Scheme 63: a) Multiple MCR-approach to provide DHP-peptidomimetic in two-steps. b) A one-pot 6-CR providing th...
Scheme 64: The MCR–alkylation–MCR procedure to obtain either tetrapeptoids or depsipeptides.
Scheme 65: U-3CR/cyclization employing semicarbazone as imine component gave triazine based peptidomimetics.
Scheme 66: 4CR towards triazinane-diones.
Scheme 67: The MCR–alkylation–IMCR-sequence described by our group towards triazinane dione-based peptidomimet...
Scheme 68: Ugi-4CR approaches followed by a cyclization to thiomorpholin-ones (a) and pyrrolidines (b).
Scheme 69: UDC-approach for benzodiazepinones.
Scheme 70: Ugi/Mitsunobu sequence to BDPs.
Scheme 71: A UDAC-approach to BDPs with convertible isocyanides. The corresponding amide is cleaved by microwa...
Scheme 72: microwave assisted post condensation Ugi reaction.
Scheme 73: Benzodiazepinones synthesized via the post-condensation Ugi/ Staudinger–Aza-Wittig cyclization.
Scheme 74: Two Ugi/cyclization approaches utilizing chiral carboxylic acids. Reaction (a) provided the product...
Scheme 75: The mechanism of the Gewald-3CR includes three base-catalysed steps involving first a Knoevnagel–Co...
Scheme 76: Two structural 1,4-thienodiazepine-2,5-dione isomers by U-4CR/cyclization.
Scheme 77: Tetrazole-based diazepinones by UDC-procedure.
Scheme 78: Tetrazole-based BDPs via a sequential Ugi/hydrolysis/coupling.
Scheme 79: MCR synthesis of three different tricyclic BPDs.
Scheme 80: Two similar approaches both involving an Ugi reaction and a Mitsunobu cyclization.
Scheme 81: Mitsunobu–Ugi-approach towards dihydro-1,4-benzoxazepines.
Scheme 82: Ugi reaction towards hetero-aryl fused 5-oxo-1,4-oxazepines.
Scheme 83: a) Ugi/RCM-approach towards nine-membered peptidomimetics b) Sequential peptide-coupling, deprotect...
Scheme 84: Ugi-based synthesis towards cyclic RGD-pentapeptides.
Scheme 85: Ugi/MCR-approach towards 12–15 membered macrocycles.
Scheme 86: Stereoselective Ugi/RCM approach towards 16-membered macrocycles.
Scheme 87: Passerini/RCM-sequence to 22-membered macrocycles.
Scheme 88: UDAC-approach towards 12–18-membered depsipeptides.
Figure 4: Enopeptin A with its more active derivative ADEP-4.
Scheme 89: a) The Joullié–Ugi-approach towards ADEP-4 derivatives b) Ugi-approach for the α,α-dimethylated der...
Scheme 90: Ugi–Click-strategy for 15-membered macrocyclic glyco-peptidomimetics.
Scheme 91: Ugi/Click combinations provided macrocycles containing both a triazole and an oxazole moiety.
Scheme 92: a) A solution-phase procedure towards macrocycles. b) Alternative solid-phase synthesis as was repo...
Scheme 93: Ugi/cyclization towards cyclophane based macrocycles.
Scheme 94: PADAM-strategy towards eurystatin A.
Scheme 95: PADAM-approach for cyclotheanamide.
Scheme 96: A triple MCR-approach affording RGD-pentapeptoids.
Scheme 97: Ugi-MiBs-approach towards peptoid macrocycles.
Scheme 98: Passerini-based MiB approaches towards macrocycles 345 and 346.
Scheme 99: Macrocyclic peptide formation by the use of amphoteric aziridine-based aldehydes.
Investigating the continuous synthesis of a nicotinonitrile precursor to nevirapine
- Ashley R. Longstreet,
- Suzanne M. Opalka,
- Brian S. Campbell,
- B. Frank Gupton and
- D. Tyler McQuade
Beilstein J. Org. Chem. 2013, 9, 2570–2578, doi:10.3762/bjoc.9.292
- ; nicotinonitriles; Introduction Nevirapine (3) was the first commercially available non-nucleoside reverse transcriptase inhibitor (NNRTI), and has remained an important medicine in the management of human immunodeficiency virus (HIV) [1][2]. Nevirapine combined with lamivudine (3TC) and azidothymidine (AZT) or
Graphical Abstract
Figure 1: The estimated demand of for nevirapine until 2015 [6].
Scheme 1: Commercial building blocks to nevirapine.
Scheme 2: a) Current commercial process to CAPIC and b) newly developed batch synthesis to CAPIC and its brom...
Scheme 3: Proposed synthesis to 2-bromo-4-methylnicotinonitrile using a continuous approach with the consider...
Figure 2: a) Flow scheme to produce the enamine intermediate 5 from isopropylidenemalononitrile (4) (see Supporting Information File 1 for...
Scheme 4: Flow scheme to produce the enamine 5 starting from acetone and malononitrile (See Supporting Information File 1 for details).
Figure 3: Comparing the long-term stability of the Al2O3 and 3 Å MS columns when the Al2O3 column temperature...
Scheme 5: Several byproducts were observed when producing 5 starting from acetone and malononitrile. 7 is for...
Scheme 6: Flow scheme to produce 2-bromo-4-methylnicotinonitrile (6b) in 81% yield from 4 with a 1 M concentr...
Scheme 7: Reactor scheme for the continuous synthesis of 2-bromo-4-methylnicotinonitrile (6b) with an average...
Synthesis of the spiroketal core of integramycin
- Evgeny. V. Prusov
Beilstein J. Org. Chem. 2013, 9, 2446–2450, doi:10.3762/bjoc.9.282
- ; hydrozirconation; natural products; spiroketals; total synthesis; Findings Integramycin is a polyketide natural product isolated from Actinoplanes sp. by the Singh group at Merck [1] (Figure 1). The compound was found to inhibit HIV-1 integrase coupled strand transfer reactions with IC50 values of 3 and 4 μM
Graphical Abstract
Figure 1: Structure of integramycin (1) and its producing organism, Actinoplanes sp. (Photo: J. Wink, HZI, Mi...
Figure 2: Retrosynthetic analysis of integramycin.
Scheme 1: Synthesis of the aromatic subunit.
Scheme 2: Sharpless epoxidation/Myers alkylation approach to the C16–C22 carboxylic acid fragment.
Scheme 3: Coupling of the fragments and spiroketalization.
The chemistry of isoindole natural products
- Klaus Speck and
- Thomas Magauer
Beilstein J. Org. Chem. 2013, 9, 2048–2078, doi:10.3762/bjoc.9.243
- , Vedejs), the convergent approach reported by Myers allows a modular entry to diverse members of the cytochalasin alkaloid family [68]. As proof of concept, the macrolactone cytochalasin B (52) and the carbocyclic cytochalasin L-696,474 (78), a potent HIV-1 protease inhibitor [69][70][71][72], were
- interesting biological properties, such as high antiviral activity (156) [141], inhibition of the HIV-1 protease (157) [132], antibacterial and antifungal activities (159–160) [133] or neuritogenic properties (161) [134]. So far, only a few total syntheses were accomplished and the exact biosynthetic pathways
Graphical Abstract
Figure 1: a) Structural features and b) selected examples of non-natural congeners.
Scheme 1: Synthesis of isoindole 18.
Scheme 2: Staining amines with 1,4-diketone 19 (R = H).
Figure 2: Representative members of the indolocarbazole alkaloid family.
Figure 3: Staurosporine (26) bound to the adenosine-binding pocket [19] (from pdb1stc).
Figure 4: Structure of imatinib (34) and midostaurin (35).
Scheme 3: Biosynthesis of staurosporine (26).
Scheme 4: Wood’s synthesis of K-252a via the common intermediate 48.
Scheme 5: Synthesis of 26, 27, 49 and 50 diverging from the common intermediate 48.
Figure 5: Selected members of the cytochalasan alkaloid family.
Scheme 6: Biosynthesis of chaetoglobosin A (57) [56].
Scheme 7: Synthesis of cytochalasin D (70) by Thomas [63].
Scheme 8: Synthesis of L-696,474 (78).
Scheme 9: Synthesis of aldehyde 85 (R = TBDPS).
Scheme 10: Synthesis of (+)-aspergillin PZ (79) by Tanis.
Figure 6: Representative Berberis alkaloids.
Scheme 11: Proposed biosynthetic pathway to chilenine (93).
Scheme 12: Synthesis of magallanesine (97) by Danishefsky [84].
Scheme 13: Kurihara’s synthesis of magallanesine (85).
Scheme 14: Proposed biosynthesis of 113, 117 and 125.
Scheme 15: DNA lesion caused by aristolochic acid I (117) [102].
Scheme 16: Snieckus’ synthesis of piperolactam C (131).
Scheme 17: Synthesis of aristolactam BII (104).
Figure 7: Representative cularine alkaloids.
Scheme 18: Proposed biosynthesis of 136.
Scheme 19: The syntheses of 136 and 137 reported by Castedo and Suau.
Scheme 20: Synthesis of 136 by Couture.
Figure 8: Representative isoindolinone meroterpenoids.
Scheme 21: Postulated biosynthetic pathway for the formation of 156 (adopted from George) [143].
Scheme 22: Synthesis of stachyflin (156) by Katoh [144].
Figure 9: Selected examples of spirodihydrobenzofuranlactams.
Scheme 23: Synthesis of stachybotrylactam I (157).
Scheme 24: Synthesis of pestalachloride A (193) by Schmalz.
Scheme 25: Proposed mechanism for the BF3-catalyzed metal-free carbonyl–olefin metathesis [149].
Scheme 26: Preparation of the isoindoline core of muironolide A (204).
Scheme 27: Proposed biosynthesis of 208.
Scheme 28: Model for the biosynthesis of 215 and 217.
Scheme 29: Synthesis of lactonamycin (215) and lactonamycin Z (217).
Figure 10: Hetisine alkaloids 225–228.
Scheme 30: Biosynthetic proposal for the formation of the hetisine core [167].
Scheme 31: Synthesis of nominine (225).
