Synthesis of 2H-azirine-2,2-dicarboxylic acids and their derivatives

• Anastasiya V. Agafonova,
• Mikhail S. Novikov and
• Alexander F. Khlebnikov

Beilstein J. Org. Chem. 2024, 20, 3191–3197, doi:10.3762/bjoc.20.264

• chlorides have been developed. Keywords: azirine-2,2-dicarboxamides; azirine-2,2-dicarboxylic acids; isomerization; isoxazoles; Introduction The isomerization of isoxazoles, containing a heteroatomic substituent at C5, to 2H-azirines is a powerful method for the preparation of 2H-azirine-2-carboxylic acid

• derivatives [1]. In particular, the catalytic isomerization of 5-chloroisoxazoles allows the generation of azirine-2-carbonyl chlorides, which can be easily converted into a variety of azirine-2-carboxylic acid derivatives by reactions with nucleophilic reagents. Using this approach, numerous 2-(1H-pyrazol-1

• -carboxylic acid derivatives are not only valuable synthetic building blocks [3][4][5][6][7][8][9][10][11] but also show useful biological activities [12][13][14][15][16][17][18]. Although many 2,2-bifunctionalized azirines have been synthesized [3][4][5][6][7][8][9][10][11], the synthesis of only one 2H

Synthesis of extended fluorinated tripeptides based on the tetrahydropyridazine scaffold

• Thierry Milcent,
• Pascal Retailleau,
• Benoit Crousse and
• Sandrine Ongeri

Beilstein J. Org. Chem. 2024, 20, 3174–3181, doi:10.3762/bjoc.20.262

• electronic and structural properties of the fluorinated groups (CF3 or CF2H) and the geometric constraints due to its partially unsaturated cycle, which could help in the design of peptidomimetics. To our knowledge, only a few publications report the synthesis of tetrahydropyridazines with a carboxylic acid

Hypervalent iodine-mediated intramolecular alkene halocyclisation

• Charu Bansal,
• Oliver Ruggles,
• Albert C. Rowett and
• Alastair J. J. Lennox

Beilstein J. Org. Chem. 2024, 20, 3113–3133, doi:10.3762/bjoc.20.258

• enough to displace the iodane to form the oxonium species A. When the carboxylic acid is used, the oxygen in the lactone intermediate is less reactive and so substitution of the iodane by fluoride is more favourable and the branched product is formed. In addition to aminofluorination, Szabó also reported

• , iodoetherification of 2,2-diphenyl-4-penten-1-carboxylic acid (47') and 2,2-diphenyl-4-penten-1-ol (47) was reported by Liu and Li in 2014 (Scheme 26) [30]. The authors reported using PhI(OAc)2 and KI in the synthesis of iodonated γ-butyrolactone 83 and iodomethyltetrahydrofuran 82 in excellent yields (Scheme 44

• . Iodoetherification of 2,2-diphenyl-4-penten-1-carboxylic acid (47’) and 2,2-diphenyl-4-penten-1-ol (47). Synthesis of 5-iodomethyl-2-oxazolines. Synthesis of chiral iodinated morpholines. aFrom the ʟ-form of the amino acid starting material. The dr values were determined by 1H NMR given in parentheses

Cyclodextrin-based rotaxanes for polymer materials: challenge on simultaneous realization of inexpensive production and defined structures

• Yosuke Akae

Beilstein J. Org. Chem. 2024, 20, 3026–3049, doi:10.3762/bjoc.20.252

• , such as carboxylic acid or sulfonic acid groups must be integrated into the system, thus limiting the flexibility of the molecular design of rotaxane. Even after appropriately integrating these hydrophilic groups into the molecular design, the yield of the rotaxanation step is likely to be as low as 10

• , most of their rotaxane structures required a complicated multistep synthesis as well as the introduction of polar substituents, such as carboxylic acid or sulfonic acid groups, to generate a water-soluble system, and these prevent the direct application of those frameworks to polymer systems. As the

Advances in radical peroxidation with hydroperoxides

• Oleg V. Bityukov,
• Pavel Yu. Serdyuchenko,
• Andrey S. Kirillov,
• Gennady I. Nikishin,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2024, 20, 2959–3006, doi:10.3762/bjoc.20.249

• -AcrClO4 as the photocatalyst has been disclosed (Scheme 24) [67]. According to the authors, the irradiation of the photocatalyst (Acr+-Mes) A with a blue LED leads to the excited state (Acr·-Mes·+) B. The aliphatic carboxylic acid 66 is converted by deprotonation to the corresponding carboxylate, which is

• to generate the iodoperoxidate intermediate C. Finally, nucleophilic addition of anion of carboxylic acid to intermediate C generates the desired product 216. Based on the iodination/peroxidation strategy the approach to α-hydroxy-β-peroxyethylarenes 219 and α-alkoxy-β-peroxyethylarenes 218 from

Synthesis of fluorinated acid-functionalized, electron-rich nickel porphyrins

• Mike Brockmann,
• Jonas Lobbel,
• Lara Unterriker and
• Rainer Herges

Beilstein J. Org. Chem. 2024, 20, 2954–2958, doi:10.3762/bjoc.20.248

• Mike Brockmann Jonas Lobbel Lara Unterriker Rainer Herges Otto Diels-Institute of Organic Chemistry, Christian-Albrechts-Universität zu Kiel, Otto-Hahn-Platz 4, 24118 Kiel, Germany 10.3762/bjoc.20.248 Abstract In this study, novel fluorinated carboxylic acid esters of the generic structure TfO

Synthesis of tricarbonylated propargylamine and conversion to 2,5-disubstituted oxazole-4-carboxylates

• Kento Iwai,
• Akari Hikasa,
• Kotaro Yoshioka,
• Shinki Tani,
• Kazuto Umezu and
• Nagatoshi Nishiwaki

Beilstein J. Org. Chem. 2024, 20, 2827–2833, doi:10.3762/bjoc.20.238

• acid amides and acetylides, respectively. When adduct 4 was treated with a base or ammonium acetate, ring closure proceeded to form a five-membered ring, accompanied by the elimination of the ethoxycarbonyl group. 2,5-Disubstituted oxazole-4-carboxylic acid derivatives are frequently found in

A review of recent advances in electrochemical and photoelectrochemical late-stage functionalization classified by anodic oxidation, cathodic reduction, and paired electrolysis

• Nian Li,
• Ruzal Sitdikov,
• Ajit Prabhakar Kale,
• Joost Steverlynck,
• Bo Li and
• Magnus Rueping

Beilstein J. Org. Chem. 2024, 20, 2500–2566, doi:10.3762/bjoc.20.214

• constant voltage (CV) conditions and light irradiation under a nitrogen atmosphere. This method demonstrates broad compatibility with various functional groups and complex substrates, including alcohol, carboxylic acid, esters, alkyl chloride, and tosylate groups. Notably, the LSF of compounds such as

HFIP as a versatile solvent in resorcin[n]arene synthesis

• Hormoz Khosravi,
• Valeria Stevens and
• Raúl Hernández Sánchez

Beilstein J. Org. Chem. 2024, 20, 2469–2475, doi:10.3762/bjoc.20.211

• described in the introduction (Scheme 1a and b) [56][58][59][63][66][80][84][85][86][87][88]. Furthermore, we successfully synthesized carboxylic acid-containing resorcin[4]arenes 1o–s employing HFIP under an optimized reaction time of 48 hours. Compounds 1o–s are reported here for the first time. Their

• , chlorinated species 1h and 1i, and carboxylic acid-containing 1s, developed high quality crystals from standing solutions in dimethyl sulfoxide for 1h and 1i, and methanol for 1s. Their molecular crystal structures were determined and are shown in Figure 1b displaying the classic cone conformation for both

• translated to the formation of other macrocycles as long as they share a similar reaction mechanism. (a) Control experiment testing deiodination of 2-iodoresorcinol. (b) Molecular crystal structure of chlorinated resorcin[4]arenes 1h and 1i, and carboxylic acid-containing 1s at 100 K. Thermal ellipsoids are

Facile preparation of fluorine-containing 2,3-epoxypropanoates and their epoxy ring-opening reactions with various nucleophiles

• Yutaro Miyashita,
• Sae Someya,
• Tomoko Kawasaki-Takasuka,
• Tomohiro Agou and
• Takashi Yamazaki

Beilstein J. Org. Chem. 2024, 20, 2421–2433, doi:10.3762/bjoc.20.206

• succeeded by the usual hydrogenolysis to furnish the carboxylic acid anti,syn-8a in 79% isolated yield and the lactone anti,syn-7b was recovered in 13% yield (Scheme 4) which was considered to be the reflection of the original composition of anti,syn-7a and -7b. The relative stereochemistry of anti,syn-8a

Efficient one-step synthesis of diarylacetic acids by electrochemical direct carboxylation of diarylmethanol compounds in DMSO

• Hisanori Senboku and
• Mizuki Hayama

Beilstein J. Org. Chem. 2024, 20, 2392–2400, doi:10.3762/bjoc.20.203

• acid 2c and defluorinated carboxylic acid 2a. Fluorine-containing starting material 1c and defluorinated diphenylmethanol (1a) were detected by 1H NMR analysis. At the same time, it is presently unclear whether 2a was produced in a carboxylation–defluorination or defluorination–carboxylation sequence

• xanthenol (1k) provided xanthene-9-carboxylic acid (2k) in an excellent yield of 90%. Phenyl(thiophen-2-yl)acetic acid (2l) could also be synthesized in an excellent yield of 92% yield by electrochemical carboxylation of phenyl(thiophen-2-yl)methanol (1l). Although a wide range of substrates was shown to be

• triphenylmethanol (1n) was subjected to the electrochemical carboxylation, a small amount of carboxylic acid was obtained as a complex mixture. However, in the 1H NMR spectrum of the organic component after extraction with aqueous base, we observed a singlet at δ 5.55 ppm, which could be assigned to the methine

Stereoselective mechanochemical synthesis of thiomalonate Michael adducts via iminium catalysis by chiral primary amines

• Michał Błauciak,
• Dominika Andrzejczyk,
• Błażej Dziuk and
• Rafał Kowalczyk

Beilstein J. Org. Chem. 2024, 20, 2313–2322, doi:10.3762/bjoc.20.198

• enhancing the reactivity of a relatively inert acceptor does not necessarily lead to increased reaction rates, involves the use of more reactive nucleophiles. In this context, varying the stabilization energy of carboxylic acid derivatives by switching from oxoesters to thioesters is the significant

Deuterated reagents in multicomponent reactions to afford deuterium-labeled products

• Kevin Schofield,
• Shayna Maddern,
• Yueteng Zhang,
• Grace E. Mastin,
• Rachel Knight,
• Wei Wang,
• James Galligan and
• Christopher Hulme

Beilstein J. Org. Chem. 2024, 20, 2270–2279, doi:10.3762/bjoc.20.195

• scope of reactivity and determination of deuterium retention using a combination of deuterated aldehydes, [D1]-, and/or [D2]-isocyanides. We began with the venerable Ugi 4-component reaction (Ugi-4CR), first reported by Ivar Ugi in 1959 [28]. The Ugi-4CR utilizes an amine, carbonyl, carboxylic acid, and

• converted to a carboxylic acid via typical saponification conditions without loss of deuterium (See Supporting Information File 1 for conditions). Biginelli reaction products, no deuterium scrambling was observed. Six site-specific deuterated Biginelli products are revealed in good yield with no deuterium

Natural resorcylic lactones derived from alternariol

• Joachim Podlech

Beilstein J. Org. Chem. 2024, 20, 2171–2207, doi:10.3762/bjoc.20.187

• lack the carboxylic acid are included (Figure 13). Altenusin (47) is biosynthetically obtained through reductive cleavage of 4-hydroxyalternariol (19) and it was already mentioned in one of the first reports on Alternaria metabolites when it was isolated from Alternaria tenuis (synonymous to A

Computational toolbox for the analysis of protein–glycan interactions

• Ferran Nieto-Fabregat,
• Maria Pia Lenza,
• Angela Marseglia,
• Cristina Di Carluccio,
• Antonio Molinaro,
• Alba Silipo and
• Roberta Marchetti

Beilstein J. Org. Chem. 2024, 20, 2084–2107, doi:10.3762/bjoc.20.180

• are able to recognise carboxylic acid and sulphate groups along glycosaminoglycan chains using clusters of positively charged amino acids [33], also mediate a wide variety of cell–cell and cell–pathogen communication, controlling immune cell functions, and overseeing cellular trafficking [34]. Another

Multicomponent syntheses of pyrazoles via (3 + 2)-cyclocondensation and (3 + 2)-cycloaddition key steps

• Ignaz Betcke,
• Alissa C. Götzinger,
• Maryna M. Kornet and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2024, 20, 2024–2077, doi:10.3762/bjoc.20.178

• -dicarbonyl compounds and their one-pot transformation pave the way for MCR syntheses of pyrazoles. 1,3-Dicarbonyl compounds can, for example, be generated in situ from enolates and carboxylic acid chlorides. They can be converted to the corresponding pyrazoles 1 in a consecutive multicomponent reaction with

Allostreptopyrroles A–E, β-alkylpyrrole derivatives from an actinomycete Allostreptomyces sp. RD068384

• Marwa Elsbaey,
• Naoya Oku,
• Mohamed S. A. Abdel-Mottaleb and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2024, 20, 1981–1987, doi:10.3762/bjoc.20.174

• : Allostreptomyces; β-alkylpyrrole; conformer; cytotoxic; DFT; 4-formylpyrrole-2-carboxylic acid; Introduction β-Alkylpyrroles are key structural motifs in biomolecules and functional organic materials [1]. For instance, β-alkylpyrroles are the main building blocks for the life-essential tetrapyrrole pigments

• many marine natural products [6][7], pyrroles substituted with long hydrocarbon chains (pyrrole lipids) are seldomly isolated, and their presence is limited to certain marine organisms [8]. A series of 3-alkylpyrrole-2-carbaldehydes/carboxylic acid/methylcarboxylate was reported from the marine sponge

• a fermentation extract of Allostreptomyces sp. RD068384, a strain belonging to an almost unstudied actinomycetes genus within the family Streptomycetaceae. Compounds 1–5 are characterized by a pyrrole-2-carboxylic acid core decorated with a formyl group and an alkyl side chain. Secondary metabolites

Negishi-coupling-enabled synthesis of α-heteroaryl-α-amino acid building blocks for DNA-encoded chemical library applications

• Matteo Gasparetto,
• Balázs Fődi and
• Gellért Sipos

Beilstein J. Org. Chem. 2024, 20, 1922–1932, doi:10.3762/bjoc.20.168

• first attached to carboxylic acid functionalized DNA headpiece 7a (first reverse amidation). Next, the ester was hydrolyzed to obtain acid 9, and finally, a second reverse amidation with aniline afforded 10. Both the reverse amidation and the ester hydrolysis were performed following literature

Access to 2-oxoazetidine-3-carboxylic acid derivatives via thermal microwave-assisted Wolff rearrangement of 3-diazotetramic acids in the presence of nucleophiles

• Ivan Lyutin,
• Vasilisa Krivovicheva,
• Grigory Kantin and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2024, 20, 1894–1899, doi:10.3762/bjoc.20.164

• 191036, Russian Federation 10.3762/bjoc.20.164 Abstract In this work, we report an efficient approach to 2-oxoazetidine-3-carboxylic acid derivatives based on a thermally promoted Wolff rearrangement of diazotetramic acids in the presence of nucleophiles. The method allows easy variation of the

• well as a wide range of nucleophiles provides access to a structural diversity of medically relevant 2-oxoazetidine-3-carboxylic acid amides and esters. Keywords: β-lactams; diazotetramic acids; nucleophiles; spirocycles; thermolysis; Wolff rearrangement; Introduction The importance of the β-lactam

• ketenes 2 generated by a thermally promoted Wolff rearrangement [3]. The interaction of such ketenes with nucleophiles of different nature could serve as a source of libraries of structurally diverse 2-oxoazetidine-3-carboxylic acid derivatives 3 (Scheme 1). The 2-oxoazetidine-3-carboxylic acid

2-Heteroarylethylamines in medicinal chemistry: a review of 2-phenethylamine satellite chemical space

• Carlos Nieto,
• Alejandro Manchado,
• Ángel García-González,
• David Díez and
• Narciso M. Garrido

Beilstein J. Org. Chem. 2024, 20, 1880–1893, doi:10.3762/bjoc.20.163

• -ring bioisostere, but as carboxylic acid one, Schwarz et al. [79] developed tetrazole-based pregabalin bioisosteres 113–118 (Scheme 18). The target protein α2-δ is involved in neurotransmitters release reduction, as a model of anxiety and neuropathic pain. In general, submicromolar affinities were

The Groebke–Blackburn–Bienaymé reaction in its maturity: innovation and improvements since its 21st birthday (2019–2023)

• Cristina Martini,
• Muhammad Idham Darussalam Mardjan and
• Andrea Basso

Beilstein J. Org. Chem. 2024, 20, 1839–1879, doi:10.3762/bjoc.20.162

• -aminoimidazole scaffold prevented the GBB reaction to occur [52]. As it has already been described, DNA encoded GBB adducts can be effectively used in DEL screening techniques. Hwang et al. incorporated 2-amino-6-chloropyrimidine-4-carboxylic acid into a DNA sequence, reacted the resulting conjugate 51 through a

Ugi bisamides based on pyrrolyl-β-chlorovinylaldehyde and their unusual transformations

• Alexander V. Tsygankov,
• Vladyslav O. Vereshchak,
• Tetiana O. Savluk,
• Serhiy M. Desenko,
• Valeriia V. Ananieva,
• Oleksandr V. Buravov,
• Yana I. Sakhno,
• Svitlana V. Shishkina and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2024, 20, 1773–1784, doi:10.3762/bjoc.20.156

• which the Z-configuration of the chlorovinyl fragment was detected. Post-Ugi transformations As previously mentioned [32], the introduction of the convertible 2‑bromo-6-isocyanopyridine into the Ugi bisamide structure allows the conversion of the newly formed amide into a carboxylic acid fragment after

• acid hydrolysis. Similar results were obtained by Dömling and co-workers [27], who used 2-nitrobenzyl isocyanide as a universal convertible isocyanide, and the amide group was also converted into a carboxylic acid under the conditions of acid hydrolysis (Scheme 2). Therefore, taking into account the

Harnessing unprotected deactivated amines and arylglyoxals in the Ugi reaction for the synthesis of fused complex nitrogen heterocycles

• Javier Gómez-Ayuso,
• Pablo Pertejo,
• Tomás Hermosilla,
• Israel Carreira-Barral,
• Roberto Quesada and
• María García-Valverde

Beilstein J. Org. Chem. 2024, 20, 1758–1766, doi:10.3762/bjoc.20.154

• acid, indole-2-carboxylic acid, pyrrole-2-carboxylic acid or N-phenylglycine has allowed the use of these compounds in the Ugi reaction without triggering competitive reactions. The additional functional group present in the resulting Ugi adduct can be leveraged in different post-condensation

• choice [23]. Synthesis of piperazinones On the basis of these results, we planned to synthesise piperazinone derivatives following a similar strategy. Thus, we chose different deactivated 2-amino-substituted carboxylic acid derivatives such as the indole-2-carboxylic acid, recently used in a similar

• strategy with aromatic amines [24], pyrrole-2-carboxylic acid and N-phenylglycine, and carried out their reactions with arylglyoxals, alkylamines and isocyanides (Scheme 5). As we expected, the cyclization product 9 was observed, although the complete cyclization of the Ugi adduct, found as the enol

Syntheses and medicinal chemistry of spiro heterocyclic steroids

• Laura L. Romero-Hernández,
• Ana Isabel Ahuja-Casarín,
• Penélope Merino-Montiel,
• Sara Montiel-Smith,
• José Luis Vega-Báez and
• Jesús Sandoval-Ramírez

Beilstein J. Org. Chem. 2024, 20, 1713–1745, doi:10.3762/bjoc.20.152

• of 10% Pd/C and 5% Pd/CaCO3 yielded reduced compound 19. Cleavage of the THP group with Amberlist-15® resin and a final Jones oxidation of the primary alcohol to the carboxylic acid, led to cyclization with the 17β-OH group affording the lactone 20 in a moderate overall yield (Scheme 6). Biological

• of a set of azomethine ylides and the 16-arylidene steroids 48a,b. Ylides were generated in situ by the nitrogen attack of the thiazolidine ring from 1,3-thiazolidine-4-carboxylic acid to a carbonyl group of acenaphthenequinone. The resulting reaction produced an iminium group, which promoted the

• on normal human peripheral blood mononuclear cells (PBMC). In 2003, a direct transformation of tetraoxanes to amides via carboxylic acid was also reported by the same research group [68]. Some amides were synthesized using methyl glycinate, di-n-propylamine, and piperidine with significant

Chemo-enzymatic total synthesis: current approaches toward the integration of chemical and enzymatic transformations

• Ryo Tanifuji and
• Hiroki Oguri

Beilstein J. Org. Chem. 2024, 20, 1693–1712, doi:10.3762/bjoc.20.151

• condensation of 73 and 74, followed by highly-diastereoselective vinylogous Mukaiyama aldol reaction and subsequent protecting group manipulations [81][82][83]. The separately synthesized left and right segments, 72 and 75, were then assembled via Horner–Wadsworth–Emmons (HWE) olefination to give carboxylic

• acid 76 in a 4:1 diastereomeric ratio. Thioesterification and removal of the TBS group furnished the desired thioester 77 as a mimic of biosynthetic intermediate 64. With synthetic substrate 77 for enzymatic conversions in hand, Sherman and co-workers attempted to overexpress TylGIV and TylGV, however