Recent advances in the electrochemical synthesis of organophosphorus compounds

• Babak Kaboudin,
• Milad Behroozi,
• Sepideh Sadighi and
• Fatemeh Asgharzadeh

Beilstein J. Org. Chem. 2025, 21, 770–797, doi:10.3762/bjoc.21.61

• experiments, a radical process was proposed for this coupling reaction via an Mn(III)–P intermediate (Scheme 9). The method was also applied to scale up to gram-scale synthesis. In 2023, Wu et al. [54] also reported another heteroaromatic C–P coupling of benzothiazole with diarylphosphine oxides by an

Non-covalent organocatalyzed enantioselective cyclization reactions of α,β-unsaturated imines

• Sergio Torres-Oya and
• Mercedes Zurro

Beilstein J. Org. Chem. 2024, 20, 3221–3255, doi:10.3762/bjoc.20.268

• screening of reaction conditions, it was found that the best organocatalyst was also bifunctional squaramide IX, but in this case a lower catalyst loading could be used in the reaction (Scheme 13). Under the optimized reaction conditions, 27 different chiral directly linked benzothiazole-dihydroimidazoles

• organocatalysts functioning as Brønsted bases remain rarer. Among the different azadienes employed in the different asymmetric transformations, it is common to identify cyclic α,β-unsaturated imines such as aurone-derived azadienes, saccharin-derived azadienes and benzothiazole-derived imines which in combination

5th International Symposium on Synthesis and Catalysis (ISySyCat2023)

• Anthony J. Burke and
• Elisabete P. Carreiro

Beilstein J. Org. Chem. 2024, 20, 2704–2707, doi:10.3762/bjoc.20.227

• RdRp inhibitor, and their evaluation in an in vitro polymerase assay, targeting SARS-CoV-2 [17]. The synthesis of the new molecules involved three modifications of the HeE1-2Tyr inhibitor, which included changing the core structure from a benzothiazole to a benzoxazole unit and simplifying it to

Heterocycle-guided synthesis of m-hetarylanilines via three-component benzannulation

• Andrey R. Galeev,
• Maksim V. Dmitriev,
• Alexander S. Novikov and
• Andrey N. Maslivets

Beilstein J. Org. Chem. 2024, 20, 2208–2216, doi:10.3762/bjoc.20.188

• with aniline resulted in low conversion of 1b even at prolonged reaction times (up to 10 days). The addition of molecular sieves, excess aniline, or acid catalysts did not significantly affect the conversion (Scheme 3). 1,3-Diketones with benzothiazole (1c, σm/σp 0.338/0.390) and oxazole (1d, σm/σp

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

• addition and remained unreacted. Formation of 2h did not occur, however, we observed the formation of unidentified side products. Interestingly, the presence of a free carboxylic group is well tolerated (2f). Benzothiazole 1i proved to be an excellent substrate for this reaction, leading to the desired

• results, thiazole 2b, benzothiazole 2i and benzimidazole 2t react very well with sodium nitrite in an acidic environment (Scheme 6, red section). Among the various subclasses of compounds, pyrazole 2l exhibited a high reactivity using t-BuONO and EtONa in ethanol (Scheme 6, red section). On the other hand

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

• a variation of the GBB reaction employing benzothiazole acetonitrile 104 (X = S) in place of the amidine component (Scheme 33). Knoevenagel condensation with an aldehyde in the presence of 2-(hydroxymethyl)pyrrolidinium acetate produced conjugated imines 105 as the reaction intermediates. Once

Novel analogues of a nonnucleoside SARS-CoV-2 RdRp inhibitor as potential antivirotics

• Luca Julianna Tóth,
• Kateřina Krejčová,
• Milan Dejmek,
• Eva Žilecká,
• Blanka Klepetářová,
• Lenka Poštová Slavětínská,
• Evžen Bouřa and
• Radim Nencka

Beilstein J. Org. Chem. 2024, 20, 1029–1036, doi:10.3762/bjoc.20.91

• modifications of HeE1-2Tyr: conversion of the core from a benzothiazole to a benzoxazole moiety and two different scaffold simplifications, respectively. We provide a novel synthetic approach and, in addition, evaluate the final molecules in an in vitro polymerase assay for biological activity. Keywords

Perspectives on push–pull chromophores derived from click-type [2 + 2] cycloaddition–retroelectrocyclization reactions of electron-rich alkynes and electron-deficient alkenes

• Michio Yamada

Beilstein J. Org. Chem. 2024, 20, 125–154, doi:10.3762/bjoc.20.13

Application of N-heterocyclic carbene–Cu(I) complexes as catalysts in organic synthesis: a review

• Nosheen Beig,
• Varsha Goyal and
• Raj K. Bansal

Beilstein J. Org. Chem. 2023, 19, 1408–1442, doi:10.3762/bjoc.19.102

• effective. This method afforded the products with high selectivity and it could be extended to a variety of substrates, such as benzoxazole, benzothiazole, oxazole, and even acidic hydrocarbons and aniline. Fukuzama and co-workers [91] accomplished the C–H carboxylation of benzoxazole and benzothiazole

Non-noble metal-catalyzed cross-dehydrogenation coupling (CDC) involving ether α-C(sp³)–H to construct C–C bonds

• Hui Yu and
• Feng Xu

Beilstein J. Org. Chem. 2023, 19, 1259–1288, doi:10.3762/bjoc.19.94

• benzothiazole, in which benzothiazole compounds have higher reactivity and regioselectivity than thiazole. In 2014, Lei et al. successfully realized the copper-catalyzed oxidative alkenylation of simple ethers to construct allyl ethers in the presence of di-tert-butyl peroxide and KI (Scheme 10) [60]. The

Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

Nucleophile-induced ring contraction in pyrrolo[2,1-c][1,4]benzothiazines: access to pyrrolo[2,1-b][1,3]benzothiazoles

• Ekaterina A. Lystsova,
• Maksim V. Dmitriev,
• Andrey N. Maslivets and
• Ekaterina E. Khramtsova

Beilstein J. Org. Chem. 2023, 19, 646–657, doi:10.3762/bjoc.19.46

• targeted cancer therapy development. Keywords: 1,4-benzothiazine; 1,3-benzothiazole; 1H-pyrrole-2,3-diones; nitrogen heterocycle; sulfur heterocycle; Introduction Pyrrolo[2,1-b][1,3]benzothiazole (PBTA) is an angularly fused sulfur and nitrogen-containing heterocyclic scaffold. Its derivatives are

• ] and reactions of 3-acyl-2,3-dihydro-1,3-benzothiazole-2-carbonitriles with acetylenedicarboxylate (Scheme 1, entry 9) [4]. The second group of approaches to the PBTA scaffold is an annulation of o-aminothiophenol with a pyrrolothiazole moiety (Scheme 2). It includes catalytic cascade reactions of o

• 1 (Scheme 5). Firstly, FPDs 1 bear a 1,4-benzothiazine moiety that is known to be prone to undergo a ring contraction reaction to afford the corresponding 1,3-benzothiazole derivatives under the action of nucleophiles [39][40][41][42], oxidizing agents [43][44][45][46][47][48] or ultraviolet

Development of N-F fluorinating agents and their fluorinations: Historical perspective

• Teruo Umemoto,
• Yuhao Yang and
• Gerald B. Hammond

Beilstein J. Org. Chem. 2021, 17, 1752–1813, doi:10.3762/bjoc.17.123

• -alkylarenesulfonamides, N-fluoropyridinium salts and derivatives, N-fluoroquinuclidium salts, N-fluoro-trifluoromethanesulfonimide, N-fluoro-sultams, N-fluoro-benzothiazole dioxides, N-fluoro-lactams, N-fluoro-o-benzenedisulfonimide, N-fluoro-benzenesulfonimide, 1-alkyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane salts, N

• fluorinating agents for an enantioselective fluorination was demonstrated (Scheme 22). 1-10. N-Fluoro-3,3-dimethylbenzothiazole dioxide In 1989, Lang and co-worker developed the saccharin-derived N-fluorosultam N-fluoro-3,3-dimethyl-2,3-dihydro-1,2-benzothiazole-1,1-dioxide (10-2) from the known precursor 10-1

Chemical approaches to discover the full potential of peptide nucleic acids in biomedical applications

• Nikita Brodyagin,
• Martins Katkevics,
• Venubabu Kotikam,
• Christopher A. Ryan and
• Eriks Rozners

Beilstein J. Org. Chem. 2021, 17, 1641–1688, doi:10.3762/bjoc.17.116

Double-headed nucleosides: Synthesis and applications

• Vineet Verma,
• Jyotirmoy Maity,
• Vipin K. Maikhuri,
• Ritika Sharma,
• Himal K. Ganguly and
• Ashok K. Prasad

Beilstein J. Org. Chem. 2021, 17, 1392–1439, doi:10.3762/bjoc.17.98

• /hydroxy)phenyl [26], 3/4-(N-((dimethylamino)methylidene)aminosulfonyl)phenyl [26][27], and sulfonamido-substituted benzothiazole [28] attached as an additional head are also reported in this review article. Literature data revealed that most of the double-headed nucleosides have the first nucleobase

Synthetic accesses to biguanide compounds

• Oleksandr Grytsai,
• Cyril Ronco and
• Rachid Benhida

Beilstein J. Org. Chem. 2021, 17, 1001–1040, doi:10.3762/bjoc.17.82

• later to form differently substituted 2-guanidinobenzimidazoles and 2-guanidinobenzothiazoles, respectively, with good to excellent yields (Scheme 11A) [30][31]. The efficiency of the reaction process usually follows the order: benzothiazole > benzimidazole > benzoxazole. The lower yields obtained with

• benzothiazole and benzimidazole-based sulfonylguanidine compounds were derived by the sulfonylation of the corresponding 2-guanidinobenzazoles and assayed as potential antimelanoma agents (Scheme 11C) [33]. Of note, a dearomatization of the benzothiazole ring was observed while grafting a sulfoguanidinyl group

Synthetic reactions driven by electron-donor–acceptor (EDA) complexes

• Zhonglie Yang,
• Yutong Liu,
• Kun Cao,
• Xiaobin Zhang,
• Hezhong Jiang and
• Jiahong Li

Beilstein J. Org. Chem. 2021, 17, 771–799, doi:10.3762/bjoc.17.67

• derivative 38 initiated by an EDA complex. Synthesis of spiropyrroline derivative 40 initiated by an EDA complex. Synthesis of benzothiazole derivative 43 initiated by an EDA complex. Synthesis of perfluoroalkyl-s-triazine derivative 45 initiated by an EDA complex. Synthesis of indoline derivative 47

Identification of volatiles from six marine Celeribacter strains

• Anuj Kumar Chhalodia,
• Jan Rinkel,
• Dorota Konvalinkova,
• Jörn Petersen and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2021, 17, 420–430, doi:10.3762/bjoc.17.38

• compounds ethyl (E)-3-(methylsulfanyl)acrylate and 2-(methyldisulfanyl)benzothiazole were identified and their structures were verified by synthesis. Feeding experiments with [methyl-2H3]methionine, [methyl-13C]methionine and [34S]-3-(dimethylsulfonio)propanoate (DMSP) resulted in the high incorporation

• into dimethyl trisulfide and S-methyl methanethiosulfonate, and revealed the origin of the methylsulfanyl group of 2-(methyldisulfanyl)benzothiazole from methionine or DMSP, while the biosynthetic origin of the benzothiazol-2-ylsulfanyl portion could not be traced. The heterocyclic moiety of this

• menaquinones [58]. Sulfur-containing compounds included dimethyl trisulfide (37), released by all six species, S-methyl methanethiosulfonate (38), 2-acetylthiazole (39), and benzothiazole (40), the latter also in the extracts from all six strains. In addition, the extracts from the three species C. marinus, C

CF₃-substituted carbocations: underexploited intermediates with great potential in modern synthetic chemistry

• Anthony J. Fernandes,
• Armen Panossian,
• Bastien Michelet,
• Agnès Martin-Mingot,
• Frédéric R. Leroux and
• Sébastien Thibaudeau

Beilstein J. Org. Chem. 2021, 17, 343–378, doi:10.3762/bjoc.17.32

• , affording biaryl species 161. Using this strategy, several trifluoromethyl ketones 162 and alcohols 163 bearing heteroaryl substituents (i.e., benzothiazole, quinoline, isoquinoline, benzimidazole, or imidazole) prone to be protonated were elegantly converted into the corresponding alcohols 163 and biphenyl

Recent developments in enantioselective photocatalysis

• Callum Prentice,
• James Morrisson,
• Andrew D. Smith and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2020, 16, 2363–2441, doi:10.3762/bjoc.16.197

• -established benzoxazole and benzothiazole ligands. Such complexes have then been used for α-functionalisations [117], RCAs [118], and cycloaddition reactions [119]. As much of Meggers work has been summarised previously [120], here we will include only recent examples from each reaction class. If an

Synthesis of 1,4-benzothiazinones from acylpyruvic acids or furan-2,3-diones and o-aminothiophenol

• Ekaterina E. Stepanova,
• Maksim V. Dmitriev and
• Andrey N. Maslivets

Beilstein J. Org. Chem. 2020, 16, 2322–2331, doi:10.3762/bjoc.16.193

• the catalyst SiO2@H3PW12O40 [21], the reaction of tetracarbonyl compounds with o-aminothiophenol (1a) [22][23], the reaction of copper(II) chelate of ethyl pentafluorobenzoylpyruvate with o-aminothiophenol (1a, one example) [24] and the reaction of DMAD with 6-nitro-1,3-benzothiazole (one example) [25

When metal-catalyzed C–H functionalization meets visible-light photocatalysis

• Lucas Guillemard and
• Joanna Wencel-Delord

Beilstein J. Org. Chem. 2020, 16, 1754–1804, doi:10.3762/bjoc.16.147

Aldehydes as powerful initiators for photochemical transformations

• Maria A. Theodoropoulou,
• Nikolaos F. Nikitas and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2020, 16, 833–857, doi:10.3762/bjoc.16.76

• ., formamide) and ethers through C–H activation using various five- and six-membered heteroarenes (e.g., benzothiazole) and employing benzaldehyde (8) as the photoinitiator [56]. This protocol was compatible with both C(sp3)–H activation (N-alkyl C–H bonds of amides or Cα–H bonds of ethers) and C(sp2)–H

• activation (carbonyl C–H bonds of formamides). Some of the amides or ethers found to be compatible with this method are shown in Scheme 26. A wide range of heteroarenes 114 was also found compatible with this method, including substituted benzothiazole substrates, substituted benzimidazoles, and thiazoles

• (Scheme 27b). The sulfate radical then reacted with formamide (106) to produce the carbamoyl radical 125, which could perform a nucleophilic addition to the C-2 position of the protonated benzothiazole 126. A deprotonation, followed by an oxidation, most probably by the intermediates 121 and 122, could

A systematic review on silica-, carbon-, and magnetic materials-supported copper species as efficient heterogeneous nanocatalysts in “click” reactions

• Pezhman Shiri and
• Jasem Aboonajmi

Beilstein J. Org. Chem. 2020, 16, 551–586, doi:10.3762/bjoc.16.52

• , compound 36 could be recycled and used in seven subsequent cycles. A further example of a silica-supported CuAAC catalyst was reported by Moghadam et al. (Scheme 7) [29]. In this study, the bis(benzothiazole)-substituted pyridine ligand BTP (41) was synthesized through the condensation of 2-aminothiophenol

• . Subsequently, a range of hybrid molecules, including triazole–benzimidazoles 50–53, triazole–benzothiazole 54, and triazole–benzoxazole 55, was prepared under the above-mentioned conditions (Scheme 8). The benefits of this catalytic system were mild reaction conditions, low catalyst loadings, a diverse set of

Recent developments in photoredox-catalyzed remote ortho and para C–H bond functionalizations

• Rafia Siddiqui and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 248–280, doi:10.3762/bjoc.16.26

• substituents (Scheme 5), and (v) the rate-determining step (i.e., breaking of the C–H bond) was suggested to follow a first-order kinetic isotope effect (KH/KD = 5). As such, a library of benzothiazole derivatives was reported using this methodology, and a plausible mechanism is shown in Figure 9. Synthesis of