O,S,Se-containing Biginelli products based on cyclic β-ketosulfone and their postfunctionalization

• Kateryna V. Dil and
• Vitalii A. Palchykov

Beilstein J. Org. Chem. 2024, 20, 2143–2151, doi:10.3762/bjoc.20.184

• of condensed thiazoles and tetrazoles. In silico assessment of ADMET parameters shows that most compounds meet the lead-likeness requirements. The biological profiles of new compounds demonstrate high probability levels of activity against the following pathogens/diseases: Candida albicans, Alphis

• the postmodification of the Biginelli products [2]. Both approaches were tested in this work. We used Hantzsch-type thiazole synthesis for postmodification of product 2a. By employing 2-bromoacetophenone, bromomalononitrile and 2-bromo-1-tetralone we obtained condensed thiazoles 3–5 in 67–88% yields

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

• Supporting Information File 1). We decided to explore the potential of this methodology for the formation of α-heteroarylacetates. In particular, we were curious to see whether this methodology translates well for five-membered heteroarene substrates (e.g., thiazoles, pyrazoles, imidazoles) which are usually

• Negishi reaction (Supporting Information File 1). Preliminary experiments were carried out with and without blue light irradiation in the PhotoCubeTM photoreactor [45]. These experiments revealed that while the conversion of imidazoles and pyrazoles benefits from irradiation, thiazoles seem to be largely

• conditions in hand, we proceeded with the investigation of the heteroaryl halide scope in batch (Scheme 3). Thiazoles proved to be challenging substrates typically affording the desired products in moderate yields (2b–h). While 2-chlorothiazole led to the production of 2b in 44% yield, 2-bromo-5

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

• studies. Thiazoles: 2-Thiazolylethylamine was characterized as a more selective and potent histamine H1 agonist [70]. Based on this, Govoni et al. [71] analyzed the pharmacological profile of several histamine H1 antagonists, with a section covering thiazole-based compounds. 2-(Thiazol-4-yl)ethylamine (99

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

• , such as a one-pot four-component synthesis and the use of ionic liquids as solvents [30]. Kanchithalaivan et al. [31] reported a library of 16-spiro pyrrolo[1,2-c][1,3]thiazoles of trans-androsterone and DHEA (49a and 49b, respectively). The syntheses were achieved through the 1,3-dipolar cycloaddition

Methyltransferases from RiPP pathways: shaping the landscape of natural product chemistry

• Maria-Paula Schröder,
• Isabel P.-M. Pfeiffer and
• Silja Mordhorst

Beilstein J. Org. Chem. 2024, 20, 1652–1670, doi:10.3762/bjoc.20.147

• encoded in the pbt cluster of P. rosea. The thiopeptide GE2270 encoded by pbt undergoes further regioselective modification through C-methylation of thiazoles. The two rSAM MTs PbtM2 and PbtM3 methylate thiazole E and thiazole D, respectively [64]. PbtM2 and PbtM3 show substantial sequence similarities to

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

• adjacent C=C bond, various conjugated alkenyl C–H bonds can also be activated to construct functionalized ethers. In 2013, Wang et al. achieved a mild Cu(OTf)2-catalyzed CDC of (benzo)thiazoles with cyclic ethers in the presence of K2S2O8 (Scheme 9) [59]. The catalytic system is also suitable for

Enabling artificial photosynthesis systems with molecular recycling: A review of photo- and electrochemical methods for regenerating organic sacrificial electron donors

• Grace A. Lowe

Beilstein J. Org. Chem. 2023, 19, 1198–1215, doi:10.3762/bjoc.19.88

Eschenmoser coupling reactions starting from primary thioamides. When do they work and when not?

• Lukáš Marek,
• Jiří Váňa,
• Jan Svoboda and
• Jiří Hanusek

Beilstein J. Org. Chem. 2023, 19, 808–819, doi:10.3762/bjoc.19.61

• ) without any external thiophile [1][2][5][6]. However, the acidifying effect of the Z-group appears to be not the only prerequisite for successful ECR because in most cases 2-halomalonates [16][17][18][19] and 2-chloroacetoacetates [20] give the corresponding thiazoles and thiazolones, respectively (yields

• ammonium salts [22]. All experiments with salts 6a,b derived from 2b and thiobenzamide or thioacetamide showed that three of four possible products (thiazoles 8a,b, ECR products 9a,b and nitriles; cf. Scheme 3) are formed depending on the reaction conditions specified in Table 1 and Supporting Information

• give the zwitterionic intermediates 6a,b'' necessary for successful ECR. On the other hand, without any base only thiazoles 7a,b are formed probably from isomeric forms 6a,b' of the starting salts 6a,b. In contrast to the tricyclic intermediate 16 formed from oxindole α-thioiminium salt (15), which in

A one-pot electrochemical synthesis of 2-aminothiazoles from active methylene ketones and thioureas mediated by NH₄I

• Shang-Feng Yang,
• Pei Li,
• Zi-Lin Fang,
• Sen Liang,
• Hong-Yu Tian,
• Bao-Guo Sun,
• Kun Xu and
• Cheng-Chu Zeng

Beilstein J. Org. Chem. 2022, 18, 1249–1255, doi:10.3762/bjoc.18.130

• , the in situ generated α-iodoketone was proposed to be the key active species. Keywords: 2-aminothiazoles; electrosynthesis; indirect electrolysis; halide ion; Introduction Thiazoles are prevalent structural motifs in a wide range of natural products [1] and synthetic molecules possessing various

• ], dyes [13], etc. These important features of thiazoles have driven intense interests in their facile synthesis [14][15][16][17]. Among various synthetic routes to the thiazole unit, the Hantzsch condensation of α-halo ketones (dielectrophiles) with various thioureas (dinucleophiles) should be the most

• well-known method (Scheme 1a) [18]. Since active methylene ketones are able to be in situ α-halogenated, the modified Hantzsch condensation of active methylene ketones with thioureas has attracted increasing attention in thiazoles’ synthesis, thereby saving costs and time needed to prepare the required

Microwave-assisted multicomponent reactions in heterocyclic chemistry and mechanistic aspects

• Shivani Gulati,
• Stephy Elza John and
• Nagula Shankaraiah

Beilstein J. Org. Chem. 2021, 17, 819–865, doi:10.3762/bjoc.17.71

Synthesis of (Z)-3-[amino(phenyl)methylidene]-1,3-dihydro-2H-indol-2-ones using an Eschenmoser coupling reaction

• Lukáš Marek,
• Lukáš Kolman,
• Jiří Váňa,
• Jan Svoboda and
• Jiří Hanusek

Beilstein J. Org. Chem. 2021, 17, 527–539, doi:10.3762/bjoc.17.47

• we recently discovered [32][33] a new synthetic pathway involving a rearrangement of 2-aryl-5-(2-aminophenyl)-4-hydroxy-1,3-thiazoles (e.g., 8aa–ad in Scheme 2) leading to the 3-[amino(aryl)methylidene]-1,3-dihydro-2H-indol-2-ones containing an unsubstituted amino group and the oxindole nucleus. In

• the present paper, we want to describe an optimized procedure avoiding the intermediary thiazoles and to demonstrate the usefulness and wide group tolerability of our new synthetic approach for the preparation of a library of substituted phenyl and amino derivatives (Table 1). A number of the

• ) through the intermediary (and in most cases isolable) 2-aryl-5-(2-aminophenyl)-4-hydroxy-1,3-thiazoles 8aa–ad formed from 3-bromooxindole (1a) and various substituted primary aromatic thioamides (e.g., thiobenzamides 2a–d) in acetonitrile (Scheme 2). Although the overall yields of such a two-step

Regioselective synthesis of heterocyclic N-sulfonyl amidines from heteroaromatic thioamides and sulfonyl azides

• Vladimir Ilkin,
• Vera Berseneva,
• Tetyana Beryozkina,
• Tatiana Glukhareva,
• Lidia Dianova,
• Wim Dehaen,
• Eugenia Seliverstova and
• Vasiliy Bakulev

Beilstein J. Org. Chem. 2020, 16, 2937–2947, doi:10.3762/bjoc.16.243

• -arylamino-1,2,3-triazole-4-N-sulfonylcarbimidamides. 2,5-Dithiocarbamoylpyridine reacts with sulfonyl azides to form a pyridine bearing two sulfonyl amidine groups. Keywords: amidines; Dimroth rearrangement; isoxazoles; sulfonyl thiazoles; thioamides; 1,2,3-triazoles; Introduction The biological activity

Access to highly substituted oxazoles by the reaction of α-azidochalcone with potassium thiocyanate

• Mysore Bhyrappa Harisha,
• Pandi Dhanalakshmi,
• Rajendran Suresh,
• Raju Ranjith Kumar and
• Shanmugam Muthusubramanian

Beilstein J. Org. Chem. 2020, 16, 2108–2118, doi:10.3762/bjoc.16.178

• -azidochalcones as the precursor [9], we herein report the preparation of highly substituted oxazoles and thiazoles. Oxazoles are ubiquitously found in various natural products [10][11][12][13][14], pharmaceuticals [15][16][17][18], functional materials [19][20] as well as in several organic building blocks [21

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

• allowed a significant improvement of the reaction efficiency. The C–H coupling was compatible with a large panel of heteroaromatic substrates including benzoxazoles, oxazoles, thiazoles, and oxadiazoles, as well as non-aromatic oxazolines. Although the initial protocol necessitated the use of a

Synthesis of new fluorescent molecules having an aggregation-induced emission property derived from 4-fluoroisoxazoles

• Kazuyuki Sato,
• Akira Kawasaki,
• Yukiko Karuo,
• Atsushi Tarui,
• Kentaro Kawai and
• Masaaki Omote

Beilstein J. Org. Chem. 2020, 16, 1411–1417, doi:10.3762/bjoc.16.117

• heteroaromatic systems, especially those comprising two heteroatoms such as pyrazoles [28][29], isoxazoles [30], and thiazoles [31][32]. Recently, we reported the selective fluorination of isoxazoles, to give monofluorinated isoxazoles 3 or trifluorinated isoxazolines 4 in moderate to good yields (Scheme 1) [33

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

• 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

The reaction of arylmethyl isocyanides and arylmethylamines with xanthate esters: a facile and unexpected synthesis of carbamothioates

• Narasimhamurthy Rajeev,
• Toreshettahally R. Swaroop,
• Ahmad I. Alrawashdeh,
• Shofiur Rahman,
• Abdullah Alodhayb,
• Seegehalli M. Anil,
• Kuppalli R. Kiran,
• Chandra,
• Paris E. Georghiou,
• Kanchugarakoppal S. Rangappa and
• Maralinganadoddi P. Sadashiva

Beilstein J. Org. Chem. 2020, 16, 159–167, doi:10.3762/bjoc.16.18

• reported the synthesis of thiazoles from xanthate esters [31]. In continuation of this ongoing work, we planned to synthesize 5-alkoxy-4-arylthiazoles 3 by the sodium hydride/DMF-mediated reaction of arylmethyl isocyanides 2 with S-alkyl xanthate esters 1 or O-aryl/O-alkyl dithiocarbonates. Unexpectedly

Reactions of 2-carbonyl- and 2-hydroxy(or methoxy)alkyl-substituted benzimidazoles with arenes in the superacid CF₃SO₃H. NMR and DFT studies of dicationic electrophilic species

• Dmitry S. Ryabukhin,
• Alexey N. Turdakov,
• Natalia S. Soldatova,
• Mikhail O. Kompanets,
• Alexander Yu. Ivanov,
• Irina A. Boyarskaya and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2019, 15, 1962–1973, doi:10.3762/bjoc.15.191

• reaction [14]. Recently, several hydroxyalkylation reactions followed by alkylation of arenes have been reported involving heterocycle-based superelectrophiles: pyridines, thiazoles, quinolines, isoquinolines, pyrazines, pyrazoles, imidazole and furans, bearing a formyl (carbonyl) group [15][16][17][18][19

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

• Gagandeep Kour Reen,
• Ashok Kumar and
• Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

• derivatives have been reported by the group of R. K. Reddy [113]. The protocol offered an open air, ligand- and base-free methodology with an extension towards the synthesis of imidazo[1,2-a]pyrazines/pyrimidines and benzo[d]imidazo[2,1-b]thiazoles. For this reaction, they have synthesized the respective

Synthesis of (macro)heterocycles by consecutive/repetitive isocyanide-based multicomponent reactions

• Angélica de Fátima S. Barreto and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2019, 15, 906–930, doi:10.3762/bjoc.15.88

• products has been reviewed [15][16] and this review will focus only on IMCRs. Consecutive IMCRs Synthesis of small-ring heterocycles (tetrazoles, ketopiperazines, imidazoles, imidazolines and thiazoles) The use of consecutive Ugi reactions in the synthesis of heterocycles was first described in 2001 by Ugi

Oxidative and reductive cyclization in stiff dithienylethenes

• Michael Kleinwächter,
• Ellen Teichmann,
• Lutz Grubert,
• Martin Herder and
• Stefan Hecht

Beilstein J. Org. Chem. 2018, 14, 2812–2821, doi:10.3762/bjoc.14.259

• case of modified thiazoles [5] or using the strongly donating -PhNMe2 substituent [40]. In these compounds, the first oxidation wave is fully reversible and anodic cyclization occurs only after the second step, forming the open dication (EEC mechanism). By combining strongly electron-donating and

Applications of organocatalysed visible-light photoredox reactions for medicinal chemistry

• Michael K. Bogdos,
• Emmanuel Pinard and
• John A. Murphy

Beilstein J. Org. Chem. 2018, 14, 2035–2064, doi:10.3762/bjoc.14.179

• potential to be of interest if explored further. The good physical chemical properties of thiazoles, as well as their ability to act as isosteres to thiophenes, carbonyls and pyrazoles [49][50] make this scaffold an intriguing novel motif. 2.3 C(sp2)–X bond formation The obvious extension after considering

• thiocyanate functional group, which is a precursor group to many sulfur-containing functional groups, as well as heterocycles such as thiazoles and isothiazoles. The imidazo[1,2-a]pyridine core is a particularly interesting drug-like structure, e.g., electron poor, polar, of low basicity, etc. The scope of

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

• significant antibacterial activity against Gram-positive bacterial strains [50]. Several other distamycin analogs were synthesized by replacing one or more pyrrole rings with other heterocycles such as pyrazoles [51], benzofurans [52], thiazoles, thiophenes, imidazole and oxazoles [53] in order to establish a

• reported other conjugates with two thiazoles directly linked via an amide bond, which retained activity to a lesser extent. Baraldi et al. designed and synthesized a novel conjugate 7 by combining naturally occurring antitumor agent distamycin A with the pyrrolo[2,1-c][1,4]benzodiazepine moiety (PBD

Progress in copper-catalyzed trifluoromethylation

• Guan-bao Li,
• Chao Zhang,
• Chun Song and
• Yu-dao Ma

Beilstein J. Org. Chem. 2018, 14, 155–181, doi:10.3762/bjoc.14.11

• ]thiazoles and imidazopyridines, were compatible with this reaction conditions affording the corresponding analogues in moderate to good yields. The proposed reaction mechanism is shown in Scheme 38. Initially, the trifluoromethyl radical is generated in situ by the reaction of TBHP with CF3SO2Na in the

Photocatalytic formation of carbon–sulfur bonds

• Alexander Wimmer and
• Burkhard König

Beilstein J. Org. Chem. 2018, 14, 54–83, doi:10.3762/bjoc.14.4

• form an aryl radical. This reactive intermediate reacts with the anion of the respective thiol to form the corresponding diaryl sulfide adducts. The reaction conditions tolerate functional groups like alcohols, esters, halides, the trifluoromethyl group and heterocyclic substrates like thiazoles or