Thiol substrate-promoted dehydrogenative cyclization of arylmethyl thiols with ortho-substituted amines: a universal approach to heteroaromatic compounds

Abstract

A thiol substrate-promoted one-pot synthesis of a library of heteroaromatic compounds was developed.

A green approach for the synthesis of 2-substituted benzoxazoles and benzothiazoles via coupling/cyclization reactions

“…GC-MS (EI, 70 eV) m/z: 51, 63, 77, 90, 102, 112, 127, 140, 153 182, 194, 210, 225. 2-(4-Chlorophenyl)benzoxazole (3d) (Sirgamalla et al, 2020;Tang et al, 2020;Yang, 2020;Zhou et al, 2020) White solid, mp ¼ 146-147 C 50, 63, 75, 92, 100, 111, 137, 166, 194, 201, 209, 229. 2-Phenylbenzothiazole (3e) (Choi et al, 2020;Zhang et al, 2019) White solid, mp ¼ 124-125 C 1 H NMR (500 MHz, CDCl 3 ): δ ¼ 8.12-8.08 (m, 3H), 7.91 (d, J ¼ 8.0 Hz, 1H), 7. 51-7.48 (m, 4H), 7.40-7.37 (m, 1H).…”

“…GC-MS (EI, 70 eV) m/z: 51, 58, 69, 82, 92, 108, 121, 139, 152, 167, 184, 196, 211. 2-(4-Methoxyphenyl)benzothiazole (3f) (Choi et al, 2020;Zhang et al, 2019) White solid, mp ¼ 123-124 C 1 H NMR (500 MHz, CDCl 3 ): δ ¼ 8. 3H),7.88 (d,J ¼ 8.0 Hz,1H),1H),1H), 7.00 (dt, J ¼ 3.0 Hz, 9.0 Hz, 2H), 3.89 (s, 3H).…”

Green and Practical Synthesis of Thioenamines and Chromones via Iodine-Catalyzed Cross-Dehydrogenation Coupling Reaction

“…Although various protocols for the synthesis of thioenamines have been developed, tandem or one-pot strategies, which avoid the preparation of starting materials and require the tedious isolation of intermediate products, − especially the strategies under simple reaction conditions, are still not explored sufficiently. Inspired by molecular iodine-mediated cross-dehydrogenation coupling reaction, as well as our long-term interest in organosulfur chemistry to construct various C–S bonds, we would like to report an iodine-catalyzed tandem synthesis of thioenamines.…”

One-Pot Synthesis of Benzoazole-Substituted Thioenamines via a Cross Dehydrogenation Coupling (CDC) Reaction

“…In recent years, various green and efficient synthetic methods such as continuous flow reactions, photocatalysis, electrocatalysis, biocatalysis, and one-pot synthesis have attracted more and more attention. In particular, a tandem or the one-pot synthetic strategy under simple conditions has attracted great attention from the organic chemistry community because it avoids the cumbersome and wasteful prefunctionalization of raw materials and does not require the separation of intermediates, affording the good chance to increase the yields of the final products. − On the other hand, due to the important role of organosulfur molecules in synthesis, pharmacy, and materials science, the construction of C–S bonds is the cornerstone of the synthesis of such compounds and is appreciated by organic chemists. − In addition, enamines are important organic intermediates that can participate in various basic synthetic applications, such as alkylation, amidation, conjugate addition, and cycloaddition reactions . Particular attention has been paid to compounds containing thioenamines moieties, as they often exhibit obvious biological properties (Figure ).…”