Metal‐Free Thiolation of Imidazopyridines with Functionalized Haloalkanes Using Elemental Sulfur

Abstract

Thea ssembly of two functional molecules via asulfurlinking atom allowsanaccess to adiverse array of thioether-containing compounds.H erein, we disclose am etal-free thiolation of imidazopyridines with av ariety of functionalized haloalkanes using elemental sulfur.

New synthesis of 2-aroylbenzothiazoles via metal-free domino transformations of anilines, acetophenones, and elemental sulfur

“…Reactions with either simple aliphatic ketones or other heterocycles such as 2acetylfuran were not successful. In a second series of experiments, many anilines were employed for the synthesis of 2aroylbenzothiazoles via iodine-promoted three-component reaction (entries [13][14][15][16][17][18][19][20][21]. Under these reaction conditions, 2-aroylbenzothiazoles containing different substituents were synthesized and isolated in reasonable yields for the case of para-toluidine (3ba, 3bb, 3bc, 3bg, and 3bk, entries 13-17).…”

“…[17][18][19] Elemental sulfur has been considered as a green sulfur source for the synthesis of sulfurcontaining organic compounds as it is nontoxic, abundant, stable, and easy handling. [20][21][22] Possessing several oxidation states, extending from À2 to +6, it could be used as either an oxidant or a reductant for numerous organic reactions. 23 Furthermore, elemental sulfur-catalyzed/mediated synthetic strategies have been studied.…”

Efficient Synthesis of Diverse 5-Thio- or 5-Selenotriazoles: One-Pot Multicomponent Reaction from Elemental Sulfur or Selenium

“…However, a reaction that gives 5-thiotriazoles in one-pot starting from sulfur powder remains elusive. 20 The key issue is that a sulfur atom cannot direct intercept the copper(I) triazolide intermediate. Thus, under multicomponent reaction conditions, the challenges are: 1. in situ transforming S 8 into a sulfenylating agent that has appropriate reactivity toward copper(I) triazolides, instead of copper acetylides; 2. efficient generation of copper(I) triazolides in situ and without interruption; and 3. the reaction taking place without forming symmetric sulfides and disulfides caused by halides and triazoles.…”

Transition Metal‐Free Sulfenylation of C−H Bonds for C−S Bond Formation in Recent Years: Mechanistic Approach and Promising Future

“…The intermediate 194 B attacks on alkylbromide ( 219 ) in presence of base to yield another intermediate 220 A which eventually isomerize to desired product ( 220 ) (Scheme 72). [183] …”

“…Finally, it was proposed that a nucleophilic attack of imidazopyridine's resonance hybrid ( 13 A 220) (Scheme 72). [183] S-methylthiourea (SMT) has been widely used for the functionalisation of heterocycles, [184] but only few reports focus it as thiomethyl source. [185] Extending the scope and application of S-alkylthiourea in sulfenylation chemistry, Zhang and coworkers [186] have utilized S-alkylisothiourea sulfate salt as an alkylthiol source under basic condition.…”