Diethylamine-Catalyzed Dimerization of Thiols: An Inexpensive and Green Method for the Synthesis of Homodisulfides Under Aqueous Conditions

Biodegradation tests of mercaptocarboxylic acids, their esters, related divalent sulfur compounds and mercaptans

“…Oxidative cyclisation of linear dimercaptans to cyclic disulfides was seen earlier under similar conditions (Houk and Whitesides 1987 ; Adamczyk et al 2015 ). Formation of disulfides via oxidation of SH groups can be achieved using a wide variety of oxidants, among them molecular oxygen (Ozen and Aydin 2006 ; Carril et al 2007 ; García Ruano et al 2008 ; Abaee et al 2011 ; Dewan et al 2012 ; Shard et al 2014 ), preferably under slightly alkaline conditions, in what is presumably a dimerisation of thiyl radicals formed by oxidation of thiolate anions (RSH → RS − → RS·,2 RS· → RSSR). The transformation mercaptan → disulfide consumes an amount of oxygen (4 RSH + O 2 → 2 RSSR + 2 H 2 O) that is small in most cases, e.g.…”

Thiol as a Synthon for Preparing Thiocarbonyl: Aerobic Oxidation of Thiols for the Synthesis of Thioamides

“…While our research group was investigating the oxidative transformation of alcohols and aldehydes, we found that the direct conversion of thiols to thiocarbonyl derivatives had never been reported previously . Although a few articles proposed the formation of a thiocarbonyl intermediate in the reaction of disulfides, the direct formation of thiocarbonyl compounds from thiols has never been reported under aerobic conditions . In this communication, we are pleased to report the use of thiols as a thiocarbonyl precursor for the synthesis of thioamides under aerobic conditions (Scheme ).…”

“…On the basis of Ogata’s publication of benzaldehyde formation from dibenzyl disulfide, we speculated that dibenzyl disulfide might be a key intermediate . Under these oxidative conditions, the formation of a disulfide intermediate is not surprising . The subsequent reaction of dibenzyl disulfide ( 1a′ ) with morpholine ( 1b ) was conducted in the absence of metal complexes and in the presence of CuCl 2 (2 mol %).…”

“…On the basis of the results in Tables and , we propose a plausible mechanism (Scheme ). In the beginning, 1a undergoes dimerization to form 1a′ under aerobic conditions . The deprotonation of disulfide 1a′ affords thiobenzaldehyde I , which reacts with morpholine to form II .…”

Aqueous DABCO, an efficient medium for rapid organocatalyzed Knoevenagel condensation and the Gewald reaction

“…In the framework of our studies on the chemistry of thiopyran-one structure 16 and its heterocyclic analogues, 17 and in continuation of our previous investigation on the development of aqueous mediated procedures, 18,19 we report herein the successful application of a H 2 O/1,4-diazabicyclo[2.2.2]octane (DABCO) * Correspondence: abaee@ccerci.ac.ir medium, which can cause rapid condensation of ketones 1 with malononitrile derivatives 2 to produce the Knoevenagel products 3 within a few minutes (3)(4)(5)(6)(7)(8)(9)(10). The products can be further converted to 2-aminothiophenes 4, either stepwise or in situ, to show the versatility of the method (Scheme).…”