Zur Reaktion von α‐Oxo‐mercaptanen mit Nitrilen

Gewald reaction: synthesis, properties and applications of substituted 2-aminothiophenes

“…15 Many methods of synthesis of substituted 2-aminothiophenes published before the Gewald are generally unsuitable because they involve difficult preparation of the starting materials, multi step synthesis and do not produce high yields. 26 The prior to universal synthesis to this kind of product was reported in 1910 by Benary 27 as the multi step reaction of ethyl 4-chloro-2-cyano-3-oxobutanoate 1.…”

“…By this reaction polysubstituted 2-aminothiophenes 7 with electron-donating substitents in C-4 and C-5 positions of the thiophene ring (R 1 and R 2 , mainly alkyl and cycloalkyl chains) are prepared in yields varying between 35-80% (Table 1). 15,16,[28][29][30] Because of the instability and difficult preparation of the starting α-sulfanylcarbonyl compounds 5a this reaction appears to have a limited scope and more convenient variations are utilized instead of this procedure. 4 CO 2 Et 80 29…”

Synthesis of novel water soluble onium salts and thieno[3,4-c]thiolactones – precursors of conductive materials derived from substituted 2-aminothiophenes

“…Preparation of 2-aminothiophenes is a very simple, one-step reaction originally published by Gewald. 8 We have now synthesized three types of 2-aminothiophenes by two of procedures. In the first one we prepared 5-unsubstituted 2-aminothiophene derivative 1a by the procedure published in our earlier paper.…”

A Solvent-Free, One-Step, One-Pot Gewald Reaction for Alkyl-aryl Ketones via Mechanochemistry

“…Many of the methods reported involve difficult preparation of starting materials and multi-step synthesis. The most convenient method for preparing 2-aminothiophenes with a high degree of substitution is the Gewald reaction (Scheme 1) [9]. The Gewald method, involves the reaction of ketones, aldehydes or 1,3-dicarbonyl species with activated nitriles and elemental sulfur in the presence of an amine base.…”