The synthesis of thiazoles and thiophenes starting from nitriles, via a modified Gewald reaction has been studied for a number of different substrates. 1,4-Dithiane-2,5-diol was used as the aldehyde precursor to give either 2-substituted thiazoles or 2-substituted aminothiophenes depending on the substitution of the α-carbon to the cyano group.

Novel 3-acetyl-2-aminothiophenes were prepared from cyanoacetone and 1,4-dithianyl-2,5-diols using a modified Gewald reaction. The syntheses of the corresponding acetamides, as well as that of 3-acetyl-2-amino-5-nitrothiophene - an interesting building-block for thiophene azo dyes - are reported. Detailed spectroscopic investigations ((1)H-NMR, (13)C-NMR, MS, IR) of the obtained compounds are p...

Ethyl-2-amino-4,5,6,7-tetrahydro-1-benzoselenophene-3-carboxylate (4), has been prepared as a potential dual-acting selenium-containing allosteric enhancer of adenosine A(1)A receptor binding utilising a modified Gewald reaction. While preliminary testing indicated that 4 is a superior enhancer of A(1)AR binding than its thiophene counterpart, its instability under mildly acidic conditions is c...

The title compound, C(9)H(10)N(2)S, was synthesized according to Gewald procedures by the reaction of cyclo-hexa-none with malonitrile and sulfur in the presence morpholine. The cyclo-hexane ring adopts a half-chair conformation and the thio-phene ring is essentially planar (r.m.s. deviation = 0.05 Å). The crystal packing is stabilized by two inter-molecular N-H⋯N hydrogen bonds, which link the...

2-Amino-3-functionally substituted thiophene de­ rivatives are important intermediates to the phar­ maceutically important thieno[2,3-d]pyrimidines [2]. These thiophene derivatives were available from the procedures published by K. Gewald [3, 4] via either the reaction of a-methylene ketones with active methylene nitriles in presence of elementary sulphur of from a-mercaptoketones and active me...