Synthesis and Antiradiation Activity of Some Sulfur Containing Thiophene Derivatives

Abstract

Condensation of 2-(2,2-dicyano-1-methylvinyl)thiophene (2) with phenylhydrazine furnished the corresponding 2-(1-phenylhydrazonoethyl)-thiophene (4). Compound (4) was obtained also via reaction of (1) with phenylhydrazine. Reaction of (2) with amines gave 2-(2,2-dicyano-1-ethylamino or benzylamino- 1 methylethyl)thiophene (5a,b). Treatment of (2) with elemental sulfur yielded directly the cyclised product 2-(5-amino-4-cyano-3-thienyl)thiophene (6). On the other hand refluxing (2) in pyridine with carbon disulfide gave the pyridine-1,3-dithione derivative (7). Condensation of (2) with phenyl isocyanate and/or phenyl isothiocyanate afforded 6-amino-4-(2-thienyl)-1,2-dihydro-2-oxo- 1-phenylpyridine-5-carbonitrile (9) and/or 5-(2-thienyl)-2,7-dithioxo-3,8-N-phenyl-1,2,3,7,8-pentahydropyrido[2,3-d]pyrimidine-4-imine (11). Also the dicyano derivative (2) when reacted with cinnamonitrile (12) afforded the 2-(3-amino-2,4-dicyano-5-arylphenyl)-thiophenes (15a-d). Conversion of (15b) into the polyazanaphthalene (17) and (18) was affected via cyclocondensation with phenyl isocyanate and/or phenyl isothiocyanate. Compound (15a) showed promising antiradiation activity.

Keywords::

• Thiophene derivatives
• antiradiation activity