Synthese von 2,4‐Diamino‐thieno[2,3‐ d ]pyrimidin‐Derivaten

Synthesis of 2,4‐Diamino‐thieno[2,3‐ d ]pyrimidines Condensation of 2‐aminothiophene‐3‐carbonitrile ( 4 ) with guanidine or sequential addition of CS 2 and NH 3 to 4 provides 2,4‐diaminothieno[2,3‐ d ]pyrimidine ( 7 ). This compound yields, after sequential addition of sec ‐BuLi and either [3‐(trifluoromethyl)benzene]sulfenyl chloride ( 8 ) or the corresponding disulfide 9 , followed by acidic work up, 2,4‐diamino‐6‐{[3‐(trifluoromethyl)phenyl]thio}thieno[2,3‐ d ]pyrimidine ( 10 ). In another approach, 2‐amino‐5‐{[3‐(trifluoromethyl)phenyl]thio}thiophene‐3‐carbonitrile ( 11 ) obtained from 4 and 8 is transformed to 10 by condensation with guanidine. Corresponding to the second route, 2,4‐diamino‐6‐[(naphth‐2‐yl)thio]thieno‐[2,3‐ d ]pyrimidine ( 16 ) is synthesized. Oxidation of 10 with m ‐chloroperbenzoic acid gives 2,4‐diamino‐6‐{[3‐(tri‐fluoromethyl)phenyl]sulfinyl}thieno[2,3‐ d ]pyrimidine ( 13 ).