Abstract
The reactions of 2-benzamido(and acetamido)-3-cyano-4, 5-dihydrothiophenes (Ia and Id) with ethyl cyanoacetate or malononitrile gave ethyl α-cyano-4-[2-phenyl(and methyl)-5, 6-dihydrothieno-[2, 3-d]pyrimidine]acetates (IIa-1 and IId-1) or 4-[2-phenyl(and methyl)-5, 6-dihydrothieno[2, 3-d]pyrimidine]malononitriles (IIa-2 and IId-2). Similarly, 2-benzamido(and acetamido)-3-cyano-5-methyl(or 4-phenyl)-4, 5-dihydrothiophenes (Ib, e or Ic, f) reacted with ethyl cyanoacetate or malononitrile to form the corresponding ethyl cyanoacetate derivatives (IIb, c-1, IIe, f-1) or malononitrile derivatives (IIb, c-2, IIe, f-2). Compounds IIa-f-1 and IIa-f-2 were prepared by the reactions of the corresponding 4-chloro-5, 6-dihydrothieno[2, 3-d]pyrimidines and ethyl cyanoacetate or malononitrile.
