Reactions of Benzylcarbonyl Compounds with Formamide. IV

Abstract

Heating of α-acyl-3, 4-methylenedioxyphenylacetonitriles (I) with H₂NCHO and POCl₃ afforded pyrimidines (II) and enamines (III), the intermediate of pyrimidines, but isoquinolines were not isolated. Thus α-formyl derivative (Ia) gave 4-amino-5- (3', 4'-methylenedioxyphenyl) pyrimidine (IIa), α-acetyl derivative (Ib) gave β-amino-α- (3, 4-methylenedioxyphenyl) crotononitrile (IIIb), but under more drastic conditions Ib or IIIb gave 4-amino-6-methyl-5- (3', 4'-methylenedioxyphenyl) pyrimidine (IIb), and α-benzoyl derivative (Ic) gave 4-amino-5- (3', 4'-methylenedioxyphenyl) -6-phenyl-pyrimidine (IIc), and β-amino-α- (3', 4'-methylenedioxyphenyl) cinnamonitrile (IIIc), but under more drastic conditions Ic or IIIc gave only IIc. 3, 4-Methylenedioxyphenylacetonitrile (IV) gave IIa and 3, 4-methylenedioxyphenylacetamide (V) under the same reaction conditions.