4-Amino-3-phenyl-2-thioxothiazol-5-carboxam(i1d)e r eacts with aromatic aldehydes to form thiazolopyrimidines
(2a,b)r and with acetic anhydride to thiazolopyrimidine (2J. Thiazolocarboxamides ( ls,J
were converted to thiazolotriazines (3a,b) by reaction with nitrous acid. When thiazolopyrimidine (2,)
was refluxed with POCl,, the corresponding chlorothiazolopyrimidine (4) was isolated. The produced
chloro compound (4) can be converted into the corresponding thiazolopyrimidindithiones (5) or substituted
aminothiazolopyrimidines (6,7), when allowed to react either with thiourea, aromatic amine
or hydrazine hydrate. S-alkylated thiazolopyrimidines (SJ were produced when compound (5) was
reacted with halo compounds or acrylonitrile. Hydrazino compound (7) reacts with acetylacetone to
produce the pyrazolylthiazolopyrimidine (9).