2-Hydrazino-4-hydroxy-5H-[1]-benzopyrano-[4, 3-d]-pyrimidin-5-one (3) was p
repared via condensation of 2 with hydrazine hydrate. Treatment of 3 with m
ethylene chloride, ethyl chloroformate, ethyl chloroacetate and benzaldehyd
e yielded the corresponding 2 - ( substituted) hydrazino - 4 - hydro-xy-5H-
[1]-benzopyrano-[4, 3-d]-pyrimidin-5-one (4, 5, 6, and 10), followed by cyc
lization of 4, 5 and 6 with dimethyl formamide and fused sodium acetate und
er reflux, while compound 10 was cyclized with bromine and sodium acetate i
n acetic acid. Compound 3 reacted with beta-(toloyl) acrylic acid, ethyl al
pha-cyano-p-methoxycinnamate, diethyl malonate and acetyl chloride affordin
g the corresponding 2-(substituted) hydrazino-4-hydroxy-5H-[1]-benzopyrano-
[4, 3-d]-pyrimidin-5-one (12, 13, 14, 15 and 16).