Synthesis of some new fused coumarin derivatives

摘要

Abstract2‐Hydrazino‐4‐hydroxy‐5H‐1‐benzopyrano‐4,3‐d‐pyrimidin‐5‐one (3) was prepared via condensation of 2 with hydrazine hydrate. Treatment of 3 with methylene chloride, ethyl chloroformate, ethyl chloroacetate and benzaldehyde 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 cyclization of 4, 5 and 6 with dimethyl formamide and fused sodium acetate under reflux, while compound 10 was cyclized with bromine and sodium acetate in acetic acid. Compound 3 reacted with β‐(toloyl) acrylic acid, ethyl α‐cyano‐p‐methoxycinnamate, diethyl malonate and acetyl chloride affording the corresponding 2‐(substituted) hydrazino‐4‐hydroxy‐5H