STUDIES ON KETEN AND ITS DERIVATIVES .88. ETHYL 5-OXO-4-OXASPIRO[2,3]HEXANE-1-CARBOXYLATE - SYNTHESIS AND REACTIONS

Photoreaction of diketen with ethyl diazoacetate gave ethyl cis- and trans-5-oxo-4-oxaspiro[2,3]hexane-1-carboxylate (1). Ethanolysis of compound (1) with hydrogen chloride at room temperature gave diethyl 3-oxohexane-1,6-dioate (4). Heating of compound (1) with sodium hydroxide in ethanol gave 5-ethoxycarbonyl-4-oxopentanoic acid (5). Reaction of (1) with phenols gave the coumarin derivatives (7a and b). Reaction of (1) with anilines gave the 5-carbamoyl-4-oxopentanoate derivatives (2c and d). Compound (1) reacted with phenylhydrazine, hydroxylamine, and acetamidine to give the pyrazolone (10), isoxazolone (11), and pyrimidone derivative (12), respectively.