2-(1-Piperazinyl)ethyl 4-oxo-4H-1-benzopyran-2-carboxylate 32773-98-1 4-Oxo-4H-1-benzopyran-2-carboxylic acid 2-(1-piperazinyl)ethyl ester 4H-1-Benzopyran-2-carboxylic acid, 4-oxo-, 2-(1-piperazinyl)ethyl ester