ethyl 4-(7-chloro-4-oxoquinazolin-3-yl)butanoate ethyl 4-(7-chloro-4-oxo-quinazolin-3-yl)butanoate 4-(7-chloro-4-oxo-3-quinazolinyl)butanoic acid ethyl ester 4-(7-chloro-4-keto-quinazolin-3-yl)butyric acid ethyl ester