1H-Cyclopenta(b)quinoxaline-1,3-dicarboxylic acid, 2,3-dihydro-, diethyl ester 2,3-Dihydro-1H-cyclopenta(b)quinoxaline-1,3-dicarboxylic acid diethyl ester 5-25-06-00040 (Beilstein Handbook Reference) 6635-26-3 BRN 0341592 NSC 16963