152273-12-6 4-Dimethyl-3-t-butylcarboxyl-4,5-dihydro(1,5-a)imidazoquinoxaline Imidazo(1,5-a)quinoxaline-3-carboxylic acid, 4,5-dihydro-4,4-dimethyl-, 1,1-dimethylethyl ester U 93631 U-93631