2-Ethyl-4-(1-phenylethyl)-2H-pyrido(3,2-b)-1,4-oxazin-3(4H)-one monohydrochloride 2H-Pyrido(3,2-b)-1,4-oxazin-3(4H)-one, 2-ethyl-4-(1-phenylethyl)-, monohydrochloride 88799-57-9