4-Aminobutyric acid ethyl ester hydrochloride 6937-16-2 Butanoic acid, 4-amino-, ethyl ester, hydrochloride Butyric acid, 4-amino-, ethyl ester, hydrochloride DF 503 Ethyl .gamma.-aminobutyrate hydrochloride Ethyl.gamma.-aminobutyrate, hydrochloride NSC40245 WLN: Z3VO2 &GH