.alpha.-(Diethylphosphono)butanoic acid, ethyl ester 17145-91-4 Butanoic acid, 2-(diethoxyphosphinyl)-, ethyl ester Butyric acid, 2-phosphono-, triethyl ester Ethyl 2-(diethylphosphono)butyrate NSC22423 Triethyl 2-phosphonobutanoate Triethyl 2-phosphonobutyrate