Reductive acylation of the aliphatic diazo function. N-(2-Diazo-3-oxoalkanoyl)-glycine esters as synthetic precursors of [γ-(aryloxy)threonyl]glycine derivatives

Catalytic reduction of several N[2-diazo-3-oxo-4-(aryloxy)alkanoyl]glycine esters gives N-[2-hydrazono-3-oxo-4-(aryloxy)alkanoyl]glycine esters. A pyrazine is obtained by catalytic reduction in ethanolic hydrogen chloride of N-[2-diazo-3-oxo-4-(phenoxy)butanoyl]glycine ethyl ester. A two-step procedure involving reductive acetylation or trifluoroacétylation of the diazo function, and subsequent borohydride reduction of the keto group yields the corresponding acylamino alcohol derivatives.