Abstract: A glycinamide derivative of the general formula I: ##STR1## wherein: R is a linear or ramified alkyl group C.sub.5 -C.sub.18, a linear or ramified alkenyl group C.sub.5, C.sub.6, C.sub.7, C.sub.8, C.sub.9, C.sub.10, C.sub.11, C.sub.12, C.sub.13, C.sub.14, C.sub.15, C.sub.16, C.sub.17 or C.sub.18, a linear or ramified alkynyl group C.sub.4 -C.sub.10, a linear or ramified acyl group C.sub.4 -C.sub.18, a linear or ramified alkyl group C.sub.1 -C.sub.10, substituted by a phenoxy group, by a hydroxy radical, by an acetoxy radical, by a carboxy radical, by a linear or ramified alkoxycarbonyl group C.sub.1 -C.sub.4, by a carbonyl radical, by a carboxaldehyde group, by an acetal or cetal group, by one or more phenyl groups, by one or more phenyl groups substituted by a halogen atom such as fluorine, chlorine or bromine,R.sub.1 represents hydrogen, a linear or ramified alkyl group C.sub.1, C.sub.2, C.sub.3, C.sub.4, C.sub.5, C.sub.6, C.sub.7, C.sub.8, C.sub.9 or C.sub.10, a linear or ramified acyl group C.sub.1 -C.