GB757704A - Improvements in amino derivatives of n-alkyl substituted aspartic acids and their functional derivatives - Google Patents

Abstract

The invention comprises compounds of formula <FORM:0757704/IV(a)/1> wherein X is an alkylene group which interposes 2 or 3 carbon atoms directly between the nitrogen atoms; R1 is hydrogen or a group H2N-X-; and R2 is hydrogen, sodium or an alkyl radical containing up to 18 carbon atoms. The compounds are prepared by reacting equimolar proportions of an alkylene polyamine H2N-X-NH-(X-NH)n-H (wherein n is 0 or 1) with a dialkyl (preferably diethyl) ester of maleic acid at a temperature below 50 DEG C., completing the reaction at 50-100 DEG C. and, if desired, saponifying the ester groups with caustic soda and recovering the corresponding sodium salts, from which the free acids may be obtained by acidification or ion exchange. The reaction is preferably conducted in a solvent such as benzene, toluene, dioxane or tertiary butamol. Amine starting materials are, for example, ethylene diamine, isopropylene diamine, trimethylene diamine, 1.3-diaminobutylene, 1.2-diaminobutylene, diethylene triamine, di-isopropylene triamine and di-(trimethylene) triamine. The examples describe the preparation of N-(2-aminoethyl)-, N-(2-aminoisopropyl)-, and N-(2-(2-aminoethyl)-aminoethyl)-aspartic acid, and the sodium salts and diethyl esters thereof. Specification 483,224, [Group IV], is referred to.