Patent ID: 6528684
Filing Date: 2003-03-04
Classification: C07C

Abstract:
Process for the preparation of compounds with the formula: in whichY is hydrogen or one of the following groups: â€”R1, â€”COR1, â€”CSR1, â€”COOR1, â€”CSOR1, â€”CONHR1, â€”CSNHR1, â€”SOR1, â€”SO2R1, â€”SONHR1, â€”SO2NHR1, whereR1 is a straight or branched, saturated or unsaturated alkyl containing from 1 to 20 carbon atoms, optionally substituted with an A1 group, where A1 is selected from the group consisting of halogen, C6-C14 aryl or heteroaryl, aryloxy and heteroaryloxy, which can optionally be substituted with straight or branched, saturated or unsaturated lower alkyl or alkoxy, containing from 1 to 20 carbon atoms, halogens; said process comprises the following steps:a) conversion of D-aspartic or L-aspartic acid to N-Y substituted D-aspartic or L-aspartic acid; b) conversion of the Nâ€”Y substituted D-aspartic or L-aspartic acid to the respective anhydride; c) reduction of the anhydride obtained in step b) to the corresponding 3-(NHâ€”Y)-lactone; d) opening of the lactone obtained in step c) to yield the corresponding D- or L-3-(NHâ€”Y)-amino-4-hydroxybutyric acid; e) transformation of the 4-hydroxy group of the D- or L-3-(NHâ€”Y)-amino-4-hydroxybutyric acid into a leaving group; f) substitution of the leaving group in position 4 of the D- or L-3-(NHâ€”Y)-aminobutyric acid with a trimethylammonium group; g) hydrolysis of the ester group; and, if so desired, h) restoration of the amino group.