Patent ID: 6984754

Claim:
A compound of the Formula I wherein: R 1 is (CH 2 ) m CH 3 where m is 0 or an integer in the range from 1 to 16, or an alkenyl, alkynyl, alkoxy, alkylthio, or alkyl sulfinyl group having from 2 to 17 carbon atoms, wherein R 1 may be optionally substituted with one or more substituents selected from hydroxy, aldehyde, oxo, lower acyloxy, halogen, thio, sulfoxide and sulfone, R 2 is H, CH 3 or CH 2 CH 3 , R 3 is H or CH 3 , R 4 is H or CH 3 , n is an integer in the range from 1 to 3, X is carboxyl (COOH), and R 1 , R 2 and R 3 are each different so that the carbon atom to which they are attached is chiral and the compound of Formula I is a substantially pure enantiomer in the R or S configuration or a pharmaceutically acceptable salt thereof.