Patent ID: 7030122

Claim:
A compound represented by A: wherein X represents O or S; Ar represents an optionally substituted aryl group, wherein any substituents are selected from the group consisting of halogen, azide, alkyl, alkenyl, alkynyl, hydroxyl, alkoxyl, amino, nitro, sulfhydryl, imino, and amido; Ar′ represents an aryl group substituted with one or more substituents selected from the group consisting of halogen, azide, alkenyl, alkynyl, hydroxyl, alkoxyl, amino, nitro, sulfhydryl, imino, and amido; R represents independently for each occurrence H or alkyl; R′ represents H, alkyl, or aralkyl; k is 0, 1, 2, or 3; n is 1, 2, 3, 4, 5, 6, 7, or 8; said aryl group is a radical of phenyl, naphthalene, anthracene, pyrene, pyrrole, furan, thiophene, imidazole, oxazole, thiazole, triazole, pyrazole, pyridine, pyrazine, pyridazine or pyrimidine; and the stereochemical configuration at a stereocenter in a compound represented by A is R, S, or a mixture thereof.