Patent ID: 7309793

Claim:
A compound of <Formula 1> wherein X is O, S or NCN; R 1 is NO 2 , NH 2 , H, CN, NHCOCH 3 , NHCOCF 3 or NHSO 2 CH 3 ; R 2 is or CH 2 OR a wherein, R a is C 1 ˜C 4 straight or branched alkyl; and Z is C 2 ˜C 6 straight or branched alkyl; R 3 is OH or OCOCH 3 ; R 4 is C 1 ˜C 4 straight or branched alkyl; R 5 and R 6 are independently H, C 1 ˜C 4 straight or branched alkyl, alkoxy or halogen; and * represents a chiral carbon, an enantiomer, a diastereomer, a racemic mixture or a pharmaceutically acceptable salt thereof.