Patent ID: 7700646

Claim:
A compound of the formula I in which R 8 to R 10 are individually selected from the group consisting of hydrogen, aryl, C 1-6 alkyl, trialkylsilyl and acyl; R 1 to R 5 are selected from hydrogen or hydroxyl; R 6 and R 7 are each selected from the group consisting of H, C 1-4 alkyl, trialkylsilyl and acyl; X is O or NR, and R is H or Me; in which any of the alkyl groups including alkyl groups in alkoxy, acyl and acyloxy groups may be substituted by one or more aryl, C 1-4 alkyl, C 1-4 alkoxy, hydroxyl, trialkylsiloxy or acyloxy groups; and wherein (I) R 2 is OH, and in which R 4 is H or OH and R 1 , R 3 and R 5 are H; or (II) R 3 is OH and the remainder of R 1 -R 5 are H; or (III) four of R 1 -R 5 are OH.