Patent ID: 8026229

Claim:
A compound of formula I, wherein R 1 is C 1 -C 4 acyl, R 2 is H, methyl, C 1 -C 4 acyl, or benzoyl, R 3 is C 1 -C 4 alkyl or a group of formula C n F m H o , n is 1, 2, 3, 4, 5 or 6, m is >1, m+o is 2n+1, R 4 and R 5 are both H, or together are a methylene or an additional double bond, R 6 is H, and R 7 is OC 1 -C 11 -acyl or OSO 2 NR 1 R 2 , wherein the dashed lines in formula I represent up to two double bonds.