Patent ID: 7642290

Claim:
A compound of formula I: wherein: the dotted line represents a single or a double bond; R 1 and R 2 are the same or different and, independently of each other, are groups represented by the formula: in which R 5 is H, OH or OR 6 , where R 6 is a linear or branched C 1 -C 4 alkyl; A-B is a group represented by the formula: and X is, —CH 2 O—, —CH 2 CH 2 O—, —CH(CH 3 )CH 2 O— or —CH 2 CH(CH 3 )O—; Z is —CH 2 CH 2 O—, —CH(CH 3 )CH 2 O— or —CH 2 CH(CH 3 )O—; m is 1, and n is an integer of 1-50 and salts thereof.