Patent ID: 8058435

Claim:
An intermediate of the following (I) in which R 1 and R 2 represent independently of each other a C 1 -C 12 alkyl group, a (C 1 -C 12 alkoxy)carbonyl group, optionally substituted by one, two or three halogen atom, a (C 2 -C 12 alkenyloxy) carbonyl group, an acyl group, an aryl(C 1 -C 12 )alkyl group, an arylalkoxy carbonyl group, a (C 1 -C 12 alkyl)sulfonyl group or an arylsulfonyl group, R 3 represents an O-protecting group, R 4 and R 5 represent independently of each other a hydrogen atom or an O-protecting group, R 6 represents an O-protecting group and R 7 represents a C 1 -C 12 alkyl group or â€”OR 6 and â€”OR 7 form together a group â€”OCH 2 Oâ€”.