| abstract |
A compound of formula IIIn nwherein n(1) when n signifies 2, R 4 signifies hydrogen, alkyl group or alkylaryl group; R 5 signifies a hydroxyl protecting group and R 6 signifies an amino protecting group; or n(2) when n signifies 3, R 5 signifies a hydroxyl protecting group; and R 4 and R 6 taken together represent a phthalimido group nand wherein the hydroxyl protecting group is an organosilyl group; the amino protecting group is an alkyl carbamate or alkylaryl carbamate group; the term alkyl means hydrocarbon chains, straight or branched, containing from one to six carbon atoms, optionally substituted by aryl, alkoxy, halogen, alkoxycarbonyl or hydroxycarbonyl groups; the term aryl means a phenyl or naphthyl group, optionally substituted by alkoxy, halogen or nitro group; and the term halogen means fluorine, chlorine, bromine or iodine. |