Patent ID: 8143396

Claim:
A compound of the formula: wherein: A is (CR 1 R 2 ) n ; R 1 is independently H, —OR 3 , —NHR 4 , C 1 -C 4 alkyl; or when n is 2, adjacent R 1 can together define an olefinic bond; R 2 is H; or when R 1 and R 2 form gem substitution on the same carbon and R 1 is C 1 -C 4 alkyl, then R 2 is C 1 -C 4 alkyl; or when R 1 and R 2 form gem substitution on the same carbon and R 1 is OR 3 , then R 2 is —C(═O)OH, or a pharmaceutically acceptable ester thereof; R 3 is independently H, or a pharmaceutically acceptable ester thereof; R 4 is independently H, or a pharmaceutically acceptable amide thereof; Rs 1 is H or a hydroxy protecting group selected from methyl, ethyl, isopropyl, benzyl, triphenylmethyl, tetrahydropyranyl, 4-methoxyphenyl-diphenylmethyl, 2,2,2-trichloroethyl, trimethylsilyl, t.butylsilyl, t.butyldiphenylsilyl, acetyl, propionyl and benzoyl; Rs 2 is H or an amino protecting group selected from benzyloxycarbonyl, substituted benzyloxycarbonyl, 9-fluorenylmethyloxycarbonyl, tert.butyloxycarbonyl, ethoxycarbonyl, diisopropylmethoxycarbonyl, allyloxycarbonyl, cyclopentyloxycarbonyl, adamantyloxycarbonyl, triphenylmethyl, benzyl, trimethylsilyl, phenylthiocarbonyl and dithiasuccinoyl; n is 1, 2 or 3; and pharmaceutically acceptable salts thereof.