Intermediates of 13-thia-prostaglandin, their preparation and application to the synthesis of 13-thia-prostaglandin derivatives

摘要

Compounds of the formula IMAGE wherein A is C-C single bond, -CH2-, -CH(CH3)-, -C(CH3)2-, -CH2-CH2-, CH(CH3)CH2-, -C(CH3)2CH2-, -CH2-CH2-CH2- or -CH2O-; R1a and R1 each independently is hydrogen or a protective group which can be cleaved by solvolysis or by hydrogenolysis; R2 is H or alkyl of 1 to 3 C atoms; R3 is alkyl of 3 to 5 C atoms, phenyl or phenyl which is monosubstituted to trisubstituted by F, Cl, OH, OCH3, OC2H5, CF3 or alkyl of 1 to 3 C atoms, or, when A is not -CH2O-, can also be pyridyl, thienyl, naphthyl or alkoxy of 1 to 4 C atoms; indicates a bond in the beta -position and wavy line ( ) means that the bond can be in the alpha - or beta -position, are valuable intermediates for the stereospecific preparation of 13-thiaprostaglandin derivatives. The latter are prepared by U.V. irradiation of the former to first prepare the corresponding 2-oxa-3-OH-6-alkylthio-7-OH-1,5-bicyclo(3.3.0)octane derivative, which is then exposed to a Wittig reaction and, optionally, hydrogenation or oxidation inter alia to prepare members of the F1-, F2-, E1- and E2 series.