Steroid conjugates. V.1 The synthesis of a suifoglucuronide derivative of estriol

The di-potassium salt of estriol-3-sulfate-16-glucuronide [17β-hydroxy-3-sulfooxyestra-l,3,5(lO)-trien-16α-yl-β-=D-glucopyrano-siduronic acid di-potassium salt] ( 11 ) has been synthesized by a pathway utilizing the direct condensation of methyl (2,3,-tri-O-acetyl-α-bromo-=D-glucopyranosid)ronate with estriol-3-benzyl ether ( 2 ). The structure of this intermediate, methyl (3-benzyloxy-17β-hydroxyestra-l,3,5(lO)-trien-16α-yl-2',3',4'-tri-O-acetyl-β-D-glucopyranosid)ronate ( 3 ) was unequivocally confirmed by its synthesis from methyl (3Ubenzyloxyestra-l,3,5(lO)-trien-17-on-16α-yl-2',3',4'-tri-O-acetyl-β-=D-glucopyranosid)ronate ( 5 ). Selective removal of the benzyl group followed by sulfation with triethylaminesulfur trioxide afforded the key compound, methyl (17β-acetoxy-3-triethylammoniosulfooxyestra-l,3,5(lO)-trien-16α-yl-2',3',4'-tri-O-acetyl-β-=D-glucopyranosid)ronate ( 10 ). Basic hydrolysis gave the sulfoglucuronide as its di-potassium salt.