Synthesis of Flavonoid Sulfates. III. Synthesis of 3′,4′-ortho Disulfates Using Sulfur Trioxide-trimethylamine Complex, and of 3′-SuIfates Using Aryl Sulfatase

Abstract

Abstract A number of flavonoid 3′,4′-disulfates were synthesized from the corresponding 4′-sulfate esters, using sulfur trioxide-trimethylamine complex. Desulfation of the sulfate esters using aryl sulfatase demonstrated that the rate of hydrolysis of the 3′-sulfate group was slower than either the 7- or 4′ groups, thus allowing the specific synthesis of flavonol 3,3′-disulfates. The effects of ortho-disulfation on the 13C NMR spectra of flavonoids, and the regative FAB-MS spectra of diand trisulfated flavonoids are discussed.