APPLICATION OF THE VILSMEIER FORMYLATION IN THE SYNTHESIS OF 11-(13)C LABELLED IRIDOIDS

Article abstract of DOI:10.1016/S0040-4020(01)81508-8

The Vilsmeier reaction was utilized for the introduction of C-11 into iridoid glucosides, Aucubin hexaacetate (3a). 6,10-dideoxy aucubin tetraacetate (6a) and 8(S)-6,10-dideoxy-7,8-dihydro aucubin tetraacetate (7a) were used as substrates for the reaction. 6a and 7a were prepared by catalytic transfer hydrogenation of 3a with formic acid and Pd/C.The Vilsmeier reaction conditions were optimized with regard to the economic use of <(13)CHO>--DMF in the synthesis of <11-13C>-iridotrialglucoside (9).Remarcably, 5percent of the label in the product turned out to be situated at C-3.