Efficient Syntheses of Pyrofolic Acid and Pteroyl Azide, Reagents for the Production of Carboxyl-Differentiated Derivatives of Folic Acid
journal contributionposted on 22.10.1997, 00:00 authored by Jin Luo, Michael D. Smith, Douglas A. Lantrip, Susan Wang, P. L. Fuchs
Reaction of folic acid (1) with excess trifluoroacetic anhydride provides access to both the previously unknown N10-(trifluoroacetyl)pyrofolic acid (8) and pyrofolic acid (9). Reaction of either of these materials with hydrazine selectively affords pteroyl hydrazide (13), which may be oxidized to pteroyl azide (27) on a large scale (62% overall from 1 without the need for chromatography). Treatment of 27 with differentially protected glutamates provides a convenient and high-yielding synthesis of differentially protected, optically pure folates.