Pteridines LXXXV. Chemical Synthesis of Deoxysepiapterin and 6-Acylpteridines by Acyl Radical Substitution Reactions

Article abstract of DOI:10.1002/hlca.19880710305

A new synthesis of deoxysepiapterin (2), one of the two yellow eye pigments of the Drosophila mutant sepia, is described.The synthetic approach makes use of a homolytic nucleophilic acylation of 7-(alkylthio)pteridine derivatives (11, 13, 15, 18, 20) leading to the corresponding 6-acyl derivatives (21, 27).Desulfurizations have been achieved for the first time in the pteridine series using Raney-Co, Raney-Cu, or Cu-Al alloy in alkaline medium.Besides cleavage of the C(7)-S bond, further reductions of the C=O group at C(6) and the C(7)=N(8) bond are detected as side reactions leading to 6-(1-hydroxyalkyl) (34, 35, 42, 43) and 6-acyl-7,8-dihydro derivatives (2, 36, 37), respectively.The newly synthesized compounds have been characterized by chemical analysis, pK determination, UV and 1H-NMR spectra.