Pteridines XCVIII. Synthesis and Properties of 1-Methylpterins

Abstract

A series of 1-methyl-pterin derivatives (6-13) have been synthesized by condensation and methylation reactions. The compounds have been characterized by elemental analyses, pKa deterimations and UV spectra. Comparisons of the physical data of the corresponding N-1 and N-3 methyl-pterins indicate why the normal pterins exist in aqueous solution preferentially in the N3-H tautomeric configuration. The thermodynamical stability of the lactam group forces the acidic H-atom to adapt the nitrogen adjacent to the carhonyl function but no other vinylogous position. A lactam group does not participate in heteroaromatic cyclic resonance, in general.

Keywords

• i-methylpterins
• elemental analyses. pka
• detemlinations. uv spectra