The Synthesis of 2-Amino 7-Substituted Purines

The putative antiviral agent, (S)-2-amino-7-(2,3-dihydroxy-propyl) purine (1b), and its achiral analogue, 2-amino-7-(2-hydroxyethyl) purine (2), were synthesized by a procedure involving alkylation at N7 of guanosine followed by deribosylation and deoxygenation. Evidence for the stereochemical integrity of the former preparation was obtained from the X-ray diffraction structure of the novel tricyclic compound, (S)-6H, 7H, 8H-2-amino-7-hydroxy-[1,4] oxazepino [1,2,3-d, elpurine (17, obtained by a similar synthetic sequence. Compound (1a), a regioisomer of the known antiviral agent, (S)-9-(2,3-dihydroxypropyl) adenine ((S)-DHPA), was tested and found to be inactive in tissue culture against herpes virus type-2, rotavirus, poliovirus, and parainfluenza virus.