Scheme 5.
Attempted synthesis of a dideazapurine analog: Reagents and conditions: (a) Hydrazine, Ru/C, EtOH, reflux, 3 h; (b) formic acid, reflux, 18 h; (c) TAR, BSA, TMSOTf, MeCN, reflux, 3 h; (d) NH3/MeOH; (e) Me2C(OMe)2, p-TsOH, 55 °C, 2 h; (f) TBSCl, imid., CH2Cl2; (g) Fe, FeSO4, MeOH/H2O, 50 °C, 2 h; (h) Boc2O, DMAP, Et3N, DMF; (i) TBAF, THF; (j) MsCl, Et3N, CH2Cl2; (k) MeNH2/EtOH, 50 °C, 18 h; (l) 13, NaI, Et3N, MeCN, rt, 6 h.