Crystal structures ofN(6)-methyladenine hydrochloride andN(6),N(9)-dimethyladenine

The crystal structures ofN (6)-methyladenine hydrochloride (6-MA·HCl) and ofN (6),N (9)-dimethyladenine (6,9-DMA) were determined by the use of X-ray diffractometer data. Crystals of 6-MA·HCl are monoclinic, space groupP2₁/m, witha = 9.3450(6),b = 6.5838(4),c = 7.3142(3) Å, = 114.837(4) °, andZ = 2. Crystals of 6,9-DMA are monoclinic, space groupP2₁/c, witha = 12.045(3),b = 6.135(2),c = 23.27(1) Å, = 111.79(3), andZ = 8. The crystal structures were refined by least-squares toR = 0.053 for 6-MA·HCl andR = 0.071 for 6,9-DMA. The N(1)-protonated adenine derivative in the 6-MA·HCl crystal structure and the two crystallographically independent adenine derivatives in the 6,9-DMA structure all assume conformations in which the methyl substituent at N(6) is in or near the purine plane, and is pointing away from the imidazole moiety.