THE STRUCTURE OF ABACAVIR (SYSTEMATIC NAME: {(1S,4R)-4-[2-amino-6-(cyclo-propyl-amino)-9H-purin-9-yl]cyclo-pent-2-en-1-yl}methanol), C(14)H(18)N(6)O·2.5CH(3)OH, consists of hydrogen-bonded ribbons which are further held together by additional hydrogen bonds involving the hydroxyl group and two N atoms on an adjacent purine. The asymmetric unit also contains 2.5 mol-ecules of methanol solvate wh...