Molecular and crystalline structure of 3'-methylamino-2',3'-dideoxyribosylthymine--a potential inhibitor of HIV]

The structure of 3'-methylamino-2',3'-dideoxyribosylthymine ddT(3'NHMe)] was determined by X-ray analysis. The space group is P2(1)2(1)2(1). Cell dimensions are: a 5.132(1), b 13.718(1), c 16.947(2) A, V 1193.2 A3, Z 4. The structure was solved by directed methods and refined by the full-matrix least square method to R 4.8%. The molecule of ddT(3'NHMe) has anti-conformation with respect to the glycosidic bond (chi (O4'-C1'-N1-C2) = -106.7 degrees), C3'-endo-C4'-exo puckering of the sugar moiety (P -28.8 degrees, psi m -31.5 degrees) and gauche-gauche conformation about exocyclic C4'-C5' bond (psi(C3'-C4'-C5'-O5') 45.8 degrees). The structure of ddT(3'NHMe) was compared with those of 3'-amino-3'-deoxythymidine, 3'-azido-3'-deoxythymidine and natural thymidine.