CONFORMATIONAL COMPARATIVE-ANALYSIS OF 2',3'-DIDEOXYTHYMIDINE ANALOGSBY MOLECULAR MECHANICS CALCULATIONS (CHEM-X) AND BY SEMIEMPIRICAL METHODS (AM1)

The conformations of 2',3'-dideoxynucleoside analogues with known anti viral activity have been studied by molecular mechanics (MM) and molec ular orbital (MO) calculations. In accordance with results already rep orted, the parameters P and theta(m) were found by the AM1 method, whi ch differed from the experimental results. By MM calculations, however , the results obtained corresponded with those expected. Hence, MM cal culations provided adequate geometries for those compounds which may b e also studied by MO calculations in order to determine their electros tatic properties. The geometrical and electrostatic data were compared with the experimental results obtained by crystallographic analysis a nd by H-1 NMR.