The mol. electrostatic potential of fentanyl derivatives (I; R = H, methoxymethyl) was studied. There was a broad neg. elec. potential area surrounding the amide oxygen atom. The introduction of a methoxymethyl group into the 4-position of piperidine ring increased a new neg. elec. potential area. The aromatic ring on the 1-position of piperidine ring possessed a broad pos. elec. potential area. The amide nitrogen atom and the piperidine nitrogen atom were surrounded by smaller neg. elec. potential areas. Based on the calculated electrostatic potential, the possible mechanisms of analgesic action and toxicity for these compounds can be predicted in relation to their chem. structures.

Key words: TOXICITY, FENTANYLUM, ANESTHETICS, CNDO APPROXIMATION, STRUCTURE AND PROPERTY CORRELATION, WAVE FUNCTIONS, PIPERIDINE, ANALGESICS, COMPUTATIONAL CHEMISTRY, MOLECULAR ELECTROSTATIC POTENTIAL