1169-70-6

The agonistic activity of fluorinated and nonfluorinated fentanyl analogs on μ-opioid receptor was investigated using a cell-based assay system. Based on the activity, fentanyl analogs were ranked as follows: fentanyl>isobutyrylfentanyl≈butyrylfentanyl≈methoxyacetylfentanyl>acetylfentanyl. However, among the fentanyl analogs fluorinated on the Nphenyl ring, 2-fluoro analogs and 3-fluoro analogs showed the strongest and weakest activities, respectively. These results suggest that the 2-fluorinated isomers of fentanyl analogs are more likely to cause poisoning.

Natural abundance carbon-13 chemical shifts are reported for the hydrochloride salts of fentanyl and fifteen analogs. The signals are assigned on the basis of chemical shift theory, SFORD multiplicities, signal intensities, comparisons with model compounds, and thiophene carbon-proton coupling constants. In addition to its forensic value, the data suggest that the solution conformations of the analogs are similar to that of fentanyl hydrochloride.