Figure 1.
Various commonly administered opioids: (1) morphine, (2) Tramadol, (3) Demerol, and (4) fentanyl.
Figure 2.
Fentanyl analogs and their potencies relative to morphine.
Figure 3.
Fentanyl analogs synthesized in this work.
Figure 4.
Synthesis of fentanyl and acetylthiofentanyl.
Yields reflect the isolated materials by column chromatography after each step and using the optimized conditions (cf. Table 1). Citrate and hydrochloride salts for each analog were obtained in nearly quantitative yields by treating the free bases at the end of these routes with the corresponding acids.
Figure 5.
Synthesis of thiofentanyl and acetylthiofentanyl.
Yields reflect the isolated materials by column chromatography after each step and using the optimized conditions (cf. Table 1). Citrate and hydrochloride salts for each analog were obtained in nearly quantitative yields by treating the free bases at the end of these routes with the corresponding acids.
Table 1.
Optimization steps for the synthesis of fentanyl (4); aisolated yield; balkylation in the synthesis of thiofentanyl derivatives; creductive amination.