An Efficient, Optimized Synthesis of Fentanyl and Related Analogs
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.