Читать книгу Routes to Essential Medicines - Peter J. Harrington - Страница 83

Anesthetics, Preoperative Medicines, and Medical Gases/Local Anesthetics

A piperidine is often formed by catalytic hydrogenation of a pyridine. Palladium, platinum, rhodium, ruthenium, and nickel catalysts have all been used. The hydrogenation is often run under acidic conditions to prevent catalyst deactivation by the piperidine product.

Discussion. Bupivacaine is a 1 : 1 mixture of enantiomers. Levobupivacaine, the (S)‐enantiomer, is also manufactured for clinical use. The tertiary amine of bupivacaine is formed in the final step by N‐alkylation of the secondary amine with 1‐bromobutane. The amide is formed from 2,6‐dimethylaniline (2,6‐xylidene) and the acid chloride. Pipecolic acid chloride hydrochloride is formed from pipecolic acid. Pipecolic acid is formed by catalytic hydrogenation of 2‐picolinic acid.