Process of making optically pure L-pipecolic acid and process of making anesthetics and intermediates therefrom
The present invention describes a novel process of preparation of optically pure L-Pipecolic acid and an improved process for the conversion of L-pipecolic acid to L-N-(2,6-dimethylphenyl)-1-propyl-2-piperidinocarboxamide, its hydrochloride salt and hydrochloride monohydrate.
1. A process for the preparation of pure L-N-pipecolylxylidide, comprising:
(a) preparing L-pipecolic acid chloride hydrochloride from pure L-pipecolic acid hydrochloride phosphorous pentachloride at a temperature range of about −30° C. to 20° C.; and
(b) reacting the L-pipecolic acid chloride hydrochloride obtained in step (a) with xylidine at a temperature range of about −30° C. to 20° C. to produce optically pure L-N-pipecolylxylidide.
2. The process of claim 1 , further comprising the step of making an anesthetic from the L-N-pipecolylxylidide obtained in step (b).
3. The process of claim 2 , wherein the anesthetic is L N-pipecolylxylidide having the structure