GB580509A - Process for the manufacture of pantothenic acid and its salts - Google Patents

Abstract

Pantothenic acid is prepared by the action on d(+)-a : g -dihydroxy-b b -dimethyl butyric acid-(3 : 31-dihydroxybutyl) amide or its derivatives diacylated in the acid radical of oxidizing agents which can be employed for the transformation of a glycol into the corresponding carboxylic acid containing one carbon atom less. For this purpose, permanganic acid and its salts are particularly suitable. If there are employed oxidizing agents such as periodic acid or lead tetra-acetate which can be employed for the oxidation of a diglycol with adjacent hydroxy groups, one of which is terminal to the corresponding aldehyde containing one carbon atom less there may be obtained as an intermediate product d(+)-a : g -dihydroxy-b b -dimethyl-butyric acid-(31-oxopropyl)-amide. The further oxidation of this compound to pantothenic acid is preferably carried out with silver oxide in the presence of alkali metal or alkaline earth metal hydroxides. In examples: (1) d(+)-a : g -Dihydroxy-b b -dimethyl-butyric acid-(31-41-dihydroxybutyl) amide is treated with barium permanganate in the presence of dilute aqueous sulphuric acid at 15-20 DEG C., and the reaction product worked up to give pantothenic acid which is separated in the form of its cinchonidine salt. Instead of the chonidine salt, the benzyl-thiuronium salt may be prepared. (2) d(+)-a : g -Dihydroxy - b b - dimethyl - butyric acid - (31 : 41-dihydroxybutyl) amide is treated with barium permanganate in aqueous solution in the presence of precipitated barium carbonate to give the barium salt of pantothenic acid. (3) d(+) - a : g - Dihydroxy - b b - dimethyl - butyric acid-(31 : 41-dihydroxybutyl)-amide is treated with aqueous potassium periodate at a temperature below 30 DEG C. to give a : g -dihydroxy-b b -dimethyl-butyric acid-(31-oxypropyl)-amide. This compound is mixed with silver oxide and treated with saturated aqueous barium hydroxide to form barium d(+)-pantothenate, which is purified by means of its benzyl-thiuronium salt. In the silver oxide oxidation calcium hydroxide may be used instead of barium hydroxide to form the corresponding calcium salt. (4) d-a : g -Dihydroxy-b b -dimethyl-butyric acid-(31 : 41-dihydroxybutyl) amide is treated with 10 per cent aqueous periodic acid solution, and then neutralized with barium carbonate to form d - (+) - a : g - dihydroxy - b b - dimethyl - butyric acid-(31-oxopropyl) amide which is then converted into pantothenic acid as in example (3). Specification 568,355 is referred to.