GB830866A - A process for the manufacture of tetrahydrofurfuryl-ammonium compounds - Google Patents

Abstract

Compounds of the general formula <FORM:0830866/IV (b)/1> (wherein the fragment -CH2-N(R1)(R2)(R3) in association with the anion A- represents a quaternized amino-methyl group) are prepared by (in either order) reducing the 3-oxo-group of a 2-methyl-3-oxo-tetrahydrofuran-(5)-carboxylic acid ester to a hydroxyl group and converting the esterified carboxyl group therein to a quaternized amino-methyl group while protecting the keto group (if present) by temporary ketalization, if desired. Preferred methods for converting the esterified carboxyl group to a quaternized amino methyl group are by (a) reacting the ester group with a dialkyl amine to form the dialkyl amide group, reducing this to the dialkylamino-methyl group and treating this with a quaternizing agent, and (b) reducing the ester group into a carbinol group, halogenating this to form a halogeno-methyl group and treating this with a tertiary amine. The keto group may be protected by ketalization with methyl ortho-formate when the esterified carboxylic group is being converted to a quaternized aminomethyl group. The products of p the invention may be resolved into their stereoisomeric forms by conventional means, e.g. fractional crystallization. 2 - Methyl - 3 - oxo - tetrahydrofuran - (5) - carboxylic acid methyl ester (a dinitrophenyl hydrazone is also described) is prepared by the addition of ethyl lactate to ethyl fumarate (or maleate), separating the copper salt of the product which, decomposed with dilute sulphuric acid, gives 2-methyl-3-oxo-4,5-di-(ethoxy-carbonyl)-tetrahydrofurn; the last-named compound on decarboxylation gives 2-methyl-3-oxo - tetrahydrofurn - (5) - carboxylic acid which is esterified. The dinitrophenylhydrazone of 2-methyl-3-oxo-5 - dimethylaminocarbonyl - tetrahydrofuran is also described.