GB833820A - Improvements in or relating to the preparation of pyrrolidyl esters and quaternary compounds thereof - Google Patents

Abstract

Compounds of formula <FORM:0833820/IV (b)/1> wherein Ph represents phenyl and R is C1-4 alkyl or allyl, are prepared by reacting a 1-alkyl-2-hydroxymethylpyrrolidine of formula <FORM:0833820/IV (b)/2> with an acid halide of formula <FORM:0833820/IV (b)/3> where X is chlorine or bromine, to give a compound of formula <FORM:0833820/IV (b)/4> which is then converted to the product (I) by treatment with water and a base. The compounds (I) in which R is C2-4 alkyl or allyl and salts thereof are claimed per se. The treatments with water and the base may be simultaneous or successive. The first stage of the reaction may be effected in a solvent, e.g. butanone. The products (I) may be reacted with an ester R1Z to form a quaternary salt of formula <FORM:0833820/IV (b)/5> where R1 is alkyl or aralkyl and Z is a halogen, alkyl sulphate or aryl sulphonate radical. The anion Z may be exchanged for other anions, e.g. by reaction with the silver salt of an appropriate inorganic or organic acid. Optically active products may be resolved into their isomers. Starting materials prepared are 1-methyl-2-hydroxymethylpyrrolidine by the formaldehyde/formic acid methylation of 2-hydroxymethylpyrrolidone obtained by LiAlH4 reduction of butyl pyroglutamate; 1-ethyl-, 1-n-propyl- and 1 - n - butyl - 2 - hydroxymethylpyrrolidine by the LiAlH4 reduction of (1-acetyl-2-pyrrolidyl)-methyl acetate, 1-n-propionyl-2-pyrrolidyl)-methyl propionate and (1-butyryl-2-pyrrolidyl)-methyl butyrate respectively, these being obtained by the action of acetic, propionic or butyric anhydride on 2-hydroxymethylpyrrolidine; 1-isopropyl and 1 - allyl - 2 - hydroxymethylpyrrolidine by the LiAlH4 reduction of butyl 1-isopropyl- and 1-allyl-pyroglutamate respectively, these being obtained by the action of isopropyl iodide or allyl bromide on the potassium derivative of butyl pyroglutamate. The Provisional Specification refers to compounds corresponding to I, III and IV, in which one phenyl group is replaced by cyclohexyl. Specification 820,503 is referred to.