GB712343A - Improvements relating to 1, 4-disubstituted piperazines - Google Patents

Abstract

The invention comprises piperazines of the general formula <FORM:0712343/IV (b)/1> where R is a hydrogen atom or an alkyl radical, R1 is an alkyl or aralkyl radical and R2, R3, R4 and R5 are hydrogen atoms or alkyl radicals, not more than one of R2 and R3 being an alkyl radical and not more than one of R4 and R5 being an alkyl radical. They are prepared by reacting an N-substituted piperazine of the formula <FORM:0712343/IV (b)/2> with an acyl halide of the formula <FORM:0712343/IV (b)/3> in which X is a halogen atom, or with the corresponding acid anhydride, when R is an alkyl radical, or with formic acid when R is a hydrogen atom. The reaction temperature is suitably between -10 DEG and 100 DEG C. The reaction may be carried out under anhydrous conditions in a solvent such as ether, alcohol or benzene, or when R is an alkyl radical may be carried out in an aqueous solvent in the presence of an alkaline substance as a hydrogen halide acceptor. In examples, there are prepared 1-carbethoxy - 4 - n - butyryl piperazine and the corresponding 4-diethylacetyl, 4-isocaproyl, 4-acetyl and 4-propionyl compounds; 1-carbobenzoxy-4-acetyl piperazine and the corresponding 4-propionyl, 4-n-butyryl and 4-formyl compounds; d,l-trans-1-carbethoxy-4-acetyl-2 : 5 - dimethylpiperazine; 1 - carbomethoxy-4-n-butyryl piperazine and 1-carbo-n-butoxy-4-n-butyryl piperazine.