PROCESS FOR PREPARING (1-CYANOCYCLOHEXYL) MALONIC ACID DIALKYL ESTER Russian patent published in 1994 - IPC

FIELD: synthesis of habapentine. SUBSTANCE: an improved process for preparing (1-cyanocyclohexyl) malonic acid dialkyl esters of the formula: wherein R is C₁-C₄ alkyl. Reagent 1: cyclohexylidene cyanalkylate of the formula: . Reagent 11: an alkali metal cyanide in an amount of 1-5 molar equiv. per reagent 1. Conditions: boiling in an alcohol. reagent 11: a prussic acid in an amount of 1-20 molar equiv. per reagent 1. Conditions: a catalytic amount of an alkali metal cyanide in an amount of 0.1-50 mole % per reagent 1, a temperature of 20-150 C and a pressure established att he given temperature to obtain the corresponding alkylate of ( 1-cyanocyclohexyl )cyanoacetic acid of the formula 111: which compound is treated with an acid in an amount of 1-100 molar equiv. per the compound 111 in a lower C₁-C₄ aliphatic alcohol at a temperature of -20 C to -50 C and a pressure of 1-10 atm. EFFECT: simplified process for preparing habapentine by reducing the number of stages. 3 tbl