GB743221A - Improvements in or relating to the manufacture of acrylonitriles - Google Patents

Abstract

Acrylonitriles of the formula <FORM:0743221/IV(a)/1> (in which R is hydrogen or an alkyl group having from 1 to 4 carbon atoms, W and Z are either both hydrogen or halogen atoms or one is a halogen atom and the other is hydrogen, and R11 is an alkyl group having from 1 to 4 carbon atoms) are made by reacting an acrylacetonitrile of the formula <FORM:0743221/IV(a)/2> with an orthoester of the formula <FORM:0743221/IV(a)/3> The reaction is preferably carried out by heating under reflux. For obtaining a high rate of reaction, the orthoester may be added in small portions at intervals to the heated arylacetonitrile. During the reaction an alcohol R11OH is formed and distilled off continuously. At the end of the reaction, the acrylonitrile may be crystallized from the reaction liquid, or unchanged aryl acetonitrile may be distilled fractinally under reduced pressure. The acrylonitrile obtained may be converted into a 2 : 4-diamino-pyrimidine by reaction with guanidine. In an example p-chlorophenylacetonitrile and ethyl orthopropionate are heated together under reflux and the ethyl alcohol formed during the reaction is removed through a short fractionating column. Small additional quantities of ethyl orthopropionate are added at intervals and the temperature is not allowed to exceed 185 DEG C. After 87 hours the reaction liquid is distilled fractionally under reduced pressure to give unchanged p-chlorophenyl-acetonitrile and a - p - chlorophenyl - b - ethoxy - b - ethylacrylonitrile. This acrylonitrile is heated with a solution of guanidine (prepared from the hydrochloride and ethanolic sodium ethoxide) under reflux for 18 hours to produce 2 : 4-diamino-5-p-chlorophenyl-6-ethyl pyrimidine. In other examples, p-chlorophenyl-acetonitrile and ethyl orthoacetate are heated together under reflux to form a - p - chlorophenyl - b - ethoxy - b -methylacrylonitrile which is subsequently refluxed with alcoholic guanidine to form 2:4-diamino - 5 - p - chlorophenyl - 6 - methylpyrimidine; 3 : 4-dichlorophenylacetonitrile and ethyl orthopropionate are heated together to form a - (3:4 - dichlorophenyl) - p - ethoxy - p-ethylacrylonitrile and to the reaction liquid guanidine in ethanolic sodium ethoxide is added, the mixture being then heated under reflux to form 2:4 - diamino - 5 - (31:41 - dichlorophenyl) - 6 - ethylpyrimidine; p. chlorophenylacetonitrile and isobutyl orthopropionate are reacted together to form a -p-chlorophenyl-p - isobutoxy - p - ethylacrylonitrile which is subsequently converted by reaction with guanidine into 2:4 - diamino - 5 - p - chlorophenyl-6-ethylpyrimidine. Phenylacetonitrile is heated with ethyl orthopropionate to form a -phenyl-b -ethoxy - b - ethylacrylonitrile which is subsequently heated with alcoholic guanidine to give 2:4 - diamino - 5 - phenyl - 6 - ethylpyrimidine. Other examples describe the production of a -p-chlorophenyl - b - methoxy - b - n - butylacrylonitrile, a - p - chlorophenyl - b - methoxy - b -ethylacrylonitrile, a - p - chlorophenyl - b -isobutoxy - b - n - butylacrylonitrile, a - p-chlorophenyl - b - ethoxy - b - n propylacrylonitrile, and a - p - chlorophenyl - b - ethoxy - b -n - amylacrylonitrile, and the corresponding 2:4-diamino-pyrimidines.