Ethyl cyanoacetate → Ethyl 1-cyano-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylate

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Reaction Steps

A mixture of ethyl cyanoacetate (12.44 parts), 1,1,3,4-tetrachloro-4-methylpent-1-ene (11.1 parts), 1,1-dichloro-4-methylpenta-1,3-diene (7.55 parts), cupric acetate H2O (2.0 parts) and in two cases lithium halide, in acetonitrile (100 parts by volume) is heated to reflux and held at 75°-80° C. for 6 hours. After cooling to room temperature the suspension is filtered and the residue is washed twice with acetonitrile (20 parts by volume). The combined filtrate and washes are distilled under reduced pressure to remove acetonitrile and the residue is extracted with a mixture of toluene (100 parts by volume), water (150 parts by volume) and concentrated hydrochloric acid (100 parts by volume). After filtering from extraneous matter the filtrates are separated and the toluene layer is washed twice with hydrochloric acid (50 parts by volume) diluted with water (50 parts) and finally four times with water (50 parts). The toluene is removed by distillation under reduced pressure to yield crude ethyl 1-cyano-3-(2',2'-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylate. Details are given in the following table:

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