Ammonia → 2,4-Dioxo-3-azaspiro(5.5)undecane-1,5-dicarbonitrile

Participants

Reaction Conditions

Reaction Steps

98 g (1 mol) of cyclohexanone, 226 g (2 mol) of ethyl cyanoacetate, and 392 g of 96% methanol were mixed in a reaction flask, to which 272 g of aqueous ammonia (equivalent to 4 mol of ammonia gas) was added under stirring. Specifically, to carry out the addition of aqueous ammonia, the temperature was lowered to within the range of −5° C. to 0° C., ¾ of the prescribed amount of aqueous ammonia was added dropwise, the reaction mixture was then stirred for a first 12 hours with the temperature maintained at −5° C. to 0° C., and a second 12 hours with the temperature maintained at 5 to 10° C., and then the rest ¼ of aqueous ammonia was added. The reaction mixture was heated to and maintained at 20° C. to 25° C. for 24 hours under stirring. The mixture was then heated to 60° C., to which water was added in an amount equivalent to methanol, that is, 980 g water was added. The pH value was adjusted to 2-3 with dropwise addition of sulfuric acid, after which the temperature was lowered to below 5° C. and the mixture was centrifugally filtered. The filter cake was washed with water to pH 6-7, filtered, and dried to provide 1,5-dicyano-2,4-dioxo-3-azaspiro[5,5]-undecane. Yield: 85%, melting point: 202-210° C.

Provenance & Evidence