Nitrite → 5-Cyano-4,5-dihydro-3H-pyrazole-3,4-dicarboxylic acid diethyl ester

Participants

Reaction Conditions

Reaction Steps

To a one liter round bottom flask containing a cold (0° C.) slurry of 67.6 g (0.6756 mol) of aminoacetonitrile hydrochloride and 44.2 ml (0.2702 mol) of diethyl fumarate in 300 ml of ethyl acetate, were added dropwise, over one hour, an aqueous solution of 46.6 g (0.6756 mol) of sodium nitrite dissolved in 90 ml of water. The temperature of the reaction mixture was maintained at about 0° C. during the nitrite addition, then warmed to room temperature (24° C.) where the mixture was stirred for about 3 hours. The organic layer was separated from the aqueous layer and then stirred at room temperature overnight to provide a solution of 5-cyano-4,5-dihydro-3H-pyrazole-3,4-dicarboxylic acid diethyl ester dissolved in ethyl acetate.

Provenance & Evidence