Process for producing and method of crystallizing 2-azabicyclo(2.2.1)hept-5-en-3-one

A process for producing 2-azabicycloÄ2.2.1Ühept-5-en-3-one by reacting a sulfonyl cyanide represented by the general formula R-SO2CN (in which R represents an alkyl group or a phenyl group which may have a substituent), in the presence of water and in a hydrocarbon solvent under a pH condition of from 4 to 7 inclusive. 2-AzabicycloÄ2.2.1Ühept-5-en-3-one can be produced in a high yield and a high purity in one step process, with a reduced amount of solvent used, safely and with good productivity. A method of crystallizing 2-azabicycloÄ2.2.1Ühept-5-en-3-one by dissolving 2-azabicycloÄ2.2.1Ühept-5-en-3-one into an organic solvent mainly comprising at least one of diisopropyl ether and methyl tertiary butyl ether, cooling the solution to deposit crystals of 2-azabicycloÄ2.2.1Ühept-5-en-3-one. Finely particulate crystals of 2-azabicycloÄ2.2.1Ühept-5-en-3-one excellent in fluidity and handlability can be obtained with a simple procedure and in a high recovery rate.