PRODUCTION OF 2-AZABICYCLO(2.2.1)HEPT-5-EN-3-ONE

PROBLEM TO BE SOLVED: To economically and safely obtain 2-azabicyclo[2.2.1]hept-5-en-3-one useful as an intermediate for medicines such as antiviral agents in high purity and yield by ring addition reaction between a substituted sulfonyl cyanide and cyclopentadiene followed by subjecting the resultant reaction liquor to hydrolysis under a specific pH condition. SOLUTION: This compound is obtained by the following process: (A) a compound of the formula, R-SO2 CN [R is a 1-6C alkyl or (substituted) phenyl] and (B) cyclopentadiene are subjected to ring addition reaction in (C) an (aromatic) hydrocarbon solvent (e.g. pentane, heptane, benzene, xylene) e.g. at 5-30 deg.C to produce a solution of a compound Z of the formula, which is then added at e.g. 3-20 deg.C to (D) a mixed solvent composed of water and a water-soluble solvent (e.g. acetone, dioxane) while controlling the reaction system to pH 3-7 by making use of e.g. an alkali (alkaline earth) metal hydroxide, to effect hydrolysis of the compound Z.