The invention discloses a preparation method of 2-azabicyclo(2.2.1)hept-5-
alkene-3-
ketone, which is an intermediate for the synthesis of antiviral
medicine carbonyl ring
nucleoside, which is characterized in that, an
aqueous solution prepared by
anhydrous sodium sulfite and
sodium bicarbonate is added to a reactor; the temperature is controlled between 0 to 60 DEG C; a fixed amount of
methanesulfonyl chloride is added by dropping, and the temperature is maintained to react for 2 to 4 hours to prepare methyl
sulfonate solution; a fixed amount of
ether solvent is added to the solution, and under a temperature
ranging from 10 to 60 DEG C, cyanogens
chloride is added; after 4 to 6 hours reaction, cyclopentadienyl is added by dropping; the pH value of the reaction solution is controlled between 1.5 to 3 to react for 3 to 5 hours; then
sodium hydroxide is used for regulating the pH value to 7 to 9; after standing, the
ether solvent is separated, and a fixed amount of methyl
chloride is used for separated extraction 2-azabicyclo(2.2.1)hept-5-
alkene-3-
ketone; the methyl
chloride is distilled and a crude product is obtained; the crude product is decolorized by
activated carbon and recrystallized in
ether solvent; 2-azabicyclo(2.2.1)hept-5-
alkene-3-
ketone with a purity of more than 99.6 percent is obtained after
drying. The preparation method has the advantages of rich
raw material sources, low cost, simple technological process, small emission of three wastes, benefits for industrial production and other advantages.