Action 1: Synthesis of 1-isopropylcyclopentadiene
Under nitrogen protection, liquify metallic salt (14 g, 0.6 mol) in tetrahydrofuran (250 g), consist of cyclopentadiene (48 g, 0.72 mol), react at 30 ° C for 1 hour, and vaporize the tetrahydrofuran under lowered stress. Dimethyl sulfoxide (50 g) was consisted of in acquire an alternative of salt cyclopentadienyl in dimethyl sulfoxide. Include n-hexane (142 g) to this choice, incredible to 0 ° C, and include isopropyl bromide (148 g, 1.2 mol) dropwise within 50 mins. Keep the temperature at no more than 5 ° C throughout the enhancement, and no greater than 10 ° C after the enhancement; After that gradually add 1 N hydrochloric acid solution (62 g) and n-hexane (155 g), mix at 10 ° C for 5 minutes, and allow stand for 5 minutes. The natural layer and the liquid layer are separated to obtain isopropylcyclopentadiene-containing Service (420 g), the alternative was enabled to stand for 6 h at 20.0 ° C for isomerization. The proportion of isomers happened establishing 1: positioning 5: position 2 = 96.3: 1.7: 2.0, and the return was 95.2%.
Step 2: Synthesis of 7,7-dichloro-3-isopropyl-bicyclo [3,2,0] hept-2-en-6-one
Liquify isopropylcyclopentadiene (61.77 g, 0.571 mol) in n-hexane (500 mL), gradually include dichloroacetyl chloride (92.58 g, 0.658 mol) at 0 ° C, and later on add it at 0 ° C. Triethylamine (66.58 g, 0.658 mol) was added dropwise within 2 hours, after that 1 N hydrochloric acid was added to liquify the salt produced by the response, and the natural layer was divided to obtain the enone-containing adduct 7,7-dichloro-3- The n-hexane solution of isopropyl-bicyclo [3,2,0] hept-2-en-6-one was evaporated to do away with the solvent and later on distilled under lessened pressure to acquire 107 g of a fraction having ketene adduct, with a return of 85.8%., pureness 98%. The proportion of isomers examined by GC is first placement: 5th positioning: second positioning = 99.8:0:0.2.
Action 3: Synthesis of hinokitol
Liquify the ketene adduct (173.76 g, 0.761 mol) in a consolidated solvent of tert-butyl alcohol (1032 g), water (274 g) and acetic acid (274 g), and warm to reflux. Triethylamine (539.04 g, 5.327 mol) was included dropwise under reflux. The dropwise addition was completed in 2.5 h. After continuing to be to reflux for 1.5 h, it was cooled to space temperature level. Consist of water (1575 g), focused hydrochloric acid (119 g) and n-hexane (1000 mL) subsequently, and split the layers. The solvent was vaporized from the organic layer under lowered stress to get 130.09 g of unrefined hinokitiol (pureness 79.9%), with a return of 83.2%. The unrefined product was distilled under lowered pressure, and after distilling off the previous fraction at 45-90 ° C/1 mm Hg, the main portion at concerning 95 ° C/1 mm Hg was accumulated to obtain 106.64 g of hinokinol, with a purification recuperation rate of 97.5%. Liquify this section in n-hexane (500 mL) at 40 ° C and cool to 0 ° C at a rate of 1 to 2 ° C per minutes. The crystals were precipitated and filtered with suction. The filter cake was cleaned up with n-hexane cooled to 0 ° C and dried out to get 93.27 g (0.568 mol) hinokinol crystals with a pureness of 99.9% and a crystallization recovery rate of 92.1%.
