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1-ethoxy-2,3-difluoro-4-(4-propylenecyclohexyl)benzene[ No CAS ]
[ 174350-08-4 ]
Yield
Reaction Conditions
Operation in experiment
92%
With 5%-palladium/activated carbon; hydrogen In ethanol at 50℃;
3
A 1 L hydrogenation reactor was charged with 45.7 g (0.163 mol) of 1-ethoxy-2,3-difluoro-4- (4-propylenecyclohexyl) benzene, 300 ml of ethanol and 3 g of 5% palladium carbon. At hydrogen pressure of 0.3 ~ 0.5MPa, Hydrogenation at a temperature of 50 ° C until hydrogen uptake ends, GC detection of the product was inverse ratio of 3:97. The reaction solution was filtered to remove the catalyst, Concentrate the ethanol and recrystallize, and then vacuum distillation to give 1-ethoxy-2,3-difluoro-4- (Trans-4-propylcyclohexyl) benzene 42.3 g (0.15 mol), The yield of this step was 92%, the GC detection purity was 99.9%, and the cis-inverse ratio was 0.2: 99.8. Total yield was 75% with 1,4-cyclohexanedione monoethylene ketal.
cis-1-(4-propyl)cyclohexyl-2,3-difluoro-4-ethoxybenzene[ No CAS ]
[ 174350-08-4 ]
Yield
Reaction Conditions
Operation in experiment
88%
In diethyl ether at 25℃; for 3h; UV-irradiation;
1 Example 1 1-(4-propyl)cyclohexyl-2,3-difluoro-4-ethoxybenzene
The transposition method of the cis isomer is as follows: Add 400ml of petroleum ether and 100g of cis-isomer into a 1000ml three-necked bottle, stir to dissolve, control the temperature to about 25°C and use a low pressure mercury lamp (254nm) to irradiate the reaction for 3 hours, After the completion of the reaction, the reaction solution was sampled and analyzed, and 97 mol% of trans isomer (GC retention time 11.1 min) and cis isomer 0.6 mol% (GC retention time 10.3 min) were obtained. Add 50ml of water to the above-mentioned reaction solution, layer by layer, when the organic layer is concentrated to almost no solvent, then crystallize three times with 200ml of ethanol; crystallize once with 100ml of ethanol and 10ml of petroleum ether, 99.9 mol% of the trans isomer was obtained, and the yield was 88%. After the mother liquor was collected, the trans isomer could be obtained by transposition again.