Reaction #334856
ord-894b4502453c4d80ab50e89cda2790c7
Reaction equation
Reagents
Solvents
Conditions
Workup
- 1Extractionextracted three times with 100 ml of petroleum ether each time
- 2WashThe organic phases were washed twice with 100 ml of water each time
- 3Dryingdried over magnesium sulphate
- 4Concentrationconcentrated
Procedure
A solution of 1.98 g of p-[trans-4-(2,3-dibromopentyl)cyclohexyl]benzonitrile (erythro/threo 66.6:32.8) in 30 ml of glacial acetic acid was treated at room temperature with 2.0 g of zinc powder while gassing with argon and the suspension was stirred at room temperature for 1 hour. The reaction mixture was subsequently poured into 100 ml of water and extracted three times with 100 ml of petroleum ether each time. The organic phases were washed twice with 100 ml of water each time, dried over magnesium sulphate and concentrated. Low-pressure chromatography (0.5 bar) of the yellowish residue (1.16 g) on silver nitrate-coated silica gel with hexane/diethyl ether (vol. 90:10) gave 586 mg (48%) of p-[trans-4-(2E-pentenyl)cyclohexyl]benzonitrile and 171 mg (14%) of p-[trans-4-(2Z-pentenyl)cyclohexyl]benzonitrile as colourless oils. The 2E-isomer has a melting point of 9.6° C. and 16.1° C. (2 modifications) and a virtual clearing point of -67° C.; the 2Z-isomer has a melting point of -7.7° C. and a virtual clearing point of -54° C.