反応 #93451

反応方程式

iodine

hydrochloric acid

magnesium

trans-1-(bromomethyl)-4-pentylcyclohexane

4,4'-bis(bromomethyl)biphenyl

→

4,4'-bis[2-(trans-4-pentylcyclohexyl)ethyl]biphenyl

収率 22.0%

4-(bromomethyl)-4'-[2-(trans-4-pentylcyclohexyl)ethyl]biphenyl

収率 9.0%

溶媒

tetrahydrofuran

tetrahydrofuran

tetrahydrofuran

tetrahydrofuran

反応条件

後処理

1. 1
   workup.ADDITIONAfter completion of the addition
2. 2
   温度the mixture was heated
3. 3
   温度to reflux for another 30 minutes
4. 4
   workup.WAITThe yellow colouration which appeared initially disappeared after a few minutes
5. 5
   温度The mixture, warmed to -15° C.
6. 6
   抽出extracted three times with 50 ml of diethyl ether each time
7. 7
   洗浄The organic phases were washed with 50 ml of saturated sodium chloride solution
8. 8
   乾燥dried over magnesium sulphate
9. 9
   濃縮concentrated

実験手順

122 mg of magnesium shavings were covered with 3 ml of absolute tetrahydrofuran in a sulphonation flask under argon gasification, and, after the addition of a crystal of iodine, treated with a solution of 1.24 g of trans-1-(bromomethyl)-4-pentylcyclohexane in 7 ml of absolute tetrahydrofuran. After completion of the addition, the mixture was heated to reflux for another 30 minutes and then the mixture, cooled to -78° C., was treated with 0.7 ml of a 0.1N solution of dilithium tetrachlorocuprate in tetrahydrofuran and subsequently with a solution of 670 mg of 4,4'-bis(bromomethyl)biphenyl in 10 ml of absolute tetrahydrofuran. The yellow colouration which appeared initially disappeared after a few minutes. The mixture, warmed to -15° C., was subsequently stirred for a further 17 hours, then treated with 25 ml of 2N hydrochloric acid and extracted three times with 50 ml of diethyl ether each time. The organic phases were washed with 50 ml of saturated sodium chloride solution, dried over magnesium sulphate and concentrated. Low-pressure chromatography (0.5 bar) of the residue (1.06 g) on silica gel with hexane and subsequently with hexane/diethyl ether (19:1) as the eluent gave in sequence 1,1'-ethylene-bis(trans-4-pentylcyclohexane), 228 mg (22%) of 4,4'-bis[2-(trans-4-pentylcyclohexyl)ethyl]biphenyl, 78 mg (9 %) of 4-(bromomethyl)-4'-[2-(trans-4-pentylcyclohexyl)ethyl]biphenyl as well as 4,4'-bis(bromomethyl)biphenyl. A single crystallization of the 228 mg of 4,4'-bis[2-(trans-4-pentylcyclohexyl)ethyl]biphenyl from hexane yielded 194 mg of colourless needles having a clearing point above 300° C. (further phase transitions at 68° C., 84° C., 161° C., 203° C., 221° C. and 224° C.). Rf-values (hexane): 4,4'-bis(bromomethyl)biphenyl 0.14; 4-(bromomethyl)-4'-[2-(trans-4-pentylcyclohexyl)ethyl]biphenyl 0.24; 4,4'-bis[2-(trans-4-pentylcyclohexyl)ethyl]biphenyl 0.40.

出典