Methyl iodide → HCID 178436318, compound

Participants

Reaction Conditions

Reaction Steps

A solution of 2.55 g of 1-ethynyl-4-(trans-4-pentylcyclohexyl)benzene (prepared according to Example 3) in 90 ml of absolute tetrahydrofuran was placed at -20° C. in a sulphonation flask under argon gasification and treated within 5 minutes with 11.0 ml of a 1.0N solution of butyl lithium in hexane. The clear yellow mixture was subsequently stirred at -20° C. for a further 30 minutes and then treated in sequence with 10 ml of hexamethylphosphoric acid triamide and 747 μl of methyl iodide. After warming to room temperature, the now dark violet mixture was stirred for a further 4 hours, subsequently poured into 150 ml of water and extracted three times with 150 ml of petroleum ether each time. The organic phases were washed twice with 200 ml of water each time, dried over magnesium sulphate and concentrated. Low-pressure chromatography (0.5 bar) of the residue (3.01 g) on silica gel with hexane gave in sequence 806 mg (31.7%) of 1-ethynyl-4-(trans-4-pentylcyclohexyl)benzene, 431 mg (16.3%) of a mixture of 1-ethynyl-4-(trans-4-pentylcyclohexyl)benzene and 1-(1-propynyl)-4-(trans-4-pentylcyclohexyl)benzene and 601 mg (22.4 %) of 1-(1-propynyl)-4-(trans-4-pentylcyclohexyl)benzene. A recrystallization of the last fraction from 50 ml of methanol yielded 464 mg of 1-(1-propynyl)-4-(trans-4-pentylcyclohexyl)benzene as colourless crystals; m.p. (C-N) 41.6° C., cl.p. (N-I) 64.9° C.; η(22° C.)=23 cp: η(45° C.)=7.7 cp.

Provenance & Evidence