Diisopropylamine → p-(5-Pentyl-2-pyrimidinyl)phenylpropiolonitrile

Participants

Reaction Conditions

Reaction Steps

A solution of 355 mg of 2-(p-ethynylphenyl)-5-pentylpyrimidine (prepared according to Example 8) in 30 ml of absolute tetrahydrofuran was placed at -78° C. in a sulphonation flask under argon gasification and treated within 15 minutes with a solution, cooled to about 0° C., of 152 mg of lithium diisopropylamide (prepared by adding 0.89 ml of a 1.60N solution of butyl lithium in hexane to a solution of 0.22 ml of diisopropylamine in 10 ml of absolute tetrahydrofuran at 0° C.) in 10 ml of absolute tetrahydrofuran. After 5 minutes, 182 μl of phenyl cyanate were added, the mixture was stirred at -78° C. for 90 minutes, then poured into 30 ml of water 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 (0.4 bar) of the residue on silica gel with 5% ethyl acetate/petroleum ether gave 88 mg (22%) of p-(5-pentyl-2-pyrimidinyl)phenylpropiolonitrile as colourless crystals. Recrystallization from methanol yielded colourless needles (purity 99.4%); m.p. (C-N) 76.2° C., cl.p. (N-I) 128.5° C.

Provenance & Evidence