Triethylamine → HCID 70358150, compound

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Reaction Steps

2.1 g (10 mmol) of 3-(5-methoxybenzocyclobuten-1-ylidene)propionic acid and 1.4 ml (10 mmol) of triethylamine are introduced under argon into 20 ml of toluene. 2.2 ml (10 mmol) of diphenylphosphorylazide are added thereto and the whole is heated, while stirring, at 80° for 30 minutes. The mixture is allowed to cool to room temperature, 2.9 ml (20 mmol) of 2-trimethyl- silylethanol are added thereto and the whole is heated at 80° for 7 hours. The reaction mixture is then concentrated to dryness in a rotary evaporator. The oily residue is taken up in diethyl ether, washed with water and 2N sodium hydroxide solution, dried over sodium sulphate and concentrated by evaporation. The crude product is purified by chromatography on a silica gel column, stirred at 50° for 2 hours with 10 ml (10 mmol) of a 1 molar solution of tetrabutylammonium fluoride in tetrahydrofuran and then concentrated to dryness by evaporation. The residue is stirred vigorously with n-pentane/water (1:1). The n-pentane phase is separated off and discarded. The aqueous phase is adjusted to pH 8 with ammonium chloride, whereupon a crystalline product precipitates. The latter is filtered off with suction. The mother liquor is saturated with sodium chloride, whereupon more product crystallises out. The crystallisates are combined, taken up in trichloromethane/methanol (1:1), dried over sodium sulphate and concentrated by evaporation. The crystalline residue is stirred with diethyl ether and then filtered. 2-(5-methoxybenzocyclobuten-1-ylidene)ethylamine of m.p. 238°-240° is obtained.

Provenance & Evidence