Ammonia → 1-(2,2-Dimethylpropanoyl)-4-(1,1-dimethylprop-2-yn-1-yl)piperazine

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Reaction Steps

0.756 g (6 mmol) of 1,1-dimethylprop-2-yn-1-yl acetate (J. Org. Chem. 1994, 59, 2282-4) and 2.235 g (12 mmol) of 1,1-dimethylethyl piperazine-1-carboxylate are dissolved in 9 ml of tetrahydrofuran and then 0.059 g (0.6 mmol) of cuprous chloride is added. The mixture is heated at reflux for 3 hours. After cooling to ambient temperature, 100 ml of ethyl acetate, 10 ml of 1N aqueous sodium hydroxide and 2 ml of 30% ammonia are added. The organic phase is separated off and washed with 2 times 10 ml of water and then with 10 ml of saturated aqueous sodium chloride solution. It is dried over sodium sulphate and evaporated. The product is purified by chromatography on silica gel, eluting with an 85/15 then 75/25 and 65/35 mixture of cyclohexane and ethyl acetate, to give 1.19 g (4.71 mmol) of product in the form of a pale yellow solid.

Provenance & Evidence