1,1-Dimethylhydrazine → 4-benzyl-4-(N',N'-dimethylhydrazinocarbonyl)piperidine-1-carboxylic acid tert-butyl ester

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Reaction Steps

To a solution of 4-benzylpiperidine-1,4-dicarboxylic acid 1-tert-butyl ester (0.75 g, 2.35 mmol) (prepared as in Gilligan et al J. Med. Chem. 1994, 364-370) in methylene chloride (10 ml) was added 1-hydroxy-7-azabenzotriazole (0.32 mg, 2.35 mmol) and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (0.45 g, 2.35 mmol) and the mixture was stirred for 30 min. Then N′,N′-dimethylhydrazine (0.27 ml, 3.53 mmol) and diisopropylethylamine (0.52 ml, 3.06 mmol) was added and the mixture was stirred for 2 days. Methylene chloride (100 ml) was added and the mixture was washed with saturated aqueous sodium hydrogencarbonate (20 ml), water (20 ml), dried (MgSO4), filtered and concentrated in vacuo. The obtained oil was chromatographed on silica (40 g) with heptane/ethyl acetate (1:2) to give 0.76 g of 4-benzyl-4-(N′,N′-dimethylhydrazinocarbonyl)piperidine-1-carboxylic acid tert-butyl ester as a colorless oil.

Provenance & Evidence