Sodium hydride → 1-Acetyl-4-ethynyl-4-(2-nitrophenoxy)piperidine

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Reaction Steps

To a stirred solution of dimsyl sodium, prepared from 16.5 g of sodium hydride (50% in oil, washed three times with hexanes) and 400 ml of dimethylsulfoxide at 17°-25° was added, in aliquots, 57.7 g of 1-acetyl-4-ethynyl-4-piperidinol. Upon completion of the addition, 55.3 g of 2-fluoronitrobenzene was added dropwise at a rate such that the temperature remained below 25°. The mixture was stirred at room temperature for 20 min, poured into cold water, extracted three times with ether, washed with saturated sodium chloride solution and dried over anhydrous potassium carbonate. Filtration followed by evaporation of solvent provided an oil, which crystallized on standing. Recrystallization from ethyl acetate/cyclohexane provided 23.6 g (24%) of product, mp 112°-115°.

Provenance & Evidence