N,N-diethylpiperazine-1-carboxamide

Conditions: temp:100.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 2.14 g of 3-chloromethyl-5-(3-fluoro-4-phenyl-α-methylbenzyl)-1,2,4-oxadiazole, 2.54 g of N,N-diethyl-1-piperazine carboxamide and 15 ml of dry DMF was heated at 100° C. for 2 hours. After cooling, the reaction mixture was poured into ice-water and extracted with diethyl ether. The organic phase was washed with water, dried over magnesium sulfate and evaporated. The residue was chromatographed over silica gel using chloroform-methanol (50:1, v/v) to yield 2.43 g of 3-[4-(N,N-diethylcarbamoyl)piperazinomethyl]-5-(3-fluoro-4-phenyl-α-methylbenzyl)-1,2,4-oxadiazole as a light brown oil. To a solution of this product in ethanol was added equal mole of ethanolic hydrogen chloride and the mixture was concentrated to dryness under reduced pressure. Recrystallization of the residue from ethanol-diethyl ether gave colorless crystals, m.p. 181°-182° C. After cooling extracted with diethyl ether The organic phase was washed with water dried over magnesium sulfate evaporated The residue was chromatographed over silica gel