ethyl 4-cyclohexyl-3-oxobutanoate

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

Procedure: Ethyl 4-cyclohexyl-3-oxobutyrate (0.84 g, 3.96 mmol, 1.25 eq.) obtained in Example 102a) and 4-azido-N-ethylbenzamide (0.60 g, 3.15 mmol) were dissolved in ethanol (20 ml), sodium ethoxide (298 mg, 3.96 mmol, 1.25 eq.) was added, and the mixture was stirred at room temperature for 30 min, and then at 50° C. for 14 hr. Water (20 ml) was added to the reaction mixture, ethanol was evaporated, and the residue was diluted with 2% aqueous sodium carbonate solution (20 ml) and washed with ethyl acetate-hexane (2:1, 50 ml). The organic layer was extracted with 2% aqueous sodium carbonate solution (20 ml). The aqueous layers were combined, acidified (pH<3) with 6N hydrochloric acid, and extracted with ethyl acetate-THF (4:1, 40 ml) and ethyl acetate (30 ml). The organic layers were combined, washed with saturated brine, dried over anhydrous sodium sulfate, and concentrated, and diethyl ether and ethyl acetate were added. The precipitate was collected by filtration, washed with diethyl ether and dried to give the title compound as a pale-yellow powder (1.04 g, 2.91 mmol, 92.4%). at 50° C. for 14 hr was evaporated the residue was diluted with 2% aqueous sodium carbonate solution (20 ml) washed with ethyl acetate-hexane (2:1, 50 ml) The organic layer was extracted with 2% aqueous sodium carbonate solution (20 ml) extracted with ethyl acetate-THF (4:1, 40 ml) and ethyl acetate (30 ml) washed with saturated brine dried over anhydrous sodium sulfate concentrated diethyl ether and ethyl acetate were added The precipitate was collected by filtration washed with diethyl ether dried