Dimethylformamide → HCID 87939624, compound

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Reaction Steps

Compound 35a (3.45 g, 8.96 mmol) obtained in Example 35 was dissolved in tetrahydrofuran (100 mL), to the solution was added a 1.50 mol/L solution (9.0 mL) of lithium diisopropylamide (13.5 mmol, 1.5 equivalents) in cyclohexane at −78° C., and the mixture was stirred for 1 hour. To the reaction solution was added a solution (10 mL) of N,N-dimethylformamide (2.83 g, 38.7 mmol, 4.3 equivalents) in tetrahydrofuran, and the mixture was stirred at −78° C. for 1 hour, then warmed to room temperature and stirred for 1 hour. To the reaction solution was added saturated aqueous ammonium chloride and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride and dried over anhydrous sodium sulfate, and the solvent was evaporated. The residue was purified by silica gel column chromatography (ethyl acetate:n-hexane=33:67 to 50:50). To the residue was added ethyl acetate, and the deposited crystals were collected by filtration to obtain the title compound (3.31 g, 89%) as white crystals.

Provenance & Evidence