Pivaloyl chloride → Ethyl 5-(2,2-dimethylpropanoyl)-3-[(4-fluorobenzoyl)amino]-6,6-dimethyl-5,6-dihydropyrrolo[3,4-c]pyrazole-1(4H)-carboxylate

Participants

Reaction Steps

Ethyl 3-[(4-fluorobenzoyl)amino]-6,6-dimethyl-5,6-dihydropyrrolo[3,4-c]pyrazole-1(4H)-carboxylate hydrochloride (2.0 g, 5.77 mmol) in dichloromethane (70 ml) was treated, at 0° C., with N,N-diisopropylethylamine (1.6 ml, 9.2 mmol, 1.6 eq) and with pivaloyl chloride (780 μL, 6.3 mmol, 1.1 eq). Gradually, the reaction was brought to room temperature and stirred overnight (TLC: CH2Cl2/EtOAc 90/10). The solution was washed with saturated sodium hydrogencarbonate aqueous solution and brine. The organic phase was dried over sodium sulfate, evaporated and purified by flash chromatography (eluent: CH2Cl2/EtOAc 90/10) to afford 2.03 g of the title compound in 82% yield.

Provenance & Evidence