1-Methylpiperazine → HCID 178481079, compound

Participants

Reaction Steps

To a solution of triphosgene (195 mg, 0.65 mmol, 0.56 eq) in DCM (15 ml) was added a solution of ethyl 3-[(4-fluorobenzoyl)amino]-6,6-dimethyl-5,6-dihydropyrrolo[3,4-c]pyrazole-2(4H)-carboxylate hydrochloride (442 mg, 1.15 mmol) in DCM (30 ml) followed by N,N-diisopropylethylamine (760 μl, 4.31 mmol, 3.75 eq). After 3 hours, a solution of N-methylpiperazine (195 μl, 1.72 mmol, 1.5 eq) and diisopropylethylamine (300 μl, 1.72 mmol, 1.5 eq) in DCM (8 ml) was added. The reaction was stirred overnight at room temperature (TLC: CH2Cl2/MeOH 90/10). The solution was washed with brine, the organic phase was dried over sodium sulfate and concentrated. The residue was dissolved in methanol (16 ml), treated with TEA (1.6 ml, 11.5 mmol, 10 eq) and stirred overnight at room temperature. (TLC: CH2Cl2/MeOH 90/10). After evaporation, the solid was purified by flash chromatography (eluent: CH2Cl2/MeOH 90/10). The solid was treated with diisopropylether and filtered to afford 0.294 g of the title compound in 64% yield.

Provenance & Evidence