反应详情

To a solution of triphosgene (550 mg, 1.85 mmol, 0.4 eq) in tetrahydrofuran (50 ml) was added, at −40° C., a solution of 5-tert-butyl 1-ethyl 3-amino-6,6-dimethyl-4,6-dihydropyrrolo[3,4-c]pyrazole-1,5-dicarboxylate (1.5 g, 4.62 mmol) in tetrahydrofuran (50 ml) and N,N-diisopropylethylamine (1.8 ml, 2.2 eq). After 3 hours, a solution of piperidine (690 μl, 1.5 eq) and N,N-diisopropylethylamine (1.2 ml, 1.5 eq) in tetrahydrofuran (25 ml) was added. The reaction was allowed to reach room temperature in 2 hours (TLC: EtOAc/hexane 90/10). After evaporation of the solvent the solid was dissolved in DCM and the solution was washed with brine, the organic phase was dried over sodium sulfate and concentrated. The solid was purified by flash chromatography (eluent: EtOAc/hexane 50/50). The solid was treated with diisopropylether and filtered to afford 1.45 g of the title compound in 72% yield.

1. waitto reach room temperature in 2 hours
2. customAfter evaporation of the solvent the solid
3. dissolutionwas dissolved in DCM
4. washthe solution was washed with brine
5. dry with materialthe organic phase was dried over sodium sulfate
6. concentrationconcentrated
7. customThe solid was purified by flash chromatography (eluent: EtOAc/hexane 50/50)
8. additionThe solid was treated with diisopropylether
9. filtrationfiltered