反应详情

Diphenylphosphoryl azide (1.81 mL, 8.38 mmol) was added to a mixture of the 9-methoxy-1,3-dioxo-1,2,3,6-tetrahydropyrrolo[3,4-c]carbazole-4-carboxylic acid (2.55 g, 8.22 mmol), prepared as in example 4, and Et3N (1.17 mL, 8.38 mmol) in anhydrous t-butanol (300 mL) and the mixture was refluxed under an atmosphere of nitrogen for 16 h. The solution was concentrated in vacuo and the residue partitioned between EtOAc and saturated aqueous NaHCO3. Insoluble material was removed by filtration of the two layers through Celite, washing through with more EtOAc. The organic phase was dried, the drying agent was removed and the solution was concentrated to dryness and gave a yellow solid. This material was dissolved in CH2Cl2/trifluoroacetic acid (1:1) (200 mL) and the solution was held at room temperature for 1 h. After concentration in vacuo the residue was partitioned between EtOAc and saturated aqueous NaHCO3 solution. The EtOAc solution was dried, the drying agent was removed and the solution was concentrated to dryness to give an orange solid which was adsorbed onto silica and chromatographed. Elution with ethyl acetate/petroleum ether (1:1) followed by ethyl acetate and then methanol/ethyl acetate (1:9) gave 4-amino-9-methoxypyrrolo[3,4-c]carbazole-1,3(2H,6H)-dione (6) as an orange powder (2.16 g, 93%), mp 342–345° C. 1H NMR δ [(CD3)2SO] 11.18 (s, 1H), 10.78 (br s, 1H), 8.18 (d, J=2.5 Hz, 1H), 7.29 (d, J=8.7 Hz, 1H), 7.01 (dd, J=8.7, 2.5 Hz, 1H), 6.83 (s, 1H), 6.28 (br s, 2H), 3.82 (s, 3H). Found: C, 63.05; H, 3.99; N, 14.05. C15H11N3O3, 1/2H2O requires C, 63.04; H, 4.06; N, 14.7.

1. temperaturethe mixture was refluxed under an atmosphere of nitrogen for 16 h
2. concentrationThe solution was concentrated in vacuo
3. customthe residue partitioned between EtOAc and saturated aqueous NaHCO3
4. customInsoluble material was removed by filtration of the two layers through Celite
5. washwashing through with more EtOAc
6. customThe organic phase was dried
7. customthe drying agent was removed
8. concentrationthe solution was concentrated to dryness
9. customgave a yellow solid
10. concentrationAfter concentration in vacuo the residue
11. customwas partitioned between EtOAc and saturated aqueous NaHCO3 solution
12. dry with materialThe EtOAc solution was dried
13. customthe drying agent was removed
14. concentrationthe solution was concentrated to dryness
15. customto give an orange solid which
16. customchromatographed
17. washElution with ethyl acetate/petroleum ether (1:1)