反应详情

A solution of sodium nitrite (4.62 g) in water (40 mL) was added dropwise over a period of 15 minutes at 0° C. to a solution of 5-amino-3-methyl-3H-benzooxazol-2-one (10 g) in acetic acid (400 mL). Stirring was continued for 10 minutes at 0° C. A solution of potassium iodide (11.12 g) in water (40 mL) was added dropwise over a period of 15 minutes. Stirring was continued for 1 hour at 0° C. Sodium pyrosulfite (1.0 g) was added to the reaction mixture. Stirring was continued for 10 minutes. The reaction mixture was then evaporated to dryness. The residue was dissolved in CH2Cl2 and the solution was poured into sat. Na2CO3 (pH 9) and 0.2 M sodium pyrosulfite solution and extracted two times with CH2Cl2. The combined organic layers were washed with brine, dried over Na2SO4, filtered and the solvent was evaporated. The residue was purified by flash chromatography (silica gel, gradient of heptane in ethyl acetate) to give the title compound as a colorless solid (9.35 g, 55%). MS (m/e)=275.9 [M+H+].

1. stirringStirring
2. waitwas continued for 1 hour at 0° C
3. stirringStirring
4. waitwas continued for 10 minutes
5. customThe reaction mixture was then evaporated to dryness
6. dissolutionThe residue was dissolved in CH2Cl2
7. additionthe solution was poured into sat. Na2CO3 (pH 9) and 0.2 M sodium pyrosulfite solution
8. extractionextracted two times with CH2Cl2
9. washThe combined organic layers were washed with brine
10. dry with materialdried over Na2SO4
11. filtrationfiltered
12. customthe solvent was evaporated
13. customThe residue was purified by flash chromatography (silica gel, gradient of heptane in ethyl acetate)