反应详情

To a solution of methyl 2-fluoro-3,5-dinitrobenzoate (D137) (24.4 g, 0.1 mol, 1 equiv) in AcOH (1 l) was added iron (27.5 g, 0.5 mol, 5 equiv) and the resulting suspension was vigorously stirred for 1 h. The temperature was kept below 35° C. by small amount of cooling using an ice bath during that period. Toluene (200 ml) was added and the suspension filtered through a pad of celite. The remaining solution was concentrated in vacuo and the residue partitioned between AcOEt and a saturated aqueous NaHCO3 solution. The two layers were separated and the aqueous phase was extracted twice with AcOEt. The combined organic phases were dried over MgSO4 and concentrated in vacuo to give methyl 3-amino-2-fluoro-5-nitrobenzoate (D138) (17 g, 79%) as a yellow solid which was used in the next step without further purification. [M−H]−=212.9, RT=2.68 min.

1. customwas kept below 35° C. by small amount
2. temperatureof cooling
3. filtrationthe suspension filtered through a pad of celite
4. concentrationThe remaining solution was concentrated in vacuo
5. customthe residue partitioned between AcOEt
6. customThe two layers were separated
7. extractionthe aqueous phase was extracted twice with AcOEt
8. dry with materialThe combined organic phases were dried over MgSO4
9. concentrationconcentrated in vacuo