反应详情

3,4-Dichloroanthranilic acid (61.8 g) was stirred in THF at -15° C., and triethylamine was added. Methyl chloroformate (36.9 g) was then added at -15° C. and the mixture stirred for 45 minutes. Water was then added, followed by concentrated hydrochloric aicd solution until pH 1 was achieved, and the solution was stirred overnight. Excess water was added and the mixture was extracted with ethyl acetate. The extract was washed with water, dried (anhydrous magnesium sulphate) and the solvent evaporated. The resulting solid was recrystallised from a solution of toluene and cyclohexane to give 3,4-dichloro-2-(methoxycarbonylamino)benzoic acid (65.1 g) as a fawn solid, m.p. 155-156° C.

1. stirringthe solution was stirred overnight
2. extractionthe mixture was extracted with ethyl acetate
3. washThe extract was washed with water
4. dry with materialdried (anhydrous magnesium sulphate)
5. customthe solvent evaporated
6. customThe resulting solid was recrystallised from a solution of toluene and cyclohexane