反应详情

A solution of 3.1 g. (0.01 mole) of the product of step D and 2 g. of dinitrogen tetraoxide in 250 ml. of chloroform is stirred at about 20° C. for about 16 hours. Evaporation of the mixture provides a residue which is dissolved in 10 percent sodium hydroxide solution, then acidified with hydrochloric acid. The precipitate is collected by filtration, dissolved in a chloroform/ethanol mixture and chromatographed on silica gel, eluting with chloroform. The solid obtained is recrystallized twice from a mixture of water and N,N-dimethylformamide to provide yellow crystals of 4-(2-nitro-3-phenylbenzofuran-5-yl)benzoic acid, m.p. 259°-261° C.

1. customEvaporation of the mixture
2. customprovides a residue which
3. filtrationThe precipitate is collected by filtration
4. dissolutiondissolved in a chloroform/ethanol mixture
5. customchromatographed on silica gel
6. washeluting with chloroform
7. customThe solid obtained
8. customis recrystallized twice from a mixture of water and N,N-dimethylformamide