反应详情

Fuming nitric acid (0.2 ml.) was added during 10 minutes to a stirred solution of 1'-(3,4-dichlorobenzyl)-spiro[imidazolidine-4,3'-indoline]-2,2',5-trione (1.79 g.) in concentrated sulphuric acid (1.5 ml.) maintained at a temperature of 0°-5° C. The reaction mixture was then stirred at 0°-5° C. for 1 hour and finally at 5°-20° C. for a further 1 hour. The solution was then poured onto crushed ice (300 g.) and the mixture which formed was extracted with ethyl acetate. The combined extracts were washed with water (3×150 ml.) then with brine (100 ml.) and dried (MgSO4). The extracts were evaporated and the residual oil was redissolved in ethyl acetate (20 ml.). The solution was evaporated on to chromatographic silica gel and the solid residue added to the top of a column of the same silica gel made up in toluene. The column was eluted with increasing concentrations of ethyl acetate in toluene (up to 1:1 v/v). The fractions containing the major component [TLC:Rf~0.6 on SiO2 :eluant 1:1 v/v EtOAc/toluene] were combined and evaporated. The residue was recrystallised from a mixture of toluene, ethyl acetate and petrol 60-80 to give 1'-(3,4-dichlorobenzyl)-5'-nitro-spiro[imidazolidine-4,3'-indoline]-2,2',5-trione (Prep. 35) (0.46 g.), m.p. 249°-251° C.

1. temperaturemaintained at a temperature of 0°-5° C
2. additionThe solution was then poured
3. customthe mixture which formed
4. extractionwas extracted with ethyl acetate
5. washThe combined extracts were washed with water (3×150 ml.)
6. dry with materialwith brine (100 ml.) and dried (MgSO4)
7. customThe extracts were evaporated
8. dissolutionthe residual oil was redissolved in ethyl acetate (20 ml.)
9. customThe solution was evaporated on to chromatographic silica gel
10. additionthe solid residue added to the top of a column of the same silica gel
11. washThe column was eluted
12. temperaturewith increasing concentrations of ethyl acetate in toluene (up to 1:1 v/v)
13. additionThe fractions containing the major component [TLC:Rf~0.6 on SiO2 :eluant 1:1 v/v EtOAc/toluene]
14. customevaporated
15. customThe residue was recrystallised from a mixture of toluene, ethyl acetate and petrol 60-80