Nitric Acid → HCID 20434007, compound

Participants

Reaction Steps

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'-nitrospiro[imidazolidine-4,3'-indoline]-2,2',5-trione (Example 35) (0.46 g.), m.p. 249°-251° C.

Provenance & Evidence