1-(4-chlorophenyl)pyrrole-2,5-dione

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of 19.4 g (93 mmol) of 1-(4-chloro-phenyl)-pyrrole-2,5-dione in 120 ml of xylene was treated with 19.4 ml (187 mmol) of ethyldiazoacetate and refluxed during 12 hrs. Evaporation of the solvent and chromatography on silica gel with toluene and then a gradient of toluene/AcOEt from 95:5 to 90:10 gave 9.5 g(35%) of the title compound. Off white solid. MS: 294 (M+H)+. refluxed during 12 hrs Evaporation of the solvent and chromatography on silica gel with toluene

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: In Analogy to the procedure given in Mhaske et al., Synthesis, 2003, p863-870: A solution of 65 g (288 mmol) of (Z)-3-(4-chloro-phenylcarbamoyl)-acrylic acid in 300 ml of benzene was treated with 41.2 g (302 mmol) of zinc dichloride, dropwise with 90.1 ml (432 mmol) of bis(trimethylsilyl)amine and refluxed during 5 hrs. The mixture was poured into 300 ml of aqueous HCl (0.5 M). The aqueous phase was extracted with AcOEt, the combined organic phases were washed successively with saturated aqueous NaHCO3 and brine, and finally dried over Na2SO4. Evaporation of the solvent gave 58 g (97%) of the title compound. Brown amorphous solid. MS: 208 (M+H)+. In Analogy to the procedure given in Mhaske et al., Synthesis, 2003, p863-870 refluxed during 5 hrs The aqueous phase was extracted with AcOEt the combined organic phases were washed successively with saturated aqueous NaHCO3 and brine finally dried over Na2SO4 Evaporation of the solvent