4-(2,3-dichlorophenyl)-1H-pyrrole-3-carbonitrile

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

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

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

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: 3.2 g of the 3-hydroxyiminomethyl-4-(2,3-dichlorophenyl)pyrrole obtained in (b) are kept for 5 hours at c. 100° C. in 50 ml of acetic anhydride, then cooled to room temperature, poured into ice/NaOH, and the resultant mixture is stirred for 2 hours. The precipitate is dissolved in ethyl acetate, washed with water, the exter phase is dried over magnesium sulfate. The residue is purified by column chromatography (silica gel; elution with a 4:1 mixture of toluence/ethyl acetate). Melting point: 149°-151° C. washed with water the exter phase is dried over magnesium sulfate The residue is purified by column chromatography (silica gel elution with a 4:1 mixture of toluence/ethyl acetate)

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

Procedure: 3.2 g of the 3-hydroxyiminomethyl-4-(2,3-dichlorophenyl)pyrrole obtained in (b) are kept for 5 hours at c. 100° C. in 50 ml of acetic anhydride, then cooled to room temperature, poured into ice/NaOH, and the resultant mixture is stirred for 2 hours. The precipitate is dissolved in ethyl acetate, washed with water, the exter phase is dried over magnesium sulfate. The residue is purified by column chromatography (silica gel; elution with a 4:1 mixture of toluence/ethyl acetate). Melting point: 149°-151° C. washed with water the exter phase is dried over magnesium sulfate The residue is purified by column chromatography (silica gel elution with a 4:1 mixture of toluence/ethyl acetate)

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

Procedure: 2.1 g of the free 4-(2,3-dichlorophenyl)pyrrole-3-carboxylic acid obtained in (b) are dissolved in 30 ml of ethanol. The solution is made alkaline with concentrated ammonia and then evaporated to dryness. The residue is dissolved in 50 ml of ethanol. NH3 gas is added (20 atm) to this solution at room temperature in an autoclave and the reaction mixture is kept for 15 hours at 220° C. The reaction mixture, which has cooled to room temperature, is poured into ice/HCl, the precipitate is isolated by filtration and dried at 60° C. The resultant powder is heated with 17 g of polyphosphoric acid in an open vessel at 180° C., the hot mixture is dropped onto ice, made alkaline with NaOH and extracted with ethyl acetate. The combined extracts are concentrated by evaporation and the residue is purified by column chromatography (silica gel; elution with a 4:1 mixture of toluene/ethyl acetate), affording 4-(2,3-dichlorophenyl)-3-cyanopyrrole of m.p. 148°-150° C. evaporated to dryness The residue is dissolved in 50 ml of ethanol NH3 gas is added (20 atm) to this solution at room temperature in an autoclave is poured into ice/HCl the precipitate is isolated by filtration dried at 60° C The resultant powder is heated with 17 g of polyphosphoric acid in an open vessel at 180° C. the hot mixture is dropped onto ice extracted with ethyl acetate The combined extracts are concentrated by evaporation the residue is purified by column chromatography (silica gel elution with a 4:1 mixture of toluene/ethyl acetate),

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

Procedure: 2.1 g of the free 4-(2,3-dichlorophenyl)pyrrole-3-carboxylic acid obtained in (b) are dissolved in 30 ml of ethanol. The solution is made alkaline with concentrated ammonia and then evaporated to dryness. The residue is dissolved in 50 ml of ethanol. NH3 gas is added (20 atm) to this solution at room temperature in an autoclave and the reaction mixture is kept for 15 hours at 220° C. The reaction mixture, which has cooled to room temperature, is poured into ice/HCl, the precipitate is isolated by filtration and dried at 60° C. The resultant powder is heated with 17 g of polyphosphoric acid in an open vessel at 180° C., the hot mixture is dropped onto ice, made alkaline with NaOH and extracted with ethyl acetate. The combined extracts are concentrated by evaporation and the residue is purified by column chromatography (silica gel; elution with a 4:1 mixture of toluene/ethyl acetate), affording 4-(2,3-dichlorophenyl)-3-cyanopyrrole of m.p. 148°-150° C. evaporated to dryness The residue is dissolved in 50 ml of ethanol NH3 gas is added (20 atm) to this solution at room temperature in an autoclave is poured into ice/HCl the precipitate is isolated by filtration dried at 60° C The resultant powder is heated with 17 g of polyphosphoric acid in an open vessel at 180° C. the hot mixture is dropped onto ice extracted with ethyl acetate The combined extracts are concentrated by evaporation the residue is purified by column chromatography (silica gel elution with a 4:1 mixture of toluene/ethyl acetate),

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

Procedure: 4.2 g of the 3-(2,3-dichlorophenacylamino)acrylonitrile obtained in (a) are reacted in 50 ml of ethanol with 0.5 g of sodium ethylate as described in Example P5(b), affording the title compound in quantitative yield. Melting point: 150°-152° C.

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

Procedure: 4.2 g of the 3-(2,3-dichlorophenacylamino)acrylonitrile obtained in (a) are reacted in 50 ml of ethanol with 0.5 g of sodium ethylate as described in Example P5(b), affording the title compound in quantitative yield. Melting point: 150°-152° C.

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

Procedure: 20.0 g of 2,3-dichlorophenacylamine hydrochloride and 10.0 g of 3-dimethylaminoacrylonitrile are heated for 1 hour under reflux in 300 ml of ethanol. Then an ethanolic solution of sodium ethylate, prepared from 2.1 g of sodium and 30 ml of ethanol, is rapidly added dropwise and the reaction mixture is stirred for another 10 minutes under reflux. The reaction mixture is cooled to room temperature and then poured into ice/hydrochloric acid and the resultant mixture is stirred for 11/2 hours. The precipitate is isolated by filtration, washed with water and dried, affording 15.4 g (78% of theory) of title compound with a melting point of 152°-154° C. is rapidly added dropwise under reflux The precipitate is isolated by filtration washed with water dried