ethyl 2-(4-chlorophenyl)acetate

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:-78.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of freshly prepared lithium diisopropylamide (23.0 mL of 0.31M stock solution, 7.13 mmol) cooled to −78° C. was treated with (4-chloro-phenyl)-acetic acid ethyl ester (1.28 g, 6.48 mmol) in tetrahydrofuran/hexamethylphosphoramide (16.1 mL, 3:1). The resulting solution was stirred at −78° C. for 45 min. At this time, the reaction was treated with a solution of iodomethylcyclopentane (1.50 mg, 7.13 mmol) in hexamethylphosphoramide (1 mL). The reaction-mixture was stirred at −78° C. for 4 h. The reaction was warmed to 25° C. and stirred at 25° C. for 16 h. The reaction mixture was then quenched by the dropwise addition of a saturated aqueous ammonium chloride solution (20 mL). This mixture was poured into water (100 mL) and extracted with ethyl acetate (3×50 mL). The combined organic layers were dried over sodium sulfate, filtered, and concentrated in vacuo. Flash chromatography (Merck Silica gel 60, 230-400 mesh, 75/25 hexanes/ethyl acetate) afforded 2-(4-chloro-phenyl)-3-cyclopentyl-propionic acid ethyl ester (1.65 g, 90.9%) as a yellow oil: EI-HRMS m/e calcd for C16H21Cl2O2 (M+) 280.1230, found 280.1227. The reaction-mixture was stirred at −78° C. for 4 h The reaction was warmed to 25° C. stirred at 25° C. for 16 h The reaction mixture was then quenched by the dropwise addition of a saturated aqueous ammonium chloride solution (20 mL) This mixture was poured into water (100 mL) extracted with ethyl acetate (3×50 mL) The combined organic layers were dried over sodium sulfate filtered concentrated in vacuo

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

Procedure: A solution of (4-chloro-phenyl)-acetic acid (6.29 g, 0.03 mol) in ethanol (38.4 mL) was treated with a catalytic amount of sulfuric acid. The reaction mixture was heated under reflux for 12 h. The reaction was then concentrated in vacuo. Flash chromatography (Merck Silica gel 60, 230-400 mesh, 50/50 hexanes/ethyl acetate) afforded (4-chloro-phenyl)-acetic acid ethyl ester (6.45 g, 88%) as a pale yellow solid: mp 39-41° C.; EI-HRMS m/e calcd for C10H11ClO2 (M+) 198.0448, found 198.0452. The reaction mixture was heated under reflux for 12 h The reaction was then concentrated in vacuo

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

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

Procedure: 19.9 g (0.1 mole) of ethyl 4-chloro-phenylacetate are heated at 100° C. with 23.8 g (0.2 mole) of dimethylformamide dimethyl acetal for 5 hours. All the volatile constituents are then distilled off at this temperature under a waterpump vacuum. The oily residue, which essentially consists of ethyl α-dimethylaminomethylene-4-chlorophenylacetate, is dissolved, without further purification, in 140 ml of ethanol. 11 g (0.1 mole) of 2-hydrazinopyrimidine and 10 ml of concentrated hydrochloric acid are added. The mixture is heated under reflux for 5 hours, cooled to room temperature and, after addition of 9 g of concentrated sodium hydroxide solution, stirred at room temperature for 5 hours. After neutralization with dilute hydrochloric acid, the mixture is diluted with 1 liter of water. The crystals which have separated out are filtered off with suction, washed with water and dried in air. 7.2 g (26.4% of theory) of 1-pyrimid-2-yl-4-(4-chloro-phenyl)pyrazolin-5-one are obtained. Melting point: 190° to 191° C. (methanol). All the volatile constituents are then distilled off at this temperature under a waterpump vacuum is dissolved, without further purification, in 140 ml of ethanol The mixture is heated under reflux for 5 hours The crystals which have separated out are filtered off with suction washed with water dried in air

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

Procedure: 19.9 g (0.1 mole) of ethyl 4-chloro-phenylacetate are heated at 100° C. with 23.8 g (0.2 mole) of dimethylformamide dimethyl acetal for 5 hours. All the volatile constituents are then distilled off at this temperature under a waterpump vacuum. The oily residue, which essentially consists of ethyl α-dimethylaminomethylene-4-chlorophenylacetate, is dissolved, without further purification, in 140 ml of ethanol. 11 g (0.1 mole) of 2-hydrazinopyrimidine and 10 ml of concentrated hydrochloric acid are added. The mixture is heated under reflux for 5 hours, cooled to room temperature and, after addition of 9 g of concentrated sodium hydroxide solution, stirred at room temperature for 5 hours. After neutralization with dilute hydrochloric acid, the mixture is diluted with 1 liter of water. The crystals which have separated out are filtered off with suction, washed with water and dried in air. 7.2 g (26.4% of theory) of 1-pyrimid-2-yl-4-(4-chloro-phenyl)pyrazolin-5-one are obtained. Melting point: 190° to 191° C. (methanol). All the volatile constituents are then distilled off at this temperature under a waterpump vacuum is dissolved, without further purification, in 140 ml of ethanol The mixture is heated under reflux for 5 hours The crystals which have separated out are filtered off with suction washed with water dried in air

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

Procedure: To p-chlorophenylacetic acid (85.30 g, 0.50 mole) was added ethanol (92 g, 2.0 mole), benzene (78.11 g) and conc. sulfuric acid (2.5 g, 0.025 mole) and the azeotropic dehydration reaction was performed for 6 hours. After completion of the reaction, water (200 ml) was added to the reaction mixture, while it was cool and the solution was extracted with diethyl ether. The ether layer was dried with anhydrous sodium sulfate, diethyl ether was distilled off under reduced pressure and the resulting residue was distilled under reduced pressure to give 96.30 g (96.9%) of the title compound as a colorless liquid, b.p. 105°-106° C./2.5 mmHg (lit. 130° C./13 mmHg). the azeotropic dehydration reaction was added to the reaction mixture, while it was cool the solution was extracted with diethyl ether The ether layer was dried with anhydrous sodium sulfate, diethyl ether was distilled off under reduced pressure the resulting residue was distilled under reduced pressure

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

Procedure: Then, 4.19 g of sodium hydride (60% in oil) was suspended in 150 ml of tetrahydrofuran, to which a solution of 19.0 g of ethyl 4-chlorophenylacetate in 150 ml of tetrahydrofuran was added dropwise at 5° to 10° C. After stirring at room temperature for 1.5 hours, 8.42 g of ethyl formate was added, and the mixture was further stirred at room temperature for 4.5 hours. After completion of the reaction, the reaction mixture was cooled to ice temperature, neutralized by the addition of diluted hydrochloric acid, and concentrated. The residue was subjected to phase separation with ethyl acetatewater, and the organic layer was dried and then concentrated. The residue was subjected to silica gel chromatography, which afforded 17.0 g of ethyl 2-(4′-chlorophenyl)-2-formylacetate. was added dropwise at 5° to 10° C the mixture was further stirred at room temperature for 4.5 hours After completion of the reaction the reaction mixture was cooled to ice temperature concentrated The residue was subjected to phase separation with ethyl acetatewater the organic layer was dried concentrated