ethyl N-(4-chlorophenyl)carbamate

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

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

Procedure: Ethyl 4-chlorophenylcarbamate (1.2281 g) was dissolved in tetrahydrofuran (30 ml), and to the solution were added sodium hydride (246.1 mg) and 2-chloro-3,5-dinitrobenzotrifluoride (1.3870 g). The reaction mixture was stirred at room temperature for 2 hours. To the reaction mixture was added 1N hydrochloric acid, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated brine, dried over anhydrous magnesium sulfate, and concentrated in vacuo. The resultant residue was purified by silica gel column (75 g, hexane:ethyl acetate=5:1) to give the title compound (1.7323 g, 78%). the mixture was extracted with ethyl acetate The organic layer was washed with saturated brine dried over anhydrous magnesium sulfate concentrated in vacuo The resultant residue was purified by silica gel column (75 g, hexane:ethyl acetate=5:1)

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

Procedure: Ethyl 4-chlorophenylcarbamate (1.2281 g) was dissolved in tetrahydrofuran (30 ml), and to the solution were added sodium hydride (246.1 mg) and 2-chloro-3,5-dinitrobenzotrifluoride (1.3870 g). The reaction mixture was stirred at room temperature for 2 hours. To the reaction mixture was added 1N hydrochloric acid, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated brine, dried over anhydrous magnesium sulfate, and concentrated in vacuo. The resultant residue was purified by silica gel column (75 g, hexane:ethyl acetate=5:1) to give the title compound (1.7323 g, 78%). the mixture was extracted with ethyl acetate The organic layer was washed with saturated brine dried over anhydrous magnesium sulfate concentrated in vacuo The resultant residue was purified by silica gel column (75 g, hexane:ethyl acetate=5:1)

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

Procedure: 4-Chloroaniline (2.3531 g) was dissolved in pyridine (20 ml), and to the solution was added dropwise ethyl chloroformate (2.116 ml) under ice-cooling. After the mixture was stirred for 1.5 hours, 1N hydrochloric acid was added and the mixture was extracted with ethyl acetate. The organic layer was washed with 1N hydrochloric acid, and then saturated brine, dried over anhydrous magnesium sulfate, and concentrated in vacuo to give the title compound (3.6875 g, quantitative yield). cooling the mixture was extracted with ethyl acetate The organic layer was washed with 1N hydrochloric acid saturated brine, dried over anhydrous magnesium sulfate 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: Ethyl N-(4-chlorophenyl)carbamate (2.02 g, 10.1 mmol), ethyl 2-hydroxy-3-methyl-3-butenoate (2.97 g, 22.8 mmol) and tetrabutylammonium bromide (243 mg, 1.5 mmol) were introduced into a flask (25 cc) equipped with a distillation unit, and the reaction was conducted at 200° C. for 3.5 hours. After the reaction solution was cooled to room temperature, toluene (20 mL) was added, and then the reaction solution was washed with water (20 mL), then 1N sodium hydroxide (20 mL) and 1N hydrochloric acid (20 mL). The organic layer was dried over magnesium sulfate. After the drying agent was filtered off, the filtrate was concentrated under reduced pressure. To the resulting oily crude product, a mixed solvent consisting of methanol (5 mL) and 6N hydrochloric acid (0.25 mL) was added. The precipitated solid was collected by filtration, then washed with a 10:1 mixed solvent consisting of methanol and 6N hydrochloric acid and dried to obtain 3-(4-chlorophenyl)-5-isopropylidene-1,3-oxazolidine-2,4-dione (1.03 g, yield 40.5%). equipped with a distillation unit the reaction solution was washed with water (20 mL) The organic layer was dried over magnesium sulfate After the drying agent was filtered off the filtrate was concentrated under reduced pressure was added The precipitated solid was collected by filtration washed with a 10:1 mixed solvent dried

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

Procedure: Ethyl N-(4-chlorophenyl)carbamate (2.02 g, 10.1 mmol), ethyl 2-hydroxy-3-methyl-3-butenoate (2.97 g, 22.8 mmol) and tetrabutylammonium bromide (243 mg, 1.5 mmol) were introduced into a flask (25 cc) equipped with a distillation unit, and the reaction was conducted at 200° C. for 3.5 hours. After the reaction solution was cooled to room temperature, toluene (20 mL) was added, and then the reaction solution was washed with water (20 mL), then 1N sodium hydroxide (20 mL) and 1N hydrochloric acid (20 mL). The organic layer was dried over magnesium sulfate. After the drying agent was filtered off, the filtrate was concentrated under reduced pressure. To the resulting oily crude product, a mixed solvent consisting of methanol (5 mL) and 6N hydrochloric acid (0.25 mL) was added. The precipitated solid was collected by filtration, then washed with a 10:1 mixed solvent consisting of methanol and 6N hydrochloric acid and dried to obtain 3-(4-chlorophenyl)-5-isopropylidene-1,3-oxazolidine-2,4-dione (1.03 g, yield 40.5%). equipped with a distillation unit the reaction solution was washed with water (20 mL) The organic layer was dried over magnesium sulfate After the drying agent was filtered off the filtrate was concentrated under reduced pressure was added The precipitated solid was collected by filtration washed with a 10:1 mixed solvent dried

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

Procedure: 26.6 g of 4-nitrochlorobenzene, 2.0 g of sulphur, 0.2 g of metallic selenium, 4.4 g of 4-chloroaniline, 2.36 g of potassium acetate, 3 g of the metal oxide mixture used in Example 1, 1.28 g of di-n-butylamine and 169 g of absolute ethanol were reacted together at 180° C. as described in Example 1. The reaction mixture was worked up as described in Example 1 and yielded 24.5 g of ethyl-N-(4-chlorophenyl)-carbamate, b.p. 118°-120° C./0.2 mm. The substance was 98.5% pure according to gas chromatographic analysis. were reacted together at 180° C.

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

Procedure: 26.6 g of 4-nitrochlorobenzene, 2.0 g of sulphur, 0.2 g of metallic selenium, 4.4 g of 4-chloroaniline, 2.36 g of potassium acetate, 3 g of the metal oxide mixture used in Example 1, 1.28 g of di-n-butylamine and 169 g of absolute ethanol were reacted together at 180° C. as described in Example 1. The reaction mixture was worked up as described in Example 1 and yielded 24.5 g of ethyl-N-(4-chlorophenyl)-carbamate, b.p. 118°-120° C./0.2 mm. The substance was 98.5% pure according to gas chromatographic analysis. were reacted together at 180° C.

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

Procedure: 26.6 g of 4-nitrochlorobenzene, 2.0 g of sulphur, 0.2 g of metallic selenium, 4.4 g of 4-chloroaniline, 2.36 g of potassium acetate, 3 g of the metal oxide mixture used in Example 1, 1.28 g of di-n-butylamine and 169 g of absolute ethanol were reacted together at 180° C. as described in Example 1. The reaction mixture was worked up as described in Example 1 and yielded 24.5 g of ethyl-N-(4-chlorophenyl)-carbamate, b.p. 118°-120° C./0.2 mm. The substance was 98.5% pure according to gas chromatographic analysis. were reacted together at 180° C.

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

Procedure: Following the procedure described in Example 1, 638 g of 4-chloroaniline, 240 g of urea, 89 g of ethyl carbamate, 625 g of ethanol (approximately 96%) and 1400 g of chlorobenzene were reacted for 6.5 hours at 200° C. in the pressure apparatus described in Example 1. After the apparatus had been cooled and vented, the reaction mixture was removed. Excess ethanol was removed by fractional distillation at atmospheric pressure. The mixture (while being stirred) was then exposed to hydrogen chloride gas at room temperature, filtered and subjected to fractional distillation in vacuo. Chlorobenzene was separated off at 15 mbar. Subsequent distillation at 0.2 mbar yielded 785 g (78.6% of the theoretical yield) of N-(4-chlorophenyl)-carbamic acid ethyl ester melting at from 68° to 70° C. were reacted for 6.5 hours at 200° C. in the pressure apparatus After the apparatus had been cooled the reaction mixture was removed Excess ethanol was removed by fractional distillation at atmospheric pressure was then exposed to hydrogen chloride gas at room temperature filtered subjected to fractional distillation in vacuo Chlorobenzene was separated off at 15 mbar Subsequent distillation at 0.2 mbar yielded 785 g (78.6% of the

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

Procedure: Ethyl 4-chlorophenylcarbamate (1.2281 g) was dissolved in tetrahydrofuran (30 ml), and to the solution were added sodium hydride (246.1 mg) and 2-chloro-3,5-dinitrobenzotrifluoride (1.3870 g). The reaction mixture was stirred at room temperature for 2 hours. To the reaction mixture was added 1N hydrochloric acid, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated brine, dried over anhydrous magnesium sulfate, and concentrated in vacuo. The resultant residue was purified by silica gel column (75 g, hexane:ethyl acetate=5:1) to give the title compound (1.7323 g, 78%). the mixture was extracted with ethyl acetate The organic layer was washed with saturated brine dried over anhydrous magnesium sulfate concentrated in vacuo The resultant residue was purified by silica gel column (75 g, hexane:ethyl acetate=5:1)