ethyl N-phenylcarbamate

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:

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: A 25 ml egg-plant type flask was flushed with argon, and 85.9 mg (0.52 mmol) of phenylurethane, 2 ml of dry 1,2-dichloroethane and 110.2 mg (0.52 mmol) of N-fluoro-2-chloropyridinium-6-sulfonate were charged. The flask was immersed in an oil bath of 80° C. and heated for 72 hours. Then, 20 ml of water was added thereto, and the mixture was extracted with methylene chloride (20 ml×3 times). 2-Chloropyridine-6-sulfonic acid formed after the reaction was all transferred to the aqueous layer. The organic layer was washed with water and dried over anhydrous magnesium sulfate. Then, the solvent was removed under reduced pressure. The residue was purified by thin layer chromatography (eluent: hexane/ethyl acetate=9/1) to obtain 58.6 mg (conversion yield: 73%) of 2-fluorophenylurethane, 4.9 mg (conversion yield: 6%) of 4-fluorophenylurethane and 2.8 mg (conversion yield: 3%) of 2,4-difluorophenyl-urethane. 14.1 mg of phenylurethane was recovered (recovery rate: 16%). were charged The flask was immersed in an oil bath of 80° C. heated for 72 hours the mixture was extracted with methylene chloride (20 ml×3 times)

Conditions: temp:100.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 165 parts of ethyl N-phenylcarbamate and 10 grams of p-toluenesulfonic acid is heated, in a stirred autoclave, to 100° C. whilst stirring, and 112 parts of isobutene are pumped in over two hours. After completion of the addition of isobutene, the mixture is stirred for a further two hours at 100° C. It is then diluted with 100 parts of toluene and extracted with aqueous sodium carbonate solution, and the end product is distilled under reduced pressure. 169 parts (72% of theory, based on carbamic acid ester II) of ethyl N-(4-tert.-butylphenyl)-carbamate, of boiling point 125°-127° C./0.2 mbar, are obtained. The conversion is 76 percent. are pumped in over two hours the mixture is stirred for a further two hours at 100° C extracted with aqueous sodium carbonate solution the end product is distilled under reduced pressure

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

Procedure: To a stirred solution of trimethylsilyl ethanol (1.2 mmol, 0.14 g) in THF (3.8 mL) under argon at room temperature is added 1M solution of potassium tert-butoxide in THF (1.2 mL, 1.19 mmol) The reaction mixture is stirred for 40 minutes and then added dropwise over 5-10 minutes to a stirred solution of the above phenyl urethane (0.45 g, 1.1 mmol) in THF (3.8 ml) at 5° C. The reaction mixture is stirred at this temperature for 20 minutes and then warmed to room temperature for 16 hours. After refluxing for 40 minutes the reaction is cooled to room temperature and partitioned between ethyl acetate and water; the aqueous phase is extracted twice with ethyl acetate. The combined organic phases are washed with brine, dried (Na2SO4) and concentrated. The residue is purified by flash chromatography (10% ethyl acetate/hexane) to give the intermediate silylethoxy urethane (0.22 g, 48%); Rf=0.56 (20% ethyl acetate/hexane). MS (EI) m/z (419 M+). The reaction mixture is stirred at this temperature for 20 minutes After refluxing for 40 minutes the reaction is cooled to room temperature partitioned between ethyl acetate and water the aqueous phase is extracted twice with ethyl acetate The combined organic phases are washed with brine dried (Na2SO4) concentrated The residue is purified by flash chromatography (10% ethyl acetate/hexane)