Reaction #2045017

Reaction equation

(4-Amino-phenoxy)-acetic acid methyl ester

triethylamine

triphosgene

→

28

Yield 159.1%

(4-Isocyanato-phenoxy)-acetic acid methyl ester

Yield 159.1%

Solvents

toluene

Conditions

Workup

1. 1
   TemperatureLater the reaction mixture was heated to 75° C. over a period of one hour
2. 2
   Temperaturemaintained at this temperature for 26 hours
3. 3
   TemperatureThe reaction mixture was then cooled to room temperature
4. 4
   Filtrationthe solids were filtered off
5. 5
   workup.DISTILLATIONthe toluene was distilled off under vacuum
6. 6
   Otherto get crude 28, which
7. 7
   workup.DISTILLATIONdistilled

Procedure

To a mixture of (4-Amino-phenoxy)-acetic acid methyl ester 15 (15 g, 82.87 mmol) and triethylamine (16.77 g, 165.73 mmol) in toluene (225 ml) under nitrogen atm. at 0° C. was added triphosgene (9 g, 30.33 mmol) in one lot. The reaction was exothermic and the temperature raised to 25° C. Later the reaction mixture was heated to 75° C. over a period of one hour and maintained at this temperature for 26 hours. The reaction mixture was then cooled to room temperature, the solids were filtered off, and the toluene was distilled off under vacuum to get crude 28, which was vacuum distilled to get pure 28 (10 g, 58.3%) as a white powder. M.p: 50-53° C.

Source