Reaction #2045024

Reaction equation

6-(4-amino-phenoxy)hexanoic acid methyl ester

6-(4-Amino-phenoxy)-hexanoic acid methyl ester

triethylamine

triphosgene

→

36

Yield 72.3%

6-(4-Isocyanato-phenoxy)-hexanoic acid methyl ester

Yield 72.3%

Solvents

toluene

Conditions

Workup

1. 1
   Otherrose to 60° C
2. 2
   Temperaturemaintained at this temperature for 26 hours
3. 3
   TemperatureThe reaction mixture was cooled to room temperature
4. 4
   Filtrationthe solids were filtered
5. 5
   workup.DISTILLATIONthe toluene was distilled off under vacuum
6. 6
   Otherto get crude 36, which
7. 7
   workup.DISTILLATIONdistilled

Procedure

To a mixture of 6-(4-amino-phenoxy)hexanoic acid methyl ester 21 (26 grams, 109.7 mmol) and triethylamine (29.2 g, 288.56 mmol) in toluene (390 ml) under nitrogen atm. was added triphosgene (15.6 grams, 52.56 mmol) in one lot. The reaction was exothermic and the internal temperature rose to 60° 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 cooled to room temperature, the solids were filtered, and the toluene was distilled off under vacuum to get crude 36, which was vacuum distilled to get pure 36 (10 g, 34.7%). M.p: 47-50° C.

Source