Reaktion #589022

Reaktionsgleichung

6-(4-aminophenoxy)-hexanoic acid methyl ester

triethylamine

triphosgene

→

18

Ausbeute 72.3%

6-(4-Isocyanatophenoxy)-hexanoic acid methyl ester

Ausbeute 72.3%

Lösungsmittel

toluene

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigerose to 60° C
2. 2
   Temperaturmaintained at this temperature for 26 hours
3. 3
   TemperaturThe reaction mixture was cooled to room temperature
4. 4
   Filtrationthe solids filtered off
5. 5
   workup.DISTILLATIONtoluene distilled off under vacuum
6. 6
   Sonstigeto get crude 18, which
7. 7
   workup.DISTILLATIONdistilled

Vorschrift

To 6-(4-aminophenoxy)-hexanoic acid methyl ester 17 (26 g, 109.7 mmol) and triethylamine (29.2 g, 288.56 mmol) in toluene (390 ml) under nitrogen atmosphere was added triphosgene (15.6 g, 52.56 mmol) in one lot. The reaction was exothermic and 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 filtered off, and toluene distilled off under vacuum to get crude 18, which was vacuum distilled to get pure 18 (10 g, 34.7%) with an m.p between 47-50° C.

Quelle