Réaction #170963

Équation de réaction

2-(4-aminophenoxy)-propionic acid

2-(4-Amino-phenoxy)-propionic acid

methanol

HCl

→

10

Rendement 37.2%

2-(4-Amino-phenoxy)-propionic acid methyl ester

Rendement 37.2%

Conditions de réaction

Traitement

1. 1
   Autreat 10° C.
2. 2
   Autrefor 1 hour
3. 3
   Températureby reflux for 48 hours
4. 4
   workup.DISTILLATIONMethanol (2.5 liter) was distilled off
5. 5
   workup.ADDITIONice water (1 liter) was added
6. 6
   ExtractionCrude 10 was extracted into chloroform
7. 7
   Lavagewashed with 5% NaHCO3 solution, water
8. 8
   Séchagedried over Na2SO4
9. 9
   workup.DISTILLATIONdistilled

Mode opératoire

Method-A Through a mixture of 2-(4-aminophenoxy)-propionic acid 9 (240 g, 1.103 mmol) in methanol (4.8 liters) was passed dry HCl gas at 10° C. for 1 hour followed by reflux for 48 hours. Methanol (2.5 liter) was distilled off, ice water (1 liter) was added and the pH was adjusted to 7.5 with K2CO3. Crude 10 was extracted into chloroform, washed with 5% NaHCO3 solution, water, dried over Na2SO4 and distilled to give 10 (80 g, 37.2%) as a brown syrup. Method-B 2-(4-Nitrophenoxy)-propionic acid methyl ester 14 (20 g, 88.88 mmol) was dissolved in dimethyl formamide (100 ml) in a pressure vessel, Raney nickel (20 grams) was added and the mixture stirred under an atmosphere of hydrogen (4 kg) for 6 hours. The catalyst was removed by filtration and the dimethyl formamide distilled off under vacuum. Crude 10 was purified by column chromatography on silica gel using chloroform as eluant to get pure 10 (15 g, 86.55%) as a brown syrup.

Source