Reaktion #947784

Reaktionsgleichung

N,O-dimethyl hydroxylamine hydrochloride

2-(4-Trifluoromethyl-benzoylamino)-propionic acid

oxalyl chloride

hydrochloric acid

triethylamine

→

4-methyl-2-(4-trifluoromethyl-phenyl)-oxazole-5-carboxylic acid methoxy-methyl-amide

Lösungsmittel

ethyl acetate

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeThe volatiles are removed in vacuo and toluene (20 mL)
2. 2
   workup.ADDITIONis added
3. 3
   SonstigeThe toluene is then removed in vacuo
4. 4
   workup.DISSOLUTIONTo the resultant crude oil is dissolve in dichloromethane (100 mL)
5. 5
   TrocknenThe organic layer is dried over anhydrous magnesium sulfate
6. 6
   Filtrationfiltered
7. 7
   Einengenconcentrated in vacuo
8. 8
   SonstigeThe product is purified over silica eluting with 8:2 hexanes

Vorschrift

To a solution of 2-(4-Trifluoromethyl-benzoylamino)-propionic acid (5.0 g, 19.14 mmol) is added oxalyl chloride (16.7 mL, 191.4 mmol) and 2 drops of DMF and the solution stirred overnight. The volatiles are removed in vacuo and toluene (20 mL) is added. The toluene is then removed in vacuo. To the resultant crude oil is dissolve in dichloromethane (100 mL), cooled to 0° C. and triethylamine (13.4 mL, 96 mmol) is added followed by N,O-dimethyl hydroxylamine hydrochloride (9.4 g, 96 mmol). After 1 hr the mixture is partioned between 1M aqueous hydrochloric acid and ethyl acetate. The organic layer is dried over anhydrous magnesium sulfate, filtered, concentrated in vacuo. The product is purified over silica eluting with 8:2 hexanes:ethyl acetate to afford 4-methyl-2-(4-trifluoromethyl-phenyl)-oxazole-5-carboxylic acid methoxy-methyl-amide as a white crystalline solid, 2.4 g, 40%. MS (M++1) 315.

Quelle