반응 #45671

반응 방정식

hydrochloric acid

trimethylaluminium

dimethylamine hydrochloride

ethyl 6-bromo-4-cyano-7-fluoro-5-methyl-1,3-benzoxazole-2-carboxylate

→

compound

수율 48.0%

6-Bromo-4-cyano-7-fluoro-N,N,5-trimethyl-1,3-benzoxazole-2-carboxamide

수율 48.0%

용매

dichloromethane

dichloromethane

반응 조건

후처리

1. 1
   온도with cooling in a water bath
2. 2
   workup.STIRRINGstirred for 30 hours
3. 3
   workup.ADDITIONwas added to the reaction liquid
4. 4
   온도with cooling with ice
5. 5
   workup.STIRRINGby stirring at room temperature
6. 6
   기타the reaction liquid
7. 7
   추출was extracted with chloroform
8. 8
   건조dried over anhydrous magnesium sulfate
9. 9
   여과filtered
10. 10
    농축the filtrate was concentrated under reduced pressure

실험 절차

Under nitrogen atmosphere, trimethylaluminium (1.03 M n-hexane solution, 57.9 ml, 59.6 mmol) was dropwise added to a dichloromethane (100 ml) solution of dimethylamine hydrochloride (4.86 g, 59.6 mmol) with cooling in a water bath, taking 30 minutes, and stirred for 65 minutes at room temperature. Subsequently, a dichloromethane (30 ml) solution of ethyl 6-bromo-4-cyano-7-fluoro-5-methyl-1,3-benzoxazole-2-carboxylate (I-126) (6.50 g, 19.9 mmol) was dropwise added and stirred for 30 hours. After the reaction, aqueous 1 N hydrochloric acid solution was added to the reaction liquid with cooling with ice, followed by stirring at room temperature, and the reaction liquid was extracted with chloroform. Next, the obtained organic layers were combined, dried over anhydrous magnesium sulfate, filtered, and the filtrate was concentrated under reduced pressure. The resulting residue was subjected to silica gel column chromatography, and the eluate with dichloromethane/methanol (100:1, v/v) gave the entitled compound (3.10 g, 48%) as a pale yellow solid. The fraction containing impurities was recovered and purified twice in the same manner to obtain the entitled compound (362 mg, 591 mg), and 4.05 g (62%) of the entitled compound was obtained in total.

출처