반응 #6436

반응 방정식

4-(acetyloxy)-2,2,6,6-tetramethyl 3,5 heptanedione

ammonium acetate

→

1-[4-(1,1-dimethylethyl)-2-methyl 5-oxazolyl]-2,2- dimethyl-1-propanone

수율 92.5%

용매

acetic acid

water

sodium hydroxide

반응 조건

후처리

1. 1
   온도The reaction mixture is heated
2. 2
   온도at reflux overnight
3. 3
   추출The product is extracted into ethyl acetate (3×150 mL)
4. 4
   세척the combined organic layers are washed with 0.1N NaOH, water
5. 5
   기타The organic layer is dried
6. 6
   기타evaporated
7. 7
   세척The silica pad is eluted with hexane (100 mL)
8. 8
   세척Then the product is eluted from the silica with hexane/ethyl acetate (4:1)

실험 절차

A solution of 4-(acetyloxy)-2,2,6,6-tetramethyl 3,5 heptanedione (22 g, 0.09 mol) in acetic acid (100 mL) is treated with ammonium acetate (44 g). The reaction mixture is heated at reflux overnight. The reaction mixture is diluted with water and neutralized (to pH 5) by the addition of aqueous sodium hydroxide. The product is extracted into ethyl acetate (3×150 mL) and the combined organic layers are washed with 0.1N NaOH, water, and then brine. The organic layer is dried and evaporated. The residue is taken up in hexane (50 mL) and applied to a pad of silica gel (500 g). The silica pad is eluted with hexane (100 mL). Then the product is eluted from the silica with hexane/ethyl acetate (4:1) to give 18.6 g (91%) of 1-[4-(1,1-dimethylethyl)-2-methyl 5-oxazolyl]-2,2- dimethyl-1-propanone as an oil.

출처