반응 #68827

반응 방정식

sulfuric acid

4-[5-(1,4-dioxa-8-aza-spiro[4.5]dec-8-yl)-pyridin-2-yl]-3,4-dihydro-2H-quinoxaline-1-carboxylic acid

intermediate 7.1

4-[5-(1,4-dioxa-8-aza-spiro[4.5]dec-8-yl)-pyridin-2-yl]-3,4-dihydro-2H-quinoxaline-1-carboxylic acid

sodium hydroxide

→

6′-(3,4-dihydro-2H-quinoxalin-1-yl)-2,3,5,6-tetrahydro-[1,3′]bipyridinyl-4-one

용매

water

acetone

water

tetrahydrofuran

반응 조건

후처리

1. 1
   온도It is cooled on an ice bath
2. 2
   추출is extracted twice with ethyl acetate
3. 3
   세척The combined organic phases are washed with water
4. 4
   건조dried over sodium sulfate
5. 5
   여과filtered
6. 6
   기타evaporated to dryness
7. 7
   기타The raw product obtained
8. 8
   기타is chromatographed on silica gel
9. 9
   세척eluting with a gradient of ternary solvents, on the one hand heptane and on the other hand heptane/ethyl acetate/methanol 4/5/1 varying from 10% to 100%

실험 절차

In a 150-ml flask, 5.51 g of tert-butyl ester of 4-[5-(1,4-dioxa-8-aza-spiro[4.5]dec-8-yl)-pyridin-2-yl]-3,4-dihydro-2H-quinoxaline-1-carboxylic acid (intermediate 7.1) is put in 21 ml of tetrahydrofuran, 21 ml of water and 20 ml of acetone. It is cooled on an ice bath and 8.24 ml of 95% sulfuric acid is added gently. It is stirred at room temperature for 18 h. The solution is then poured into water. 5N sodium hydroxide is added to basic pH and it is extracted twice with ethyl acetate. The combined organic phases are washed with water, dried over sodium sulfate, filtered and evaporated to dryness. The raw product obtained is chromatographed on silica gel, eluting with a gradient of ternary solvents, on the one hand heptane and on the other hand heptane/ethyl acetate/methanol 4/5/1 varying from 10% to 100%. 2.39 g of 6′-(3,4-dihydro-2H-quinoxalin-1-yl)-2,3,5,6-tetrahydro-[1,3′]bipyridinyl-4-one is obtained.

출처