반응 #95590

반응 방정식

5,6-dihydro-5-methyl-6-oxo-4H-imidazo[1,5-a][1,4]benzodiazepine-3-carboxaldehyde

magnesium

magnesium

ethyl iodide

→

4,5-dihydro-3-(1-hydroxypropyl)-5-methyl-6H-imidazo[1,5-a][1,4]benzodiazepin-6-one

용매

tetrahydrofuran

diethyl ether

diethyl ether

반응 조건

후처리

1. 1
   기타When the Grignard reaction
2. 2
   workup.ADDITIONthe mixture is treated dropwise with a solution
3. 3
   온도is heated
4. 4
   온도under reflux for ca 5.5 hours
5. 5
   여과The mixture is filtered over Dicalit
6. 6
   세척while rinsing with tetrahydrofuran
7. 7
   세척The chloroform phase is washed twice with 60 ml of water each time
8. 8
   건조dried over magnesium sulphate
9. 9
   농축concentrated
10. 10
    기타The crude product is chromatographed on silica gel
11. 11
    세척for the elution
12. 12
    기타After recrystallisation from ca 40 ml of ethyl acetate

실험 절차

1.22 g (50.2 mmol) of magnesium shavings are covered with 60 ml of absolute diethyl ether under an argon atmosphere and treated with 2-3 drops of ethyl iodide. When the Grignard reaction starts, a solution of 4.3 ml (51 mmol) of ethyl iodide in 10 ml of absolute diethyl ether is added dropwise at the boiling point. After the magnesium has dissolved completely, the mixture is treated dropwise with a solution, warmed to 30° C., of 0.65 g (40 mmol) of 5,6-dihydro-5-methyl-6-oxo-4H-imidazo[1,5-a][1,4]benzodiazepine-3-carboxaldehyde in 200 ml of absolute tetrahydrofuran. The yellow coloured suspension is heated to boiling under reflux for ca 5.5 hours, cooled to room temperature and poured into 600 ml of ice/water. The mixture is filtered over Dicalit while rinsing with tetrahydrofuran. After concentration of the filtrate in vacuo, the residue is taken up in 250 ml of chloroform. The chloroform phase is washed twice with 60 ml of water each time, dried over magnesium sulphate and concentrated. The crude product is chromatographed on silica gel using chloroform/methanol (19:1, vol/vol) for the elution. After recrystallisation from ca 40 ml of ethyl acetate, there is obtained 4,5-dihydro-3-(1-hydroxypropyl)-5-methyl-6H-imidazo[1,5-a][1,4]benzodiazepin-6-one of melting point 145°-147° C.

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