Reaktion #323907

Reaktionsgleichung

end product

8-Chloro-5,6-dihydro-4-oxo-6-phenyl-4H-pyrazolo[1,5-a][1,4]benzodiazepine-2-carboxaldehyde

EtOH

hydrazine-hydrate

→

8-Chloro-2-methyl-5,6-dihydro-4-oxo-6-phenyl-4H-pyrazolo[1,5-a][1,4]benzodiazepine

Lösungsmittel

THF hexane

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe reaction was heated
2. 2
   Temperaturto reflux for 17 hours
3. 3
   Temperaturcooled
4. 4
   Einengenconcentrated in vacuo
5. 5
   workup.ADDITIONpotassium t-butoxide added
6. 6
   Temperaturthe mixture heated
7. 7
   Temperaturto reflux for 8 hours
8. 8
   workup.ADDITIONThe reaction was poured over ice and brine and toluene
9. 9
   workup.ADDITIONadded
10. 10
    SonstigeThe toluene phase was separated
11. 11
    Trocknendried over Na2SO4
12. 12
    ExtraktionThe aqueous phase was extracted well with CH2Cl2
13. 13
    Trocknenthe combined extracts dried over Na2SO4
14. 14
    Einengenconcentrated
15. 15
    Sonstigethe crude product recrystallized from THF/hexane
16. 16
    Sonstigeto give the desired end product, mp 258°-261°
17. 17
    Sonstigewas obtained as colorless crystals

Vorschrift

To a solution of 3.43 g. (10.15 mmol) of the end product of Example 15 in 60 ml. of absolute EtOH, was added 12 ml. of hydrazine-hydrate. The reaction was heated to reflux for 17 hours, then cooled and concentrated in vacuo. The residue was taken up in 60 ml. toluene; 1.0 g. potassium t-butoxide added and the mixture heated to reflux for 8 hours, then cooled to room temperature and stirred for 9 hours. The reaction was poured over ice and brine and toluene added. The toluene phase was separated and dried over Na2SO4. The aqueous phase was extracted well with CH2Cl2 and the combined extracts dried over Na2SO4. The dried solutions were combined and concentrated and the crude product recrystallized from THF/hexane to give the desired end product, mp 258°-261°. An analytical sample was prepared by an additional recrystallization from THF/hexane and was obtained as colorless crystals: mp 259°-261°.

Quelle