Reaktion #709030

Reaktionsgleichung

2-chloro-3-nitropyridine

(S)-alanine ethyl ester hydrochloride

triethylamine

→

title compound

Ausbeute 0.1%

(S)-N-(3-Nitro-2-pyridinyl)alanine hydrochloride

Ausbeute 0.1%

Lösungsmittel

ethanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturwas heated
2. 2
   Temperaturat reflux for 4.5 hours, during which time a dark yellow solution
3. 3
   Sonstigeformed
4. 4
   Temperaturrefluxed for an additional 2 hours
5. 5
   SonstigeThe solvents were evaporated under reduced pressure
6. 6
   Sonstigethe resulting solid was triturated in ethyl acetate
7. 7
   Filtrationfiltered
8. 8
   Waschenrinsed with additional ethyl acetate
9. 9
   Waschenwashed three times with water
10. 10
    Trocknendried over sodium sulfate
11. 11
    Filtrationfiltered
12. 12
    Sonstigeevaporated to an oil
13. 13
    WaschenThe oil was eluted through 600 g of silica gel
14. 14
    Sonstigeevaporated to an oil
15. 15
    workup.DISSOLUTIONA 3.5-g portion of the oil was dissolved in isopropyl alcohol
16. 16
    SonstigeThe mixture was evaporated
17. 17
    workup.DISSOLUTIONredissolved in acetonitrile
18. 18
    workup.ADDITIONAddition of isopropyl ether
19. 19
    Sonstigeto precipitate
20. 20
    FiltrationThe solid was collected by filtration and its mother liquor
21. 21
    Sonstigewas evaporated
22. 22
    Sonstigethe residue was triturated in ethereal hydrogen chloride
23. 23
    SonstigeA yellow solid formed which
24. 24
    Filtrationwas collected by filtration
25. 25
    Sonstigemore solid formed in the mothor liquor
26. 26
    FiltrationThis solid was collected by filtration
27. 27
    Waschenrinsed with diethyl ether
28. 28
    Sonstigedried under high vacuum

Vorschrift

A suspension of 2-chloro-3-nitropyridine (68.6 g, 0.434 mole), (S)-alanine ethyl ester hydrochloride (100 g, 0.651 mole) and triethylamine (103.7 g, 1.03 mole) in 95% ethanol was heated at reflux for 4.5 hours, during which time a dark yellow solution formed. The reaction mixture was stirred at room temperature overnight and then refluxed for an additional 2 hours. The solvents were evaporated under reduced pressure, and the resulting solid was triturated in ethyl acetate, filtered, and rinsed with additional ethyl acetate. The filtrate and washings were combined and washed three times with water, dried over sodium sulfate, filtered, and evaporated to an oil weighing 107 g (quantitative yield). The oil was eluted through 600 g of silica gel, using ethyl acetate as the eluent, and evaporated to an oil. A 3.5-g portion of the oil was dissolved in isopropyl alcohol and acidified with ethereal hydrogen chloride. The mixture was evaporated and redissolved in acetonitrile. Addition of isopropyl ether caused a solid to precipitate. The solid was collected by filtration and its mother liquor was evaporated and the residue was triturated in ethereal hydrogen chloride. A yellow solid formed which was collected by filtration. Upon standing, more solid formed in the mothor liquor. This solid was collected by filtration, rinsed with diethyl ether and dried under high vacuum to give 0.14 g of title compound, mp >260° C. (darkens 178°-185° C.).

Quelle