Reaktion #6869

Reaktionsgleichung

product

7-((1,1-Dimethylethoxy)carbonyl)-8-(2-hydroxyethyl)-2-(2-methoxyphenyl)-5,6,7,8-tetrahydro-imidazo[1,2-a]pyrazine

Diethylazodicarboxylate

Triphenylphosphine

triphenylmethanethiol

→

foam

Ausbeute 111.0%

7-((1,1-Dimethylethoxy)carbonyl)-2-(2-methoxyphenyl)-5,6,7,8-tetrahydro-8-(2-((triphenylmethyl)thio)ethyl)-imidazo[1,2-a]pyrazine

Ausbeute 111.0%

Lösungsmittel

THF

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturwas maintained at about <3° C
2. 2
   workup.STIRRINGThe resulting mixture was stirred for about 1 hour at about 0° C.
3. 3
   Sonstigeto warn to room temperature
4. 4
   EinengenThe mixture was concentrated under reduced pressure
5. 5
   workup.DISSOLUTIONthe residue dissolved in ether (40 ml)
6. 6
   workup.WAITto stand overnight
7. 7
   FiltrationThe solid was filtered off
8. 8
   Einengenthe filtrate was concentrated
9. 9
   Sonstigethen purified by flash chromatography on silica gel using 4:1/hexanes
10. 10
    Einengenconcentrated under reduced pressure

Vorschrift

Triphenylphosphine (4.08 g, 15.5 mmol) was dissolved in THF (25 ml), cooled to about 0° C. under N2 and Diethylazodicarboxylate (2.45 ml, 15.54 mmol) was added at a dropwise rate so that the reaction temperature was maintained at about <3° C. Stirring was continued for about ½ hour at 0° C. A mixture of the triphenylmethanethiol (4.30 g, 15.54 mmol) and the product from Step 13.e. (2.90 g, 7.77 mmol) in THF (25 ml) was added at a dropwise rate. The resulting mixture was stirred for about 1 hour at about 0° C. and then allowed to warn to room temperature. The mixture was concentrated under reduced pressure and the residue dissolved in ether (40 ml) and allowed to stand overnight. The solid was filtered off and the filtrate was concentrated then purified by flash chromatography on silica gel using 4:1/hexanes:EtOAc and then 4:1/hexanes:EtOAc as eluants. The product fractions were combined and concentrated under reduced pressure to obtain a pale yellow foam (5.49 g, 111%) which was used without further purification. Mass spec. 632.4 MH+.

Quelle