Reaktion #155846

Reaktionsgleichung

Indium

HCl

2-bromo-7-nitro-5-trityl-pyrrolo[2,3-b]pyrazine

indium

→

2-bromo-5-trityl-pyrrolo[2,3-b]pyrazin-7-amine

Lösungsmittel

tetrahydrofuran

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigethen precipitates out over 5 minutes
2. 2
   SonstigeReaction mixture
3. 3
   Filtrationis filtered through celite
4. 4
   Waschenwashing with EtOAc
5. 5
   workup.ADDITIONFiltrate basified by careful addition of NaHCO3
6. 6
   FiltrationEmulsion forms and mixture is filtered again before layers
7. 7
   Sonstigeseparated
8. 8
   ExtraktionAqueous is extracted with EtOAc
9. 9
   SonstigeCombined organics dried
10. 10
    Einengenconcentrated in vacuo to a black foam
11. 11
    Sonstigepurified by chromatography
12. 12
    Wascheneluting with 0-50% EtOAc—petroleum ether)
13. 13
    SonstigeProduct obtained as a green/brown foam
14. 14
    SonstigeDried on high vacuum
15. 15
    Sonstigetaken directly on to acylation reaction

Vorschrift

2-bromo-7-nitro-5-trityl-pyrrolo[2,3-b]pyrazine (5 g, 10.30 mmol) dissolved in tetrahydrofuran (200.0 mL)/water (50.00 mL) and indium (11.83 g, 103.0 mmol) then HCl (20.60 mL of 6 M, 123.6 mmol) added. Indium dissolves then precipitates out over 5 minutes. Reaction mixture is filtered through celite, washing with EtOAc. Filtrate basified by careful addition of NaHCO3. Emulsion forms and mixture is filtered again before layers separated. Aqueous is extracted with EtOAc. Combined organics dried and concentrated in vacuo to a black foam. Residue is taken up in DCM and purified by chromatography eluting with 0-50% EtOAc—petroleum ether). Product obtained as a green/brown foam. Dried on high vacuum and taken directly on to acylation reaction. (3.43 g, 73%). 1H NMR (400.0 MHz, DMSO) δ 8.46 (s, 1H), 8.40 (s, 1H), 7.38-7.36 (m, H), 7.23-7.20 (m, 8H) and 3.32 (s, 7H) ppm; MS (ES+) 457.0

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