Hydrochloric Acid → 2-Bromo-5-trityl-pyrrolo[2,3-b]pyrazin-7-amine

Participants

Reaction Steps

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

Provenance & Evidence