Water → 3,5-Dibromo-2-chloropyrazine

To a solution of 3,5-dibromopyrazin-2-amine (234 g, 932 mmol) in DCM (700 mL) and titanium (IV) chloride (174 g, 926 mmol), tert-butyl nitrite (572 g, 5.55 mol) was slowly added. The resulting mixture was stirred for 2 h at room temperature and treated with water (500 mL). The resulting mixture was extracted with DCM (3×500 mL). The combined organic layers were concentrated under reduced pressure. The resultant residue was purified by flash column chromatography on silica gel (EtOAc/petroleum ether (1:50 v/v)) to obtain compound 90d as colorless oil (210 g, 83% yield). Mass Spectrum (LCMS, ESI pos.): Calcd. for C4HBr2ClN2: 272.8 (M+H). found 272.6.

1. extractionThe resulting mixture was extracted with DCM (3×500 mL)
2. concentrationThe combined organic layers were concentrated under reduced pressure
3. customThe resultant residue was purified by flash column chromatography on silica gel (EtOAc/petroleum ether (1:50 v/v))

ORD-Eintrag

ord-3f4bd868aacc43ba8700f1d1620da676

Quelldatensatz

uspto-grants-2016_02

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US09249163B2