Isoamyl Nitrite → 5-Bromo-6-(4-chloro-phenyl)-3-trifluoromethyl-pyrazine-2-carboxylic acid methyl ester

Participants

Reaction Conditions

Reaction Steps

To a suspension of 2.11 g 5-amino-6-(4-chloro-phenyl)-3-trifluoromethyl-pyrazine-2-carboxylic acid methyl ester in 20 ml dibromomethane was added 1.59 g isoamylnitrite and the mixture was cooled to 0° C. To the resulting suspension was added 2.922 g trimethylbromosilane and the mixture was stirred at 0° C. for 10 min (no conversion by HPLC) and at room temperature for 3 h. To the dark reaction mixture was added another 1.59 g isoamylnitrite and the mixture was stirred at room temperature for 6 h. The dark reaction mixture was pored onto ice and ca 20 ml 10% sodium bicarbonate and the product was extracted with dichloromethane (2.64 g raw material which crystallized) and purified by chromatography on silica gel (20 g hep:EE=9:1 to 1:1) to yield 2.290 g of the title compound as white crystals. MS (M+H at 396.8 and 394.9).

Provenance & Evidence