Potassium Sodium Tartrate → 1-Oxo-3-(4-trifluoromethyl-phenyl)-1,2-dihydro-pyrrolo[1,2-a]pyrazine-6-carbaldehyde

Participants

Reaction Conditions

Reaction Steps

A mixture of 1-oxo-3-(4-trifluoromethyl-phenyl)-1,2-dihydro-pyrrolo[1,2-a]pyrazine-6-carbonitrile (Example 2) (55 mg, 0.18 mmol) in methylene chloride (1 mL) cooled −75° C. was treated dropwise with 1M diisobutylaluminum hydride in methylene chloride (275 μL, 0.27 mmol). The reaction was stirred at −75° C. for 1.5 h. At this time, the reaction was treated with additional 1M diisobutylaluminum hydride in methylene chloride (0.1 mL, 0.1 mmol) and allowed to stir at −75° C. for an additional 1 h. At this time, the reaction was treated with a solution of Rochelle's salt, and the mixture was allowed to warm up to room temperature where it stirred overnight. At this time, the resulting suspension was absorbed onto silica gel. Flash chromatography (4 g silica column, 0-50% ethyl acetate/hexanes) afforded 1-oxo-3-(4-trifluoromethyl-phenyl)-1,2-dihydro-pyrrolo[1,2-a]pyrazine-6-carbaldehyde (22 mg, 40%) as light yellow solid. 1H NMR (acetone-d6) δ ppm 10.02 (s, 1H), 8.11 (d, J=1.5 Hz, 1H), 8.03 (d, J=8.0 Hz, 2H), 7.89 (d, J=8.5 Hz, 2H), 7.85 (s, 1H), 7.42 (s, 1H). LC-MS calcd. for C15H10F3N2O2 [(M+H)+] 307, obsd. 306.8.

Provenance & Evidence