1,8-Diazabicyclo(5.4.0)undec-7-ene → 2-[-2-(5,8-Dimethyl[1,2,4]triazolo[1,5-a]pyrazin-2-yl)-vinyl]-5H-imidazo[2,1-a]isoindole

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Reaction Steps

A solution of 5H-imidazo[2,1-a]isoindole-2-carbaldehyde (150 mg, 0.81 mmol) in dry THF (5.3 mL) was added to (5,8-Dimethyl-[1,2,4]triazolo[1,5-a]pyrazin-2-ylmethyl)-triphenyl-phosphonium chloride (374 mg, 0.81 mmol) under argon and 1,8-diazabicyclo[5.4.0]undec-7-ene (120 micro L, 0.81 mmol) was added. The reaction mixture was stirred at room temperature for 12 hours after which it was evaporated onto silica gel (2 g). Silica gel chromatography (gradient elution; A:B 100:0 to 0:100, where A is ethyl acetate and 8 is 10% MeOH in ethyl acetate) afforded the title compound as a mixture of the cis and trans isomers (139 mg, 52%). LC-MS: m/z=329.3 (MH+), tR=0.96 minutes.

Provenance & Evidence