N-Methoxy-N-methylbenzamide → Imidazo[1,5-a]pyrazine-1,7(8h)-dicarboxylic acid,3-benzoyl-5,6-dihydro-,7-(1,1-dimethylethyl)ester

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Reaction Conditions

Reaction Steps

Under a nitrogen atmosphere Compound 11 (0.15 g, 0.43 mmol) was dissolved in THF (2 mL) and N-methoxy-N-methylbenzamide (0.14 g, 0.86 mmol) was added. The resulting solution was cooled to −78° C. and tert-Butyl lithium (1.7M in THF, 1.02 mL, 1.73 mmol) was added dropwise. The resulting mixture was stirred and cooled for 1 h and quenched with NH4Cl saturated solution. The solid was removed by filtration and the filtrate was concentrated, acidified to pH 6 with 5% TFA and extracted with 20% i-PrOH/DCM. The organic layer was concentrated, diluted with DCM, washed with brine, dried over anhydrous Na2SO4, filtered and concentrated to give product 25A (0.072 g, 45%). LCMS (+ESI) m/z 372.1 [M+H]+.

Provenance & Evidence