Potassium Carbonate → Methyl 5-(5,6-dimethoxy-3H-imidazo[4,5-b]pyridin-3-yl)-3-{[2-(trifluoromethyl)benzyl]oxy}thiophene-2-carboxylate

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Reaction Steps

To a solution of an isomeric mixture of 1.76 g of methyl 5-(5,6-dimethoxy-1H-imidazo[4,5-b]pyridin-1-yl)-3-hydroxythiophene-2-carboxylate and methyl 5-(5,6-dimethoxy-3H-imidazo[4,5-b]pyridin-3-yl)-3-hydroxythiophene-2-carboxylate (example C7) in 20 ml anhydrous N,N-dimethylformamide were added 0.86 g K2CO3 and 1.51 g of 1-(bromomethyl)-2-(trifluoromethyl)benzene under a nitrogen atmosphere. The reaction mixture was stirred for 12 h at room temperature, poured into 200 ml of ice water and stirred for 1 h. The solid was filtered, dissolved in acetonitrile and the isomeric mixture was separated and purified by preparative HPLC to yield compound B4a and compound B4b. The structural assignment of compound B4a was unequivocally established by two-dimensional 1H NMR experiments (NOESY, COSY).

Provenance & Evidence