Nitrogen → 2-ethyl-5,7-dimethyl-3-(4-nitrobenzyl)-3H-imidazo[4,5-b]pyridine

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Reaction Steps

To a solution of 5.0 g (1.0 eq, 28.6 mmol) 5,7-dimethyl-2-ethylimidazo[4,5-b]pyridine in 30 mL DMF under N2 at rt was added 1.37 g (1.2 eq, 34.3 mmol) of a 60% oil dispersion of NaB. After stirring for 5 minutes, 8.64 g (1.4 eq, 40.0 mmol) of p-nitrobenzyl bromide was added. The dark brown mixture was stirred for 2 hours under a blanket of N2 at rt. The mixture was diluted with 1 L CH2Cl2 and washed with 500 mL H2O and 500 mL saturated aqueous NaCl. The organic phase was dried over MgSO4 and concentrated to a yellow oil. The oil was flash chromatographed with 50% ethyl acetate/hexane. The product containing fractions were combined and concentrated to a yellow oil which crystallized on standing, yielding 6.81 g (76.8%) of the title compound.

Provenance & Evidence