Methanol → HCID 57743074, compound

Participants

Reaction Conditions

Reaction Steps

Ethyl 2-[(4-methoxybenzyl)amino]-3-nitro-6-(trifluoromethyl)isonicotinate x193 (2.6 g, 6.5 mmol) is dissolved in methanol (100 ml), and Raney nickel (0.8 g) is added. The starting compound is hydrogenated in a Parr apparatus under a hydrogen pressure of 3 atm until the conversion of x193 is complete (1.5-2 h). The catalyst is filtered off and washed with methanol. The filtrate is evaporated to dryness. Triethyl orthoformate (100 ml) and p-toluene sulfonic acid (0.15 g) are added. The flask is equipped with a reflux condenser. The apparatus is flushed with argon, and the obtained reaction mixture is heated under vigorous stirring to 150° C. for 6 h. The reaction solution is evaporated in vacuum. The residue is partitioned between dichloromethane and a saturated aqueous solution of NaHCO3. The organic layer is dried with anhydrous sodium sulfate and evaporated. The target product is purified by chromatography on silicagel (dichloromethane/acetone) to afford 1.5 g of ethyl 3-(4-methoxybenzyl)-5-(trifluoromethyl)-3H-imidazo[4,5-b]pyridine-7-carboxylate x196.

Provenance & Evidence