1,2-Dimethoxyethane → Ethyl 8-[(2-fluorobenzyl)oxy]-2-methylimidazo[1,2-a]pyridine-3-carboxylate

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Reaction Steps

A mixture of 25.0 g of 2-amino-3-(2-fluorobenzyloxy)pyridine, 20.5 g ethyl 2-chloroacetoacetate, 10.0 g of sodium bicarbonate and 250 ml dimethoxyethane was heated under reflux for 48 hrs. An additional 5.0 g ethyl 2-chloroacetonacetate was added and refluxed for another 24 hrs., followed by another 5.0 g and refluxed for a further 66 hrs. The mixture was cooled and suctionfiltered. The solids collected were washed with tetrahydrofuran, and the combined filtrate and washings were evaporated invacuo to leave a dark-colored oil. Hexane (200 ml) was added to the oil with vigorous stirring, and the resulting precipitate filtered off. To this solid was added (with vigorous stirring) acetonitrile (50 ml) and diisopropyl ether (200 ml) and stirring was continued for 0.5 hr. The suspended solid was filtered and crystallized from acetonitrile to give the desired ester.

Provenance & Evidence