Studies on quinoline derivatives and related compounds. III. A novel pyridine synthesis to give substituted 1,4‐dihydro‐4‐oxonicotinic acids

Abstract

A variety of 5‐mono‐ and 5,6‐disubstituted 1,4‐dihydro‐4‐oxonicotinates were prepared by a novel pyridine synthesis which involves thermal cyclisation of enaminomethylenemalonates 9. The intermediates 9 were readily prepared through a few steps from commercially available starting materials.

The Chemistry of the Quinolones: Methods of Synthesizing the Quinolone Ring System

“…The starting compounds 187 are produced in a relatively simple manner either by condensation of the respective primary enamines with ethoxymethylene malonic esters or condensation of the relevant ketones with aminomethylene malonic esters (AGUI et al 1975b). …”