Water → HCID 19771712, compound

Participants

Reaction Steps

A solution of 5-amino-2-methoxypyridine (50 g), methyl propionylacetate (57.3 g) and p-toluenesulphonic acid (0.5 g) in benzene (200 ml) was heated under reflux with azeotropic removal of water for 20 hours. Volatile material was removed by evaporation and the residue added to a refluxing eutectic mixture of 26.5% v/v diphenyl and 73.5% v/v diphenyl oxide (140 ml). The solution was heated under reflux for 1 hour, cooled and diluted with hexane (500 ml). The precipitated solid was filtered off and triturated with hot methanol (500 ml) to give 2-ethyl-6-methoxy-1,5-naphthyridine-4 (1H)-one (B4) (32.3 g), as a pale brown solid, m.p. 279°-281° C.; NMR (d6 -DMSO): 1.2 (t, 3H), 2.65 (q, 2H), 3.95 (s, 3H), 6.3 (br s, 1H), 7.15 (d, 1H), 7.95 (d, 1H).

Provenance & Evidence