HCID 67916524, compound → 2-methyl-1H-1,5-naphthyridin-4-one

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Reaction Steps

Ethyl-(Z)-3-(3-pyridylamino)-2-butenoate (8.0 g) (obtained as described in J. Royal Netherlands Chem. Soc., 1976, 95, 220) was added to a refluxing eutectic mixture of 26.5% v/v diphenyl and 73.5% v/v diphenyl oxide (20 ml). The solution was heated under reflux for 1 hour and then cooled. The precipitated solid was collected, washed with hexane (20 ml) and ether (20 ml), and then purified by flash chromatography, eluting initially with methanol/dichloromethane (1:4 v/v). There was thus obtained 2-methyl-1,7-naphthyridin-4-(1H)-one (0.96 g), as an off-white powder, m.p. >250° C. (sublimes); NMR (d6 -DMSO): 2.4(s,3H), 6.2(s,1H), 8.1(d,1H), 8.45(d,1H), 9.0(s,1H). Further elution of the chromatography column with aqueous ammonia/methanol/dichloromethane (2:99:99 v/v) gave the required 2-methyl-1,5-naphthyridin-4(1H)-one (D1) (2.25 g), as an off-white powder, m.p. >280° C. (decomp.); NMR: 2.65(s,3H), 6.65(s,1H), 7.6(dd,1H), 8.4(dd,1H), 8.8(dd,1H).

Provenance & Evidence