Diethyl Ether → HCID 21073853, compound

Participants

Reaction Steps

A sixth intermediate compound, 7-(4-Hydroxy-butoxy)-5-methyl-3,4-dihydro-1H-[1,8]naphthyridin-2-one, was produced as follows: 7-(4-Benzyloxy-butoxy)-5-methyl-1H-[1,8]naphthyridin-2-one (7.31 g, 21.6 mmol) was hydrogenated using 20% Pd/C (1.0 g) in EtOH (100 mL). The product precipitated out of solution before the double bond was reduced. DMF (75 mL) was added and the mixture was heated to dissolve the solids. More 20% Pd/C (1.0 g) was added and the hydrogenation was continued, however the double bond was resistant to further hydrogenation under these conditions. The reaction mixture was filtered and the solvent was concentrated to give a slurry. Et2O was added and the solid was collected by filtration and dried to give 7-(4-hydroxy-butoxy)-5-methyl-1H-[1,8]naphthyridin-2-one (4.37 g, 17.6 mmol, 81%). 7-(4-Hydroxy-butoxy)-5-methyl-1H-[1,8]naphthyridin-2-one (3.0 g, 12.08 mmol) was hydrogenated using 20% Pd/C in acetic acid (mL) for x h. The reaction mixture was filtered and concentrated to give a mixture of the sixth intermediate compound and the corresponding acetylated compound. The mixture was suspended in MeOH (30 mL) and H2O (10 mL) and the pH was adjusted to 14 by addition of 50% aqueous NaOH. The mixture was warmed to 45° C. Glacial acetic acid was added to bring the pH to 7.5 and the MeOH was removed under reduced pressure. The resulting solid was filtered, washed with H2O and dried to give the sixth intermediate compound as a solid (2.78 g, 11.1 mmol, 92%). MS: APCI: M+1: 251.1 (Exact Mass: 250.13).

Provenance & Evidence