1,6-Naphthyridine → 5,6,7,8-Tetrahydro-6-(5-hexanonyl)-1,6-naphthyridine

Beteiligte Stoffe

Reaktionsschritte

A solution of 1,6-naphthyridine (13.0 g, 0.1 mol) and 6-bromohexan-2-one ethylene ketal (26.8 g, 0.12 mol) in acetonitrile (100 ml) was refluxed for 10 hours. The reaction mixture was evaporated in vacuo, dissolved in methanol (600 ml) and water (200 ml). To the mixture, sodium borohydride (19.5 g, 0.5 mol) was added portionwise over the internal temperature range 0° to 20° C. After stirring overnight at room temperature, the reaction mixture was evaporated in vacuo, water added and extracted with ethyl acetate. The organic layer was dried over anhydrous potassium carbonate, evaporated in vacuo. The resulting residue was dissolved in 1 N-HCl and stirred overnight, neutralized with 33% NaOH solution and extracted with chloroform. The organic layer was dried over anhydrous potassium carbonate, evaporated in vacuo. The residue was purified by alumina column chromatography (eluted with chloroform-methanol (10:1)) and distilled, bp. 157°-158° C./0.6 mmHg, to afford the Compound No. 29 (9.3 g, 40.1%) as a light yellow oil.

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