2,4,6-Trimethylpyridine → HCID 135666683, compound

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Reaction Steps

C-4. 8-Ethyl-2-(4-hydroxyphenyl)pyrido[2,3-d]pyrimidin-5(8H)-one--A mixture containing 2.4 g of 8-ethyl-2-(4-methoxyphenyl)pyrido[2,3-d]pyrimidin-5(8H)-one, 8.1 g of anhydrous lithium iodide, 125 ml of collidine and one drop of dicyclohexyl-12-crown-4 was refluxed with stirring for 24 hours and then allowed to cool to room temperature. The reaction mixture was diluted with n-hexane (900 ml) to complete the precipitation of the product. The oily material that separated solidified on standing at room temperature. The solid was collected, washed with n-hexane and then dissolved in water. The water solution and washed with ether, acidified with hydrochloric acid and the resulting mixture was slurried, treated with an excess of sodium bicarbonate and again slurried. The solid was collected, washed with water and dried at 65° C. in vacuo to yield 1.85 g of 8-ethyl-2-(4-hydroxyphenyl)pyrido[2,3-d]pyrimidin-5(8H)-one, m.p. 320°-324° C. This product was combined with 12 g of product obtained in five other runs and the combined material was suspended in about 350 ml of boiling ethanol after which dimethylformamide was added portionwise until dissolution was complete. The hot solution was treated with decolorizing charcoal, filtered, and the filtrate cooled. The separated product was collected, washed with cold ethanol and dried in vacuo at 60° C. to produce 2.6 g of 8-ethyl-2-(4-hydroxyphenyl)pyrido[2,3-d]pyrimidin-5(8H)-one, m.p. 323°-325° C. The filtrate was stripped in vacuo, the solid residue was recrystallized from ethanoldimethylformamide to yield another 0.8 g of product, 8-ethyl-2-(4-hydroxyphenyl)pyrido[2,3-d]pyrimidin-5(8H)-one, m.p. 321°-322° C.

Provenance & Evidence