HCID 68120050, compound → HCID 21395290, compound

Participants

Reaction Steps

The hydrogenation of 3-(3-hydroxy-4-methoxycinnamoyl)-6-methyl-2H-pyran-2,4(3H)-dione as prepared in the above step of Claisen-Schmidt condensation was carried out in the following way. The condensation product (1.39 g.) obtained in the above step was dissolved in 150 ml. of dioxane, and the hydrogenation was effected in the presence of 0.1 g. of 5% palladium-charcoal at room temperature and under the atmospheric pressure. One mole equivalent of hydrogen was absorbed in 8 hours. After removal of the catalyst and the solvent, the remaining crystalline product was subjected to silica gel chromatography for purification. Upon recrystallization from a mixed solvent of ethanol and n-hexane, 1.11 g. of 3-(3-hydroxy-4-methoxyhydrocinnamoyl)-6-methyl-2H-pyran-2,4(3H)-dione was obtained, showing mp. 115°-116°C.

Provenance & Evidence