Реакция #1135823

Уравнение реакции

Acetic acid 3-(4-hydroxy-phenyl)-8-methyl-4-oxo-4H-chromen-7-yl ester

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Acetic acid 3-(4-hydroxy-phenyl)-8-methyl-4-oxo-chroman-7-yl ester

Растворители

ethyl acetate

Условия реакции

Обработка

1. 1
   Другоеevacuated
2. 2
   Другоеpurged with nitrogen gas (×5) and hydrogen gas (×5)
3. 3
   workup.ADDITION10% Pd/Al2O3 (9 g, 35%) was added to the round bottom flask at 40 hours
4. 4
   workup.ADDITION10% Pd/Al2O3 (5.69 g, 20%) was added to the round bottom flask
5. 5
   Другоеreaction rate
6. 6
   ДругоеReaction
7. 7
   workup.WAITwas completed at 64 hours
8. 8
   ФильтрацияThe reaction mixture was filtered through celite
9. 9
   Другоеto remove the Pd/Al2O3 catalyst
10. 10
    Промывкаthe celite was rinsed with EtOAc (1 L)
11. 11
    Другоеwas collected
12. 12
    ДругоеThe EtOAc was evaporated off on a rotary evaporator
13. 13
    Другоеto give a yellow solid
14. 14
    ДругоеThe solid was re-crystallised in 95% EtOH (650 ml)
15. 15
    workup.WAITleft in the freezer overnight
16. 16
    ФильтрацияOff-white crystals were collected by suction filtration
17. 17
    workup.WAITThe crystals were stored in a desiccator for 24 hours

Методика

Acetic acid 3-(4-hydroxy-phenyl)-8-methyl-4-oxo-4H-chromen-7-yl ester (26.32 g), 10% Pd/Al2O3 (12.93 g, 50%) and ethyl acetate (EtOAc) (1.5 L) were added to a hydrogenation round bottom flask (2 L). The flask was placed on the hydrogenator, evacuated, purged with nitrogen gas (×5) and hydrogen gas (×5). The reaction was monitored by HPLC. 10% Pd/Al2O3 (9 g, 35%) was added to the round bottom flask at 40 hours, indicated there was no product peak present, only starting material was present. HPLC at 62 hours indicated that the major peak was product peak with starting material peak being half height of product peak. 10% Pd/Al2O3 (5.69 g, 20%) was added to the round bottom flask to speed up reaction rate. Reaction was completed at 64 hours. The reaction mixture was filtered through celite to remove the Pd/Al2O3 catalyst, the celite was rinsed with EtOAc (1 L) to ensure majority of product was collected. The EtOAc was evaporated off on a rotary evaporator to give a yellow solid. The solid was re-crystallised in 95% EtOH (650 ml) and left in the freezer overnight. Off-white crystals were collected by suction filtration. 1HNMR in d-CDCl3 indicated the off-white crystals were 8Acetic acid 3-(4-hydroxy-phenyl)-8-methyl-4-oxo-chroman-7-yl ester with >95% purity. The crystals were stored in a desiccator for 24 hours, and weighed (18.37 g, 69%).

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