反应详情

6.95 g of 2,2-dimethyl-4-(2-pyridyl)-2H-1-benzopyran were dissolved in 100 ml of ethanol and shaken at room temperature with 10% palladium-on-charcoal under a hydrogen atmosphere. After the required volume of hydrogen had been taken up the catalyst was filtered off, the filtrate was evaporated and the residue was recrystallized from n-hexane to give 5.07 g of 3,4-dihydro-2,2-dimethyl-4-(2-pyridyl)-2H-1-benzopyran of melting point 99°-101° C.

1. filtrationwas filtered off
2. customthe filtrate was evaporated
3. customthe residue was recrystallized from n-hexane