полукетализация

The bromination of condensed chromen-2-ones is carried out. The influence of medium on the reaction occurrence has been studied. In the acidic acid solution aromatization of the 4H-pyrane fragment or hydrogen atom substitution at the tertiary carbon atom takes place. In chloroform, addi­ tion of bromine by the double bond occurs. Mixture of tetrachloromethane and propanol-2 promotes the intermolecular dehydration with the formation of ether bond.