1, 4, 4tribromocyclopentene3, 5-dione. Addition of the dione to a solution of bromine in aqueous sodium bicarbonate furnished 4, 4-dibromocyclopenten~, 5-dione in satisfactory yields. The enedione also reacted smoothly with ethyl alcohol in the presence of boron trifluoride to form 3, 4diethoxycyclopent-2enone. Thia compound could be reduced and hydrolyzed to 5-ethoxycyclopent-2-enone.
