The regioselective ring opening halogenation of some epoxides using elemental iodine and bromine in the presence of a series of pyridine-containing groups has been studied. The epoxides were subject to cleavage by elemental halogen (I2 and Br2) in the presence of isonicotinic hydrazide (isoniazide) under mild reaction conditions in various solvents. In this study, reagents and conditions have been discovered with which the individual halohydrins can be synthesized in high yield and with more than 95% regioselectivity.
