For the action of iodine and silver acetate on flavanones to take place, the nature and position of substituents are important. The presence of either a 5-hydroxyl or a 5-methoxyl is essential for any reaction to occur. A free hydroxyl in the 7-position is inhibitory even for iodination of 5-hydroxyflavanone derivatives. Complete methyl ethers yield 8-iodocompounds; whereas 5-hydroxy-7-methoxyflavanones afford a mixture of 3-iodo and 8-iodo derivatives. Simple 5-hydroxy-flavanone forms 3, 8-di-iodo and 2, 3-di-iodo-5-hydroxy flavanones. 5-Hydroxy-7, 4′-diacetoxy-flavanone undergoes iodination only in the pyranone part to yield 2, 3-di-iodo and 3-iodo derivatives; substitution in the benzene ring is inhibited. It is suggested that the 5-hydroxyl by chelation with the carbonyl increases the activity of the methylene group in the 3-position.