✍ Scribed by Hans-Joachim Winckelmann; Erika Smakula; Herbert H. Wotiz
No coin nor oath required. For personal study only.
The rea ction product of estradiol-17P ' with N vbromosu ocinimide in the dark and under reflux in carbon tetrachloride was determined by infrared investigation as a mixture of 2-and 4-monobromo-and 2:4-dibromoestradiols in y ields of approximately 50, 45 and 5 per cent, re spectively. Infrared referen ce spectra of the three o-bromoe stradiols are given , and the influence of the specific type of bromine substitution on the aromatic vibrations of ring A is discussed. The expected trans-cis isomerism of the phenolic O-H group was investigated by hydrogen bond st udies. As a new phenomenon observed in connect ion with o-substituted compounds it wa s foun d that a change in the molecular geometry of the a-bromo position is asso ciated with a change in the trans-cis ratio and t he ~v v alue of the phenoli c hydroxyl group, whi ch appears t o b e due to a variation of t he elect ronegat ivity of the bromine atom and to a v ariation of double bond character of the aromatic C-Br bond. Th e trane-cis ratio was de t ermined as 1 : 33 for 2-bromoestradiol an d as 1: 15 for 4-bromoestradiol.
• These studies h ave been su pp orted by a research gr ant fr om t he National Can cer Institute, National
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