α, α, α-Tribromoacetophenone derivatives are well synthesized with reference to the method in USP 3, 121, 633 and the literature by Krönke.
We are very much interested in the spectroscopic shifts occuring with the bromination of acetophenone.
Some spectroscopic shifts and their explanations are as follow;
1. 16-20 cm
-1 shift of carbonyl stretching frequency to higher wavenumber is observed when α-position of the ketone is substituted by a bromine atom. In this case, no change of proton magnetic resonance shift with the benzene ring proton is observed.
2. In the solution of mono- and di-bromine substituted ketone, a couple of carbonyl stretching bands and bromine linkage bands are shown. These phenomena are well explained by the existence of two stable rotational isomers at room temperature. More stable and more polar structure of the isomers is discussed.
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