Wilzbach tritiation studies. I. Isotope distribution in tritium-labelled anthranilic acid, isopropanol and phenyl allyl ether

Abstract

Isotope distribution studies with anthranilic acid labelled by the Wilzbach method indicate that positions 3 and 5 have respectively 49.8% and 27.4% of the total activity, tritium incorporation thus tending to be highest at the most electronegative positions. In isopropanol the hydroxyl group contains approximately three times as much isotope as at any other hydrogen position, while tritiation of the secondary C-H is slightly more efficient than the primary C-H. In the tritiation of phenyl ally1 ether, the predominant process is polymerization after reasonable exposure time, little radiation-induced Claisen rearrangement or saturation of the double bond being observed. A free radical mechanism has been proposed to account for the above distributions which have also been compared with results obtained by catalytic exchange. From these model compounds the relative preparative applicability of the Wilzbach and catalytic techniques has been discussed.