Tritium-labeled compounds IX. Determination of isotope effects in reactions yielding water-t from nonvolatile reactants. Oxidation of aldoses-1-t with iodine

A convenient m ethod is presented for estimating isotope effects in reactions wh ich yield water-to The water-t is separated by freez e-!=h~yjng, and k* /k is calculated froJ?.t!J.e extent of the reaction and the ratio of the radioactIvIty of t he water-t to that of the lnItlal reactant.Application of the m ethod to the oxidation of aJdoses-1-t at 25°C with iodine in a lkaline solution gives values fo r k*/ k ranging from 0.12 to 0.~7 , with an averag:e of.0 .1~.There are no significant d ifferences in the values of k* /k .0btaIned for aldoses dl~e nng 1Il configuration, or for pentoses and hexoses.Th e isotope effect corresponds to a ratlO of one to seven for the respective rates of reaction of the labeled and un labeled m.olccules.