The synthesis of tritium-labelled alanine by solid-state catalytic reactions

Abstract

The solid-state catalytic hydrogenation (SCH) of unsaturated precursor compound and the high-temperature solid-state catalytic isotope exchange (HSCIE) showed that the total incorporation of isotope and its distribution between the α-and β-positions of the alanine molecule can be modified by changing the temperature of solid state reactions. Tritium incorporation at high-temperatures proceeds in a manner which retains the configuration of the asymmetric α-carbone atom. 3H NMR analysis of tritiated isotopomers was used for the investigation of solid-state reactions. The HSCIE reaction proceeds selectively at 140 °C and only part of the molecules is in the the tritium spillover reaction zone. At 220°C HSCIE proceeds evenly along the whole mass to give uniformly labelled alanine.