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

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-carbon atom. 3H NMR analysis of tritiated isotopomers was used for the investigation of solid-state reactions. The HSCIE reaction proceeds selectively at 140oC and only part of the molecules is in the tritium spillover reaction zone. At 220oC HSCIE proceeds evenly along the whole mass to give uniformly labelled alanine. (author)