Synthesis of ximelagatran, melagatran, hydroxymelagatran, and ethylmelagatran in H-3 labeled form

In support of a study designed to better understand the liver toxicity of ximelagatran, ximelagatran, and melagatran, hydroxymelagatran and ethylmelagatran were prepared in tritium labeled form. Incorporation of tritium was achieved by hydrogen isotope exchange using Crabtree's catalyst and later with N-heterocyclic containing Ir catalyst. The tritiated product was then converted into the four target compounds to afford them in high purity and specific activity.