Deuteration of benzen derivatives and condensed aromatics

A process for the deuteration of aromatic compounds (benzene derivatives having one or more cyano, halogeno, nitro or other electron attractive groups, and condensed ring aromatics) is provided. The process comprises reducing said aromatic compound with an alkali metal (preferably K, Rb or Cs) in a solvent (dimethoxyethane, tetrahydrofuran, etc.) to provide an electron-acceptor-donor complex, which is followed by introducing gaseous deuterium into the solution. The deuteration takes place selectively at the position of highest electron density in accordance with nature of the substituent, regardless of steric hindrance. The process is applicable to a wide variety of aromatics to give deuterated compounds in high yields. In one example, 5x10-3 mole of anthracene (An) was reacted with 2g of metallic potassium in 80cc of dimethoxyethane in a N2 atmosphere. Into the resulting solution of An=2K+ was introduced D2 gas (30 cmHg) at 250C. After decomposition with air and washing with alcohol, the precipitate was recrystallized from benzene. Yield of recovered AN: more than 90%. Yield of deuteration: 100%. Position of deuteration: 9 and 10 (revealed by NMR and mass spectroscopy). (Kaichi, S.)