Synthesis of [11C] coenzyme Q-related compounds for in vivo estimation of mitochondrial electron transduction and redox state in brain

We have studied the synthesis of [11C]2,3-dimethoxy-5-methyl-6-(10-hydroxy)-decyl-1,4-benzoquinone (idebenone) and [11C]2,3-dimethoxy-5-methyl-1,4-benzoquinone (CoQ0) by methylation of their respective desmethyl precursors using [11C]CH3I for in vivo measurement of mitochondrial electron transfer and redox state. The [11C]idebenone was more lipophilic than [11C]CoQ0; the latter became hydrophilic by reduction. Clearance of [11C]idebenone from mouse brain was more rapid than that of [11C]CoQ0. The results indicated that modification of the isoprenoid side chain in [11C]CoQ is necessary to develop more suitable radiopharmaceuticals