A new application of two Negishi-type coupling reactions for the synthesis of coelenterazine is reported. The synthesis of coelenterazine in high purity on a gram scale will enable numerous approaches to bioluminescence imaging and possibly photodynamic therapy of deep-seated tumors. Coelenterazine is the substrate for several luciferases, among them Gaussia luciferase (gLuc). This synthesis starts with pyrazin-2-amine and uses inexpensive starting materials and catalysts.
Key words
palladium - zinc - organometallic reagents - Grignard reaction - regioselectivity - Negishi coupling