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[摘要]:A novel and improved synthetic route includes four segment-couplings toward coelenterazine and its analogs as luminescent molecules. Regio- and chemo-selective cross coupling reactions using palladium catalysts with 5-iodo-3-bromo-2-aminopyrazine have enabled providing various aminopyrazine derivatives having different substituents. The improved synthesis of coelenterazine and its analogs employed advanced condensation with the aminopyrazines using various keto-acetal segments, which resulted in much higher yields to give the final imidazopyrazinone heterocycles than the previous method using keto-aldehydes. |
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