Regioselective synthesis of 5- and 6-methoxybenzimidazole-1,3,5-triazines as inhibitors of phosphoinositide 3-kinase

Michelle Susan Miller, Jo-Anne Pinson, Zhaohua Zheng, Ian Jennings, Philip Thompson

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13 Citations (Scopus)


Phosphoinositide 3-kinases (PI3K) hold significant therapeutic potential as novel targets for the treatment of cancer. ZSTK474 (4a) is a potent, pan-PI3K inhibitor currently under clinical evaluation for the treatment of cancer. Structural studies have shown that derivatisation at the 5- or 6-position of the benzimidazole ring may influence potency and isoform selectivity. However, synthesis of these derivatives by the traditional route results in a mixture of the two regioisomers. We have developed a straightforward regioselective synthesis that gave convenient access to 5- and 6-methoxysubstituted benzimidazole derivatives of ZSTK474. While 5-methoxy substitution abolished activity at all isoforms, the 6-methoxy substitution is consistently 10-fold more potent. This synthesis will allow convenient access to further 6-position derivatives, thus allowing the full scope of the structure-activity relationships of ZSTK474 to be probed.
Original languageEnglish
Pages (from-to)802 - 805
Number of pages4
JournalBioorganic and Medicinal Chemistry Letters
Issue number3
Publication statusPublished - 2013

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