摘要：

New shelf-stable pyridylboronic acids have been synthesized: bromine-lithium exchange followed by reaction with triisopropylborate (TIPB) yielded 2-fluoro-5-pyridylboronic acid (4), 3-bromo-5-pyridylboronic acid ( 5) and 2-ethoxy-5-pyridylboronic acid ( 6); directed lithiation followed by reaction with trimethylborate (TMB) or TIPB afforded 2-methoxy-3-pyridylboronic acid (8), 3-bromo-6-methoxy-4-pyridylboronic acid ( 11) and 3-bromo-6-ethoxy-4-pyridylboronic acid ( 12). Cross-coupling of pyridylboronic acids 4, 6, 8, and 11 with 3-bromoquinoline [Cs 2CO 3, Pd(PPh 3) 2Cl 2, 1,4-dioxane, 95 °C] gave pyridinylquinoline derivatives 13, 15- 17 in 50-77% yields: the analogous reaction of 5 was low yielding due to further in situ reactions of the product 14. Cross-coupling of 12 with 2-bromo-5-nitrothiophene gave 3-bromo-4-(5-nitro-2-thienyl)-6-ethoxypyridine ( 18).

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