Benzofuro[3,2-b]pyridines as mixed and selective ETB endothelin receptor antagonists

Achievement of regioselectivity in transition metal-catalyzed direct C–H (hetero)arylation reactions of heteroarenes with one heteroatom through the use of removable protecting/blocking substituents or traceless directing groups

“…Again in 2015, Min Wang, Lei Wang and coworkers developed a novel, efficient and regioselective synthesis of benzofuro [2,3-b]pyridine N-oxides 244 involving the Pd-catalyzed oxidative cyclization of 3-aryloxypyridine-1-oxides 243. 147 Compounds 243 were in turn synthesized according to the literature 148 Compounds 244 are known to include non-selective endothelin ET A /ET B as well as selective ET B receptor anatagonists, 150 inhibitors of topoisomerase II, 151 and derivatives that inhibit the tumor growth and metastasis. 152 Remarkably, 3-(2-chlorophenoxy)pyridine-pyridine-1oxide and 3-(4-chloro-3-methylphenoxy)-1-oxide underwent C-H/C-H cyclization reaction rather than C-H/C-Cl coupling reaction providing compounds 244w and 244x (Figure 18) in 54 and 49% yield, respectively.…”

Facile Synthesis of Novel Functionalized Pyridine Annulated Oxirane Methyl Coumarins

“…The other promising properties of this scaffold, like DNA adduct formation and energy transfer in photophysical pathway , make them promising molecular building blocks for further activity explorations. The benzofurano[3,2‐ b ]pyridines and tetrahydropyridines were reported as potential anti‐allergic agents and endothelin receptor antagonists and antidepressants (Fig. ).…”

An Efficient Synthesis of Chromeno[4,3-d]isoxazolo[5,4-b]pyridin-6-one Derivatives

“…Many important compounds containing coumarin and pyridine skeleton (Fig. ) have been reported as potential anti‐allergic agents and endothelin receptor antagonists . The tetrahydropyridines have been identified as potential anti‐depressants .…”