Synthesis of N-pyridyl azoles using a deprotometalation-iodolysis-N-arylation sequence and evaluation of their antiproliferative activity in melanoma cells

N-Arylation of pyrrole with 3-iodo-4-methoxypyridine was investigated by copper catalysis under different conditions. The best conditions, that proved to be protocol A (CuI, DMEDA or TMEDA, K3PO4, DMF at 110 °C) and above all protocol B (Cu2O, Cs2CO3, DMSO at 110 °C), were applied to the synthesis of various N-(methoxypyridyl) pyrroles, indoles and benzimidazoles. The behavior of the different iodinated methoxypyridines was rationalized by evaluating the partial positive charge on the carbon bearing iodine from the 1H NMR chemical shift of the corresponding deiodinated substrates. The reaction was next connected with the deprotometalation-iodolysis step generating iodinated methoxypyridines: straight involvement of the crude iodo intermediates in pyrrole N-arylation afforded the expected N-(methoxypyridyl) pyrroles in good yields. Several synthesized N-(methoxypyridyl) azoles exerted low to moderate antiproliferative activity in A2058 melanoma cells. [Display omitted]