PROCESS FOR PREPARATION OF 2-(6-NITROPYRIDIN-3-YL)-9H-DIPYRIDO[2,3-B;3',4'-D]PYRROLE

A process for preparing the compound of formula Icomprising:a) coupling a compound of formula 2wherein a leaving group O-SO2-R is selected from the triflate group, the tosylate group, the mesylate group, the besylate group, the nosylate group or the brosylate group,with a suitable boronic acid, a trifluoroborate or a boronic acid esterunder argon condition and in the presence of a catalyst and a base in a suitable solvent and then isolating the product as an acid addition saltto afford the compound of formula Iaandb) converting the acid addition salt of formula Iawherein the acid HX comprises suitable organic or inorganic acids into the compound of formula Iby treatment with at least a stoichiometric equivalent of a suitable base.