One-pot synthesis of highly functionalized pyrimido[1,2-b]indazoles via 6-endo-dig cyclization†
Abstract
An efficient synthesis of nitrogen ring junction pyrimido-indazoles has been developed. This is a metal catalyzed transformation that proceeds via A3 coupling reaction between 1H-indazol-3-amine, aromatic aldehydes and alkynes, which undergoes 6-endo-dig cyclization leading to the highly functionalized pyrimido[1,2-b]indazoles. Response surface methodology (RSM) was used to investigate the effect of catalyst (A1), reaction temperature (B1) and time (C1). The fluorescence quantum yields of the pyrimido[1,2-b]indazoles were calculated.