Synthesis and Crystallographic Characterisation of Pyridyl- and Indoleninyl-Substituted Pyrimido[1,2-b]Indazoles

Pyridyl- and indoleninyl-substituted pyrimido[1,2-b]indazole were synthesised in good to high yields from the condensation reaction of 1,3-dialdehydes with 3-aminoindazoles. The structural features compounds determined by NMR (1H, 13C 19F), FT-IR HR-MS. spectroscopic assignments confirmed X-ray crystallography for two derivatives, i.e., 9-Bromo-3-(pyridin-4-yl)pyrimido[1,2-b]indazole (1b) 10-Methoxy-3-(pyridin-4-yl)pyrimido[1,2-b]indazole (1c), which further provides support significant delocalisation π-electron density over entire fused ring system. molecular packing was assessed conventional methods together Hirshfeld surface analyses. In 1b, pyrimidyl-N–H···N(pyrimidyl), π(pyrazolyl)···π(pyrimidyl) Br···N interactions within a two-dimensional array. 1c, pyrimidyl-C–H···N(pyrazolyl) pyridyl-C–H···O(methoxy) feature three-dimensional architecture.