Bicyclic 6-6 Systems with One Bridgehead (Ring Junction) Nitrogen Atom: One Extra Heteroatom 1:0

Regio- and Diastereoselective Synthesis of Dihydropyridopyrimidines via Cascade Reactions of 2-Aminopyridines with Morita–Baylis–Hillman Bromides of Nitroalkenes

“…Numerous small bioactive molecules have evolved from the pyrido­[1,2- a ]­pyrimidine skeleton which now emerged as a privileged scaffold in medicinal chemistry . Various pyrido­[1,2- a ]­pyrimidines employed in human therapy include neuroleptic risperidone, tranquilizer pirenperone, antiallergic ramastine, antidepressant lusaperidone, and non-narcotic analgesic rimazolium (Figure ).…”

Tf2O-Mediated Cyclization of α-Acyl-β-(2-aminopyridinyl)acrylamides: Access to N-Substituted 4H-Pyrido[1,2-a]pyrimidin-4-imines

“…Over the past decades, pyrido­[1,2- a ]­pyrimidines and their derivatives have emerged as one of the most important N-fused bicyclic heterocycles because of their presence in numerous natural products and synthetic molecules along with a broad range of bioactivities , and their diverse applications in pharmaceuticals, agrochemicals, and advanced functional materials. , In this family, pyrido­[1,2- a ]­pyrimidin-4-ones have been demonstrated to possess antiatherosclerotic, antipyretic, antipsychotic, antiallergic, antidepressant, analgestic, and analgesic properties, , and some are now in clinical use . Their pharmacological importance has directed considerable research activity toward the development of efficient synthetic approaches for such kind of heterocycles and expanded their scope in the field of medicinal chemistry …”