A novel synthesis of tetra and pentacyclic quinolinopyran tethered pyrazole/coumarin scaffolds via a solid state melt reaction

Progress in the Chemistry of Tetrahydroquinolines

“…This diastereoand regioselective domino process takes place via an initial Knoevenagel condensation to give intermediate A followed by an intramolecular hetero Diels−Alder reaction (Scheme 40). 139 Almost simultaneously, Pandit and Lee described a closely related transformation. 140 In a related work, starting from aldehydes 211 and leading to the same framework 214, the pyrazolone derivative was generated in situ from a β-ketoester 212 and phenylhydrazine 213, as shown in Scheme 41.…”

Coumarin heterocyclic derivatives: chemical synthesis and biological activity

“…211 Thus, mixtures of Baylis-Hillman derivatives 291 and 4-hydroxycoumarin 26 were melted at 180 C for 1 h to yield pure products in high yields and cis geometry, without catalyst or solvent (Scheme 92).…”

“…207 When the 2- Recently, Bakthadoss and coworkers developed a protocol for the efficient synthesis of structurally diverse tetra-and pentacyclic quinolinopyran-tethered coumarin architectures 293 via a domino Knoevenagel intramolecular hetero-Diels-Alder strategy under solvent-free conditions. 211 Thus, mixtures of Baylis-Hillman derivatives 291 and 4-hydroxycoumarin 26 were melted at 180 C for 1 h to yield pure products in high yields and cis geometry, without catalyst or solvent (Scheme 92).…”

A distal vinyl shift (DVS) through quadruple domino reaction: synthesis of N-vinyl benzoheterocyclic scaffolds

“…Heterocyclic compounds bearing nitrogen and oxygen atoms are extremely abundant in nature and display a wide array of bioactivities which make them highly useful in the field of pharmaceuticals and agrochemicals owing to a large number of applications. Therefore, synthesis of highly functionalized nitrogen and oxygen containing heterocyclic 1 compounds possessing interesting medicinal applications is a challenging area in organic synthesis. The synthesis of a complex heterocyclic scaffold utilizes many steps which can be drastically reduced when reactions are carried out in a domino fashion.…”