One Pot Synthesis of Novel Substituted 2',4'-Dihydrospiro[chroman-2,3'-pyrazol]-4- one Derivatives

Abstract

Aim and Objective: In the work, we have successfully presented a synthetic route for the synthesis of novel 2',4'-dihydrospiro[chroman-2,3'-pyrazol]-4-one derivatives via one pot multicomponent approach. Materials and Method: Substituted 2',4'-dihydrospiro[chroman-2,3'-pyrazol]-4-one were prepared through cascade three-component condensation of ortho-hydroxyacetophenone, β-ketoester, hydrazine in the presence of pyrrolidine as a catalyst under ethanol reflux conditions. Results: A series of novel 2',4'-dihydrospiro[chroman-2,3'-pyrazol]-4-one have been synthesized through a facile strategy. These structures of newly synthesized derivatives were determined by 1H, 13C NMR, HRMS and CHNS analysis. Conclusion: We have achieved the one-pot, three-component synthesis of highly substituted pyrazole spirochromanones in presence of pyrrolidine as a catalyst under ethanol reflux conditions. Using different types of aliphatic and aromatic β-ketoesters, o-hydroxyacetophenone derivatives and different kinds of hydrazine derivatives as building blocks, we could construct novel libraries of substituted pyrazole spirochromanones that make this method suitable for combinatorial and parallel synthesis in drug discovery.

Synthesis of Sulfonated Dihydrofuropyrazoles Derivatives as Antimicrobial Active Agents

“…In accordance with the increasing need to develop new and simple methods to prepare this biologically active sulfoxide bearing heterocyclic compounds [12][13][14][15][16][17]. Since few years onwards, our laboratory actively engaged with synthesis of different biologically active nitrogen and oxygen heterocyclic molecules by employing green chemical multicomponent approaches [18][19][20][21][22][23][24]. In the continuation of these efforts recently our group has developed novel methodology for synthesis of c]pyrazole-5-carboxylate (5a-q): Mixture of ethyl 3-oxo-5-(phenylthio)pentanoate (1) (385 mg, 0.153 mmol), hydrazine (2) (81 mg, 0.153), benzaldehyde (3a) (172 mg, 0.153 mmol), 1-(2-ethoxy-2-oxoethyl)pyridiniumylide (4) (272 mg, 0.153 mmol), 0.1 equivalents of trimethylamine (16 mg, 0.015 mmol) were refluxed in EtOH (5mL).…”