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.
Synthetic fermentation of β-peptide macrocycles by thiadiazole-forming ring-closing reactions
