Title:One-Step, Low-Cost, Operator-Friendly, and Scalable Procedure to Synthetize Novel
Tetrazolopyrimidinylbenzopyran-2-ones by Benign Protocol
Volume: 26
Issue: 24
Author(s): Eman A. Ahmed, Ahmed Khodairy, Mahmoud Abd El Aleem Ali Ali El-Remaily*Abdelraheem M. Ahmed
Affiliation:
- Department of Chemistry, Faculty of Science, Sohag University, Sohag, 82524, Egypt
Keywords:
5-Aminotetrazole, 3-acetyl coumarin, chalcones, pyrimidines, benign protocol, three-component reaction, condensation.
Abstract: New coumarin chalcones 3j-p were conveniently obtained in high yields via
Claisen-Schmidt condensation reaction, when acetyl coumarin 1 reacted with 3-aryl-1-phenyl
pyrazole-4-carbaldehydes 2j-p in boiling ethanol in the presence of triethyl amine as a catalyst.
Also, two synthetic pathways were afforded for the synthesis of novel tetrazolo[1,5-
a]pyrimidinyl-2H-chromen-2-ones 5a-p. The first pathway is a multistep process including
formation and separation of chalcones, which then were allowed to react with 5-aminotetrazole
4. While, the second pathway is a highly efficient one-pot three-component condensation reaction
of 3-acetyl coumarin 1, aromatic aldehydes 2a-p and 5-aminotetrazole 4 under green and
mild reaction conditions by using acetic acid (AcOH) as a catalyst and solvent. The molecular
structure of products was established on the basis of their NMRs, IR and elemental analysis
data. Solvent optimization was carried out in the reaction producing 3-(5-Phenyl-4,5-dihydrotetrazolo[1,5-
a]pyrimidin-7-yl)-2H-chromen-2-one (5a). The advantages to using environmental-friendly acetic acid are simple
operation, short reaction time, high efficient (97%), operationally facile and wide tolerance of starting materials.