Studies on the synthesis of spiroheterocycles and their derivatives using dimedone as synthetic precursor

Abstract

Diarylidene ketones 1a–c, formed by the condensation of acetone with diverse appropriate aryl aldehydes undergo Micheal reaction with dimedone to afford the desired spiro compounds 2a–c. The spirodiarylidene derivatives 3a–l on cyclisation with hydrazine, phenyl hydrazine, hydroxyl amine, urea, thiourea and guanidine carbonate furnish the respective insitu oxidized pyrazole 4a–l, phenylpyrazole 5a–l, isoxazole 6a–l, pyrimidine 7a–l, aminopyrimidine 8a–l. The antibacterial activities of the synthesized compounds have been investigated against the gram negative Escherichia coli and gram positive bacteria Staphylococcus aureus.

Graphical Abstract

Diarylidene ketone undergo Micheal rection with dimedone to afford the spiro compounds followed by cyclisation with some bidentate ligands to furnish the respective insitu oxidized pyrazole, phenylpyrazole, isoxazole, pyrimidine, aminopyrimidine derivatives and the synthesized compounds were screened for their antibacterial activities.

Keywords:

• Antibacterial activities
• dimedone
• isooxazole
• pyrazole
• pyrimidine
• spiroheterocycles

Acknowledgments

The authors thank UGC (DRS-SAP), New Delhi for financial support, FIST-DST for providing infrastructural research facility and SAIF, IIT, Chennai for recording NMR and Mass spectra. The authors thank Prof. R.K. Behera for his valuable suggestions incorporated in this article. One of the authors S. Sahu is thankful to UGC for granting Teacher Fellowship for Ph.D. program.