Selectivity of amidrazones towards activated nitriles – synthesis of new pyrazoles and NMR investigation

Ashraf A Aly,Alan B Brown,Mohamad Ramadan,Stefan Bräsee,Mohamed Abd El-Aziz,Hazem M Fathy

doi:10.24820/ark.5550190.p009.877

Abstract

Selectivity of amidrazones towards activated nitriles – synthesis of new pyrazoles and NMR investigation

Highlights

Amidrazones are convenient building blocks for various heterocycles.[1,2,3,4,5] Recently, we have reported that amidrazones reacted with 2,3-diphenylcyclopropenone via extrusion of ammonia to give 3-(aryl)-2,5,6-triphenylpyrimidin-4(3H)-ones.[6]For a very long time, the usefulness and great therapeutic value of the pyrazole nucleus have been recognized and the activities of this nucleus have been evaluated.[7]
Many modifications of the pyrazole nucleus were attempted and several compounds have been synthesized for the treatment of different conditions like inflammation, pain, cancer, tuberculosis, and diseases caused by bacteria
Molecular modeling studies showed that pyrazole analogs interact with the cyclooxygenase-2 (COX-2) active site by classical hydrogen bonding, π-π interaction, and cation–π interaction which increases the residence of the ligand in the active site, augmenting the anti-inflammatory activity of the compounds.[11]

Summary

Introduction

Amidrazones are convenient building blocks for various heterocycles.[1,2,3,4,5] Recently, we have reported that amidrazones reacted with 2,3-diphenylcyclopropenone via extrusion of ammonia to give 3-(aryl)-2,5,6-triphenylpyrimidin-4(3H)-ones.[6]For a very long time, the usefulness and great therapeutic value of the pyrazole nucleus have been recognized and the activities of this nucleus have been evaluated.[7]. Elemental analyses and IR, NMR, and mass spectra were in good agreement with the assigned product structures. The methyl carbon gives HMBC correlation with a 2H doublet at H = 6.92, assigned as H-m’; the attached carbons appear at C = 127.7.

Results

Conclusion