Synthesis, characterization and biological activity of Schiff bases based on chitosan and arylpyrazole moiety

*Reviewer Suggestions

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Page 2 of 31
Accepted Manuscript
[e-mail]
 
Department of chemistery, Bahra University, Waknaghat, India. 
(6)
Prof. Samira taha rabie 
[e-mail]
 
National Research Center, Dokki, Giza, Egypt. 

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Page 3 of 31
Accepted Manuscript
Abstract 
The Schiff bases of chitosan were synthesized by the reaction of chitosan with 3-(4-substituted-
phenyl)-1-phenyl-1H-pyrazole-4-carbaldehyde. The structure of the prepared chitosan 
derivatives was characterized by FTIR spectroscopy, elemental analysis, and X-ray diffraction 
studies and 
thermogravimetric 
analysis (TG). The
results show that the specific properties of 
Schiff bases of chitosan can be altered by modifying the molecular structures with proper 
substituent groups.TG results reveal that the thermal stability of the prepared chitosan Schiff 
bases was lower than chitosan. The activation energy of decomposition was calculated using 
Coats–Redfern model.
The antimicrobial activity of chitosan and Schiff bases of chitosan were 
investigated against Streptococcus pneumonia, Bacillis subtilis, Escherichia coli (as examples of 
bacteria) and Aspergillus fumigatus, Geotricum candidum and Syncephalastrum recemosum (as 
examples of fungi). The results indicated that the antimicrobial activity of the Schiff bases was 
stronger than that of chitosan and was dependent on the substituent group. The activity of un-
substituted arylpyrazole chitosan derivative toward the investigated bacteria and fungi species 
was better than the other derivatives. 
Key words 
Chitosan Schiff bases; Thermal properties; Antimicrobial activity 
Corresponding author: Magdy W. Sabaa ([e-mail]) 
Abstract

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Page 4 of 31
Accepted Manuscript
Dear Editor 
I would like first to thank the Referees for their valuable comments that helped us to revise the 
manuscript more thoroughly. All their suggestions have been considered in the revised 
manuscript. I hope that you will find the manuscript in its revised form adequate for publication 
in Internal Journal of Biological Macromolecules. 
Thanking you in anticipation for your cooperation, I remain
Sincerely yours 
Prof. Magdy W. Sabaa 
Emeritus Prof. of Polymer Chemistry, 
Faculty of Science, Cairo University 
Response to Reviewer’s comments: 
- The introduction was modified to become more specified to the used derivatives of chitosan. 
- The stretching vibration of NO
2
,Cl, Ph-ring, CN and C-C of Chitosan Schiff Bases (ChBs) 
was added in the revised manuscript.
- The spectroscopic characterization data (FT-IR and 
1
H NMR) of the synthesized 3-(4-
substituted-phenyl)-1-phenyl-1H-pyrazole-4-carbaldehyde compounds was supplied as 
supplementary information. 
- The explanation of TG-DTG and DTA data of the prepared chitosan Schiff bases was clarified. 
- Several modern references was added in the revised manuscript. 
- Editing for the manuscript English and the typomistakes and grammatical errors were 
corrected. 
- The units are adjusted to match the style of the Journal. 
- The molecular weight of chitosan is added in the experimental part.