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Synthesis and antimicrobial activity of some novel cross-linked chitosan hydrogels.

Mohamed NA, Fahmy MM - Int J Mol Sci (2012)

Bottom Line: Their structures were confirmed by fourier transform infrared X-ray (FTIR), scanning electron microscopy (SEM) and X-ray diffraction.The prepared hydrogels showed much higher antimicrobial activities than that of the parent chitosan.Increasing the degree of cross-linking in the hydrogels resulted in a weaker antimicrobial activity.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Faculty of Science, Cairo University, Giza 12613, Egypt; E-Mail: m.fahmy17@yahoo.com.

ABSTRACT
Four novel hydrogels based on chitosan were synthesized via a cross-linking reaction of chitosan with different concentrations of oxalyl bis 4-(2,5-dioxo-2H-pyrrol- 1(5H)-yl)benzamide. Their structures were confirmed by fourier transform infrared X-ray (FTIR), scanning electron microscopy (SEM) and X-ray diffraction. The antimicrobial activities of the hydrogels against two crop-threatening pathogenic fungi namely: Aspergillus fumigatus (A. fumigatus, RCMBA 06002), and Aspergillus niger (A. niger, RCMBA 06106), and five bacterial species namely: Bacillis subtilis (B. subtilis, RCMBA 6005), Staphylococcus aureus (S. aureus, RCMBA 2004), Streptococcus pneumoniae (S. pneumonia, RCMB 000101) as Gram positive bacteria, and Salmonella typhimurium (S. typhimurium, RCMB 000104), and Escherichia coli (E. coli, RCMBA 5003) as Gram negative bacteria have been investigated. The prepared hydrogels showed much higher antimicrobial activities than that of the parent chitosan. The hydrogels were more potent in case of Gram-positive bacteria than Gram-negative bacteria. Increasing the degree of cross-linking in the hydrogels resulted in a weaker antimicrobial activity.

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Synthesis of oxalyl bis 4-(2,5-dioxo-2H-pyrrol-1(5H)-yl)benzamide.
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f5-ijms-13-11194: Synthesis of oxalyl bis 4-(2,5-dioxo-2H-pyrrol-1(5H)-yl)benzamide.

Mentions: Oxalyl bis 4-(2,5-dioxo-2H-pyrrol-1(5H)-yl)benzamide was synthesized from maleic anhydride, p-amino-benzoic acid and oxamide, as shown in Scheme 2. Maleic anhydride (1 mol) and p-aminobenzoic acid (1 mol) were dissolved in DMF (320 mL), then the mixture was stirred at room temperature for 5 h under nitrogen atmosphere. The resulting solution was then poured into a large amount of water to precipitate crude N-(4-carboxyphenyl) maleamic acid, which was filtered, dried and recrystallized from water (yield = 97%; mp 223–225 °C) (Literature [32] mp 225–226 °C). Then, a mixture of N-(4-carboxyphenyl) maleamic acid (0.2 mol), acetic anhydride (100 mL) and anhydrous sodium acetate (2.5 g) was stirred at 55–60 °C for 2 h. The reaction mixture was poured onto a large amount of water to give crude N-(4-carboxyphenyl) maleimide, which was filtered and washed with water, dried and recrystallized from methanol:water (6:1) mixture (yield = 85%; mp 211–212 °C) (Literature [33] mp 208–210 °C). Then, a mixture of N-(4-carboxyphenyl)maleimide (0.16 mol), thionyl chloride (4.02 mol) and tert-butylcatechol (0.01 g) was refluxed for 2 h. Unreacted thionyl chloride was evaporated out, and then the residual product was recrystallized from benzene to obtain pure N-[4-(chlorocarbonyl)phenyl]maleimide, (yield = 73.3%; mp 166–167 °C) (Literature [32] mp 168–169 °C). Finally, a solution of 3.52 g (0.04 mol) oxamide dissolved in 100 mL DMF was stirred well, and allowed to cool at −10 °C using an ice-salt bath for 15 min. Then 18.84 g (0.08 mol) solid N-(4-chloro-carbonylphenyl) maleimide was added slowly with constant stirring for 1 h. The ice-salt bath was removed to let the temperature of the condensation reaction rise gradually to room temperature, and it was maintained for an additional 2 h with stirring. The reaction mixture was slowly poured onto methanol-water mixture (1:2), upon which a white precipitate of oxalyl bis 4-(2,5-dioxo- 2H-pyrrol-1(5H)-yl)benzamide was immediately formed. The product was filtered, dried and recrystallized from a methanol:water (1:1) mixture, (yield 75.8%; mp 233–235 °C). Elemental analyses: Calcd: 59.26% C; 2.88% H; 11.52% N; Found: 58.91% C; 2.96% H; 11.35% N. MS m/z: 486 (M+). FTIR spectrum (Figure 1b) showed a specific band for a maleimide moiety at 821 cm−1, while two strong bands appeared at 1511 and 1598 cm−1 corresponding to the stretching vibration for aromatic rings. A specific very strong band appeared at 1711 cm−1 for the C=O of the imide linkages of the maleimide moiety. Also the –NH– stretching band appeared at 3164 cm−1.


Synthesis and antimicrobial activity of some novel cross-linked chitosan hydrogels.

Mohamed NA, Fahmy MM - Int J Mol Sci (2012)

Synthesis of oxalyl bis 4-(2,5-dioxo-2H-pyrrol-1(5H)-yl)benzamide.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3472739&req=5

f5-ijms-13-11194: Synthesis of oxalyl bis 4-(2,5-dioxo-2H-pyrrol-1(5H)-yl)benzamide.
Mentions: Oxalyl bis 4-(2,5-dioxo-2H-pyrrol-1(5H)-yl)benzamide was synthesized from maleic anhydride, p-amino-benzoic acid and oxamide, as shown in Scheme 2. Maleic anhydride (1 mol) and p-aminobenzoic acid (1 mol) were dissolved in DMF (320 mL), then the mixture was stirred at room temperature for 5 h under nitrogen atmosphere. The resulting solution was then poured into a large amount of water to precipitate crude N-(4-carboxyphenyl) maleamic acid, which was filtered, dried and recrystallized from water (yield = 97%; mp 223–225 °C) (Literature [32] mp 225–226 °C). Then, a mixture of N-(4-carboxyphenyl) maleamic acid (0.2 mol), acetic anhydride (100 mL) and anhydrous sodium acetate (2.5 g) was stirred at 55–60 °C for 2 h. The reaction mixture was poured onto a large amount of water to give crude N-(4-carboxyphenyl) maleimide, which was filtered and washed with water, dried and recrystallized from methanol:water (6:1) mixture (yield = 85%; mp 211–212 °C) (Literature [33] mp 208–210 °C). Then, a mixture of N-(4-carboxyphenyl)maleimide (0.16 mol), thionyl chloride (4.02 mol) and tert-butylcatechol (0.01 g) was refluxed for 2 h. Unreacted thionyl chloride was evaporated out, and then the residual product was recrystallized from benzene to obtain pure N-[4-(chlorocarbonyl)phenyl]maleimide, (yield = 73.3%; mp 166–167 °C) (Literature [32] mp 168–169 °C). Finally, a solution of 3.52 g (0.04 mol) oxamide dissolved in 100 mL DMF was stirred well, and allowed to cool at −10 °C using an ice-salt bath for 15 min. Then 18.84 g (0.08 mol) solid N-(4-chloro-carbonylphenyl) maleimide was added slowly with constant stirring for 1 h. The ice-salt bath was removed to let the temperature of the condensation reaction rise gradually to room temperature, and it was maintained for an additional 2 h with stirring. The reaction mixture was slowly poured onto methanol-water mixture (1:2), upon which a white precipitate of oxalyl bis 4-(2,5-dioxo- 2H-pyrrol-1(5H)-yl)benzamide was immediately formed. The product was filtered, dried and recrystallized from a methanol:water (1:1) mixture, (yield 75.8%; mp 233–235 °C). Elemental analyses: Calcd: 59.26% C; 2.88% H; 11.52% N; Found: 58.91% C; 2.96% H; 11.35% N. MS m/z: 486 (M+). FTIR spectrum (Figure 1b) showed a specific band for a maleimide moiety at 821 cm−1, while two strong bands appeared at 1511 and 1598 cm−1 corresponding to the stretching vibration for aromatic rings. A specific very strong band appeared at 1711 cm−1 for the C=O of the imide linkages of the maleimide moiety. Also the –NH– stretching band appeared at 3164 cm−1.

Bottom Line: Their structures were confirmed by fourier transform infrared X-ray (FTIR), scanning electron microscopy (SEM) and X-ray diffraction.The prepared hydrogels showed much higher antimicrobial activities than that of the parent chitosan.Increasing the degree of cross-linking in the hydrogels resulted in a weaker antimicrobial activity.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Faculty of Science, Cairo University, Giza 12613, Egypt; E-Mail: m.fahmy17@yahoo.com.

ABSTRACT
Four novel hydrogels based on chitosan were synthesized via a cross-linking reaction of chitosan with different concentrations of oxalyl bis 4-(2,5-dioxo-2H-pyrrol- 1(5H)-yl)benzamide. Their structures were confirmed by fourier transform infrared X-ray (FTIR), scanning electron microscopy (SEM) and X-ray diffraction. The antimicrobial activities of the hydrogels against two crop-threatening pathogenic fungi namely: Aspergillus fumigatus (A. fumigatus, RCMBA 06002), and Aspergillus niger (A. niger, RCMBA 06106), and five bacterial species namely: Bacillis subtilis (B. subtilis, RCMBA 6005), Staphylococcus aureus (S. aureus, RCMBA 2004), Streptococcus pneumoniae (S. pneumonia, RCMB 000101) as Gram positive bacteria, and Salmonella typhimurium (S. typhimurium, RCMB 000104), and Escherichia coli (E. coli, RCMBA 5003) as Gram negative bacteria have been investigated. The prepared hydrogels showed much higher antimicrobial activities than that of the parent chitosan. The hydrogels were more potent in case of Gram-positive bacteria than Gram-negative bacteria. Increasing the degree of cross-linking in the hydrogels resulted in a weaker antimicrobial activity.

Show MeSH
Related in: MedlinePlus