Schiff bases compounds prepared from Phenyl hydrazine as a starting material were Synthesized, Characterized, and their Biological activity was Investigated


Nuha Salman Salih1, Widad Ibrahem Yahya2, Hutham Mahmood Yousif Al-Labban3,

Ahmed Abduljabbar Jaloob Aljanaby4*

1,2,3University of Kufa, Faculty of Science, Department of Chemistry, Iraq.

4University of Kufa, Faculty of Science, Department of Biology, Iraq.

*Corresponding Author E-mail:,,,



Preparation of Schiff bases compounds (A, B, and C) in absolute ethanol using concentrated phenyl hydrazine and various aromatic aldehydes such as (4-chlrobenzaldehyde aldehyde, 4-bromobenzaldehyde, N, N-dimethyl amino benzaldehyde). Melting point, FT, has been used to classify these compounds (A, B, and C). The reactions phases and series were studied using IR spectroscopy and thin layer chromatography (TLC) (ethyl acetate: toluene, 1:4). Three derivate compounds were used as antibacterial activity in this study. The results proved that all derivative compounds provided good inhibition zone against Staphylococcus aureus and pseudomonas aeruginosa especially in concentration 300mg/ml of derivative compound C with diameter inhibition zone 21.433±0.676 and 625.33±0.796 respectively.


KEYWORDS: Phenylhydrazine, Schiff bases, antibacterial activity, Staphylococcus aureus, pseudomonas aeruginosa, Iraq.




Hermann Emil Fischer reported the first hydrazine derivative in 1875, and it was phenylhydrazine1,2. He made it by utilizing sulfite salts to reduce a phenyl diazonium salt3,4. Fischer utilized phenylhydrazine to describe sugars by forming osazones from hydrazones formed by the sugar aldehyde. He also showed many of the essential characteristics of hydrazines in this initial publication5,6. The Fischer indole synthesis uses phenyl-hydrazine to make indoles, which are intermediates in the production of many colors and medicines7. Phenylhydrazine is used to create phenylhydrazones from natural combinations of simple sugars, allowing the sugars to be readily separated from one another8. The Azomethine group (-C=N-) is often referred to as a Schiff base because it is produced via the condensation of carbonyl compounds with a primary amine.9,10.


Because it is used in industrial applications and has excellent antibacterial action, the Azomethine group is an important chemical11,12



Procedure for Schiff base derivatives in general:

The phenylhydrazine molecule (0.01mole) was treated with a solution of different aromatic aldehydes (0.01mole) in 40ml 100% ethanol, and 3 drops of glacial acetic acid were added above the mixture13. For a period of (1-2) hours, reflexed the mixture14,15. Filtration, drying, and recrystallization of the precipitate from ethanol yielded compounds (A, B, and C), respectively, and TLC showed that the reaction was complete (ethyl acetate: toluene, 1:4). (A, B, and C) were the three compounds' names, respectively (Table 1 and Scheme 1).


Table 1: (A, B and C) Physical properties of Schiff base derivatives

Comp. No

Structural formula

Molecular formula













Decomposed at 180oC


















120 oC


















Decomposed at 150oC









Abbreviations: M. P=Melting point, Rf=Rate of flow


Scheme1: Synthesis steps of Schiff base compounds A, B and C.


Biological activity of three derivative compounds:

Three derivative compounds were tested for their ability to prevent the development of pathogenic bacteria has been obtained from patients with burn infection: Staphylococcus aureus (S. aureus) as a gram positive bacteria and pseudomonas aeruginosa (P. aeruginosa) as a gram negative bacteria. Pathogenic bacteria were kindly provided by the laboratory of microbiology at the University of Kufa Faculty of science. The well agar diffusion method was used to measure antibacterial activity as fallow: Two pathogenic bacteria were swabbed onto Muller-Hinton agar (Oxoid, UK) surface according to 0.5 McFarland turbidity16,17. Each derivative compound was made in three concentrations (100, 200, and 300mg/ml)18,19. Crock-poorer was used to make three wells in Muller-Hinton agar surface (Oxoid, UK) (Oxoid, UK)13,14. Every well received 50 l of each dilution, which was left at 20oC for two hours before being incubated at 37oC for 24 hours. Each examination was repeated three times. Every well's inhibition zone was calculated in millimeters20,21


Statistical analysis:

T-test comparisons between inhibition zone diameters is made using Graph-pad prism V.5 windows tools in statistical research. Meaning: If the p-value was smaller than 0.05, it was believed to be meaningful22,23



The reaction of phenyl hydrazine with various carbonyl derivatives to form Schiff bases compounds A, B, and C revealed an appearance band at (1510-1633) cm-1 of stretching vibration of the (C=N) imine groups (21) (Table 2) (Figure1-3).


Table 2: A, B, and C FT. IR data of Schiff base compounds.

Comp. No

Structural formula

υ (N-H)

υ (C-H)Str. Aromatic Aliphatic cm-1

υ (C=C)




υ (C=N) Str. Imine cm-1

δ(C-H) Bending cm-1












υ (C-Cl) Str.:











υ (C-Br) Str. :1066















Figure1:  Compound F.T.I.R. spectrum (A).


Figure2: Compound F.T.I.R. spectrum (B).


Figure3: Compound F.T.I.R. spectrum (C).


Effect of derivative compounds against pathogenic bacteria:

Table 3 shows the results of antibacterial activity of three derivative compounds against two pathogenic bacteria. The results proved that all derivative compounds provided good inhibition zone against S.aureus (Figure 4) and P. aeruginosa (Figure 5) especially in concentration 300 mg/ml of derivative compound C with diameter inhibition zone 21.433± 0.676 and 625.33±0.796 respectively, this inhibition action may be due to effect of compound N=C24.25,26,27.


Table3: Results of antibacterial activity of three derivative compounds against two pathogenic bacteria.

Derivative compound


P. aeruginosa

Con. (mg/ml)

M±SE mm(R=3)

Con. (mg/ml)

M±SE mm(R=3)




 8.1667 ± 0.440


12.833 ± 0.405


11.433 ± 0.902


16.167 ± 0.491


19.267 ± 0.674


18.23 ± 0.779




10.067 ± 0.520


17.53 ± 1.122


11.000 ± 0.577


19.13 ± 0.375


18.000 ± 0.577


24.17 ± 0.938




13.267 ± 0.560


19.80 ± 0.115


15.433 ± 0.317


22.63 ± 0.437


21.433 ± 0.676


25.33 ± 0.796

M±SE: Mean± Standard error, mm: Millimeter (diameters of inhibition zone), R: number of replicates


Figure4: Antibacterial activity of three derivatives compounds with concentration 300mg/ml against S.aureus onto Muller- Hinton agar at 37oC for 24H of incubation. 


Figure5: Antibacterial activity of three derivatives compounds with concentration 300mg/ml against P. aeruginosa onto Muller- Hinton agar at 37oC for 24H of incubation. 



The findings revealed that all derivative compounds at a concentration of 300 mg/ml showed excellent antibacterial activity against Staphylococcus aureus and pseudomonas aeruginosa isolated from burn patients.



In this project, there were no conflicts of interest.



There was no any fund in this study.



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Received on 22.06.2021           Modified on 13.08.2021

Accepted on 02.09.2021         © RJPT All right reserved

Research J. Pharm. and Tech. 2022; 15(8):3595-3598.

DOI: 10.52711/0974-360X.2022.00602