The College of Pharmacy discussed the PhD dissertation entitled “Synthesis, Docking studies & Cytotoxic Evaluation of New 4-Amino-3-Chloro Benzoic Acid Derivatives”, by the student Nedaa Abd Al hameed and her supervisor, Professor Dr. Ammar A. Razzak Mahmood, at the pharmaceutical chemistry Department.
The study aimed to synthesize new pharmaceutical derivatives from the starting material 4-amino-3-chlorobenzoic acid and to characterize those compounds using spectroscopic techniques (Infrared spectroscopy, proton and carbon nuclear magnetic resonance, and mass spectrometry). The study also evaluated the preliminary toxicity against three types of cancer cells as well as the use of a non-cancerous (normal) cell. Moreover, the toxicity of the derived compounds was tested, and IC50 values were extracted. The ability of the compounds to inhibit EGFR enzymes and histone deacetylase (HDAC) was also tested, yielding EC50 values. Additionally, a computer study (molecular docking) was conducted for the synthesized compounds.
The study included the synthesis of a derivative of the compound N1 using ethanol with thionyl chloride, while 4-amino-3-chlorobenzoic acid reacted with ethyl bromoacetate in the presence of anhydrous potassium carbonate as a catalyst, resulting in the compound A1. The compounds A1 and N1 were reflexed with hydrazine hydrate to produce the compounds A2 and N2, respectively. The oxadiazole 2-thion derivatives of the compounds N3 and A4 were prepared by treating the compounds A2 and N2 with CS2 (carbon disulfide) and alcoholic potassium hydroxide. Meanwhile, the compounds N3 and A4 were treated by reacting with different substituted phenyl bromide derivatives to produce the desired compounds: N3a-d and A4an-dn, which contain a 1,3,4-oxadiazole group. The compounds A2 and N2 reacted with substituted aromatic aldehydes in the presence of a small amount of glacial acetic acid (catalyst) to produce the compounds N4a-c and (A3an – A3bn). Finally, the compounds A2 and N2 reacted with different substituted phenyl isothiocyanate derivatives at temperatures ranging from 40 to 50 degrees Celsius with continuous stirring to produce the compounds N5a–d and A5an-cn.
The study showed that the compounds N5a and A3bn have a lower IC50 value compared to erlotinib and SAHA. The ability of the compounds from the first group to inhibit the EGFR enzyme was tested by extracting EC50 values compared to erlotinib, while the ability of the compounds from the second group to inhibit the histone deacetylase (HDAC) enzyme was also evaluated. It was found that the compound N4b is the best compound in the first group compared to erlotinib, and that the compound A3bn is the best compound in the second group compared to SAHA and trichostatin. Additionally, a computer study (molecular docking of binding) for those manufactured compounds with EGFR for the first group and HDAC 2, 6, 8 for the second group showed that the compound N5a provided the best binding result compared to erlotinib, while the compound A3bn from the second group showed the highest binding value with the HDAC 2 enzyme. The study indicated that the compound N5a from the first group is promising for killing cancer cells, and immunoblot analysis showed that it increases the activity of caspase 3 and 8, whereas the compound A3bn from the second group was found to increase caspase 8.
The study recommended taking into account compound N5a from the first group and compound A3bn from the second group, and conducting additional laboratory analyses to confirm the drug’s kinetics and compare it with the results obtained through molecular docking.
