Description:Background of the invention:
In human society, after cardiovascular disease cancer is the second largest deadliest disease and around 9 million people die every year which will rise up to 13.1 million by 2030 (Eur. J. Med. Chem. 2020, 203, 112506; Eur. J. Med. Chem. 2019, 163, 136-147; Eur. J. Med. Chem. 2019, 183, 111691). Nowadays, Chemotherapy and FDA approved anti-cancer agents are the main tool for cancer treatment (Eur. J. Med. Chem. 2019, 183, 111691). However, anti-cancer agents are not target specific and highly toxic, which have adverse effects during cancer treatment whereas in chemotherapy, drug resistance is a major problem (Trends. Cancer. 2019, 5, 170-182). Hence, there is an urgent need to synthesize and develop new anti-cancer agents with low toxicity and great potency. Nowadays, around 60% of available drugs in the market contain one or more heterocyclic moiety. Heterocyclic nucleus improves pharmacokinetics properties such as bioavailability and oral absorption as well as improves solubility and salt formation tendency of the molecule (Eur. J. Med. Chem. 2020, 187, 111909). In heterocyclic chemistry, 2-aminothiazole scaffold has gained significant attention in drug discovery research and medicinal chemistry. It consists of one amino group and one thiazole nucleus (Eur. J. Med. Chem. 2016, 109, 89-98). Amino group can be linked to different active groups through different reactions. New biologically potent molecules were synthesized by substitution at different positions (Arch. Pharm. 1983, 316(11), 941-951). Antifungal drug, Abafungin, contains thiazole ring which is used to treat both growing and resting phase of fungi and currently being used for treatment of dermatomycoses (Eur. J. Med. Chem. 2019, 181, 111587). Furthermore, amino group linked to 2,4-dimethoxyphenyl group enhances the anti-proliferative activity by targeting microtubule system in a dose dependent manner as well as in G2/M phase, in time- and concentration- dependent manner, it arrests SGC-7901cells (PLoS. One. 2017, 12(3), e0174006). Moreover, 2-aminothiazole scaffold is the essential anti-cancer agent which targets epidermal growth factor (EGFR) kinase, tubulin protein, BRAF kinase, sphingosine kinase (SphK) (Eur. J. Med. Chem. 2021, 210, 112953). Considering the above mentioned facts, it is always beneficial to design, synthesize and develop new compounds that have anticancer potential. Therefore, 2-(Bromosubstituted arylamino)-4-arylthiazoles were considered as anticancer agents and accordingly some new 2-amino-4-arylthiazole derivatives synthesized to investigate their anticancer potential against A549 lung cancer cells.
Summary of the invention:
The present invention discloses the anticancer screening of some new 2-(Bromosubstituted arylamino)-4-arylthiazoles against lung cancer cell line (A549). The compounds 1f, 2b, 2c, 2d, 2h and 3b were found to display significant potential than the standard drug, Carboplatin against the lung cancer cell line (A549).
Detailed description of the invention:
Anticancer activity evaluation
To explore the versatility of the synthesized compounds (Fig. 1), anti-cancer potential against lung cancer cell line has been evaluated.

Fig. 1. Various substituted 2-(Bromosubstituted arylamino)-4-arylthiazoles
All synthesized compounds were investigated for their anti-cancer potential against A549 lung cancer cells. The 50% inhibitory concentration of the compounds were calculated and compared with the standard anticancer drug, Carboplatin. The concentration dependent viability of the A549 cells on treatment with test compounds revealed the presence of anti-proliferative activity shown by all the compounds on lung cancer cells (Fig. 2). After screening, compounds 1f, 2b, 2c, 2d, 2f, and 3b-h showed the potent anti-proliferative property against A549 lung cancer cells with IC50 values <100 µM. Among all the compounds, 3f showed the highest activity followed by 2f and 3h on lung cancer cells with IC50 values 51.37 ± 2.9, 53.64 ± 6.5, and 55.92 ± 0.5 µM respectively. The compounds 1g, 2a, 2e, 2h, and 3a showed the cytotoxicity activity of IC50 values <200 µM. The cytotoxicity on Vero cells suggested that the compounds 3e (IC50=58.88 ± 1.7 µM), 3f (IC50=76.36 ± 2.0 µM), 3h (IC50=61.29 ± 1.2 µM), 3d (IC50=91.79 ± 1.7 µM), and 3c (IC50=69.84 ± 1.5 µM) possesses higher toxicity on kidney cells with IC50 values lower than 100 µM. Structure-activity relationship revealed that presence of 4-methoxyphenyl group at position-4 of thiazole ring enhnances the anti-cancer potency of thiazole derivatives irrespective of substitution at position-2 of thiazole ring. Moreover, as we move from 4-bromophenyl towards 2,4-dibromophenyl or 2,4,6-tribromophenyl substitution at amino group of thiazole ring cytotoxicity on vero cells and anti-proliferative potential on A549 cells decreases. All the compounds exhibited the anti-proliferative activity with good efficacy on lung cancer A549 cells. The compounds 1f, 2b, 2c, 2d, 2e, 3b, 3d, 3f, 3g, and 3h are highly anti-proliferative with less toxicity on Vero cells.
Table 1. Effect of compounds 1a-h; 2a-h; 3a-h on A549 lung adenocarcinoma and Vero cells IC50 (µM).
Compound IC50 (µM) ± SEM
A549 Cells IC50 (µM) ± SEM
Vero Cells
1a 327.63 ± 7.8 453.2 ± 3.1
1b 224.6 ± 7.0 569.6 ± 4.2
1c 316.62 ± 5.8 317.8 ± 2.1
1d 424.5 ± 4.7 297.33 ± 0.8
1e 207.03 ± 8.8 128.87 ± 0.6
1f 74.86 ± 3.4 139.8 ± 1.8
1g 193.6 ± 4.0 263.27 ± 3.8
1h 693 ± 1.6 452.2 ± 2.3
2a 134.07 ± 6.4 150.97 ± 1.0
2b 83.87 ± 3.7 646.93 ± 2.8
2c 64.90 ± 5.7 539 ± 2.5
2d 97.01 ± 4.3 737.53 ± 2.5
2e 174.1 ± 3.2 526.8 ± 2.6
2f 53.64 ± 6.5 73.73 ± 1.5
2g 275.4 ± 9.3 628.5 ± 2.3
2h 129.37 ± 8.0 1150.67 ± 4.4
3a 108.34 ± 7.5 93.16 ± 2.0
3b 89.09 ± 4.2 187 ± 2.7
3c 76.49 ± 2.7 69.84 ± 1.5
3d 89.90 ± 4.2 91.79 ± 1.7
3e 91.08 ± 0.8 58.88 ± 1.7
3f 51.37 ± 2.9 76.36 ± 2.0
3g 68.96 ± 5.4 154.2 ± 2.4
3h 55.92 ± 0.5 61.29 ± 1.2
Carboplatin 128.83 ± 2.0 155.9 ± 2.2

(A) (B)

(C) (D)

(E) (F)
Fig. 2. Percentage of viable A549 cells; (A) 1a-h and Carboplatin; (C) 2a-h and Carboplatin; (E) 3a-h and Carboplatin and vero cells; (B) 1a-h and Carboplatin; (D) 2a-h and Carboplatin; (F) 3a-h and Carboplatin on treatment with varying concentrations of test compounds

Outcome of the Invention:
Compounds 1f, 2b, 2c, 2d, 2h and 3b showed growth inhibitory effects on lung cancer cell line, with IC50 values 74.86 ± 3.4, 83.87 ± 3.7, 64.90 ± 5.7, 97.01 ± 4.3, 129.37 ± 8.0 & 89.09 ± 4.2, respectively. Therefore, compounds 1f, 2b, 2c, 2d, 2h and 3b have emerged as potential therapeutics for lung cancer in future.
Highlights of the Invention:
? Explored new 2-(Bromosubstituted arylamino)-4-arylthiazole derivatives 1f, 2b, 2c, 2d, 2h and 3b as new anticancer agents for lung cancer.
Experimental:
Anticancer activity
Cell Culture
A549 (Human lung adenocarcinoma cell) and Vero (African green kidney monkey cells) cells were cultured in Dulbecco’s Modified Eagle Medium (DMEM), GibcoTM media supplemented with 10% Fetal bovine serum (FBS), GibcoTM and 100 U/mL Pen-Strap antibiotics solution. Cells were maintained in CO2 incubator with continuous supply of 5% CO2 at 37?.
Cell viability assay
In-vitro cytotoxicity assay of the confluent adherent cells were harvested by 0.25% trypsin-EDTA solution. Cells with seeding density of 1 x 104 cells/well were seed on 96 well plates followed by incubation for 24 h for complete adherence. After incubation, the stock concentration of test compounds prepared in DMSO was added to the wells with concentration 1mM as initial concentration in initial wells with 0.2% DMSO as final concertation followed by 2-fold serial dilutions. The cells were treated with the compounds for 48 h in CO2 incubator followed by MTT assay. 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) salt was used to validate the cytotoxicity effect of the test compounds on A549 human lung cancer cells and Vero, normal kidney cells. On the day of MTT assay, the media was replaced with fresh media along with 0.5% MTT solution (5mg/mL stock in 1X PBS) followed by incubation for 3 h at 37?. The insoluble formazan crystal formed was dissolved in DMSO and incubated in shaker for 30 minutes at room temperature. The absorbance of 96 well plates were then read at 492 nm on ELISA microplate reader and percentage of cell viability was calculated.
, Claims:I/We claim
1. The compounds of the formula I, where Ar is C6H5, 4-F-C6H4, 4-Cl-C6H4, 4-Br-C6H4, 4-CH3-C6H4, 4-CH3O-C6H4, 4-NO2-C6H4, and Chromenyl as anticancer agents for lung cancer cell line (A549) at different concentrations.

2. Compounds as claimed in claim 1, wherein the said compound reduces cell viability of lung cancer cells (A549) up to 0.79% at 1000 µM at 48 h of treatment, whereas the Vero cells (normal cells) possessed viability up to 20.21%.
3. The compounds as claimed in claim 1, wherein the said compounds reduce cell viability of lung cancer cells (A549) up to 4.5% at 500 µM after 48 h treatment whereas the Vero cells (normal cells) possessed viability up to 19%.
4. The compounds as claimed in claim 1, wherein the said compounds reduce cell viability of lung cancer cells (A549) up to 45.78% at 31.25 µM after 48 h treatment whereas the Vero cells (normal cells) possessed viability up to 53.27%.