Synthesis of hydrazinyl-thiazole ester derivatives, in vitro trypanocidal and leishmanicidal activities

Aim: To synthesize novel more potent trypanocidal and leishmanicidal agents. Methods: Hantzsch's synthetic strategy was used to synthesize 1,3-thiazole-4-carboxylates and their N-benzylated derivatives. Results: 28 new thiazole-carboxylates and their N-benzylated derivatives were established to test their trypanocidal and leishmanicidal activities. From both series, compounds 3b, 4f, 4g, 4j and 4n exhibited a better or comparable trypanocidal profile to benznidazole. Among all tested compounds, 4n was found to be the most potent and was better than benznidazole. Conclusion: Further variation of substituents around 1,3-thiazole-4-carboxylates and or hydrazinyl moiety may assist in establishing better and more potent trypanocidal and leishmanicidal agents.

Facile Synthesis and DFT Analysis of Novel Thiazole-Based Hydrazones: An Experimental and Theoretical Perspective

Hydrazone compounds with remarkable nonlinear optical (NLO) properties were found with vast applications due to their cost-effective synthesis and greater stability. Therefore, we synthesized hydrazone scaffolds (TCAH1-TCAH8) by condensation reaction, and their structural confirmation was accomplished with spectroscopic methods (1H-, 13C-NMR, and HRMS). Quantum chemical calculations were also performed at B3PW91/6-311G(d,p) functional of DFT to explore electronic, structural, and chemical properties. To understand the NLO responses of afore-said chromophores, various kinds of analyses such as natural bonding orbitals (NBOs), frontier molecular orbitals (FMOs), UV-vis analysis, and density of states (DOS) were performed. Findings showed that the HOMO-LUMO energy gap in TCAH8 (3.595 eV) was found to be lower than the TCAH1-TCAH7 (4.123-3.932 eV) with a large red shift which leads to a substantial NLO response. Furthermore, strong intramolecular interactions showed the highest stabilization energy (24.1 kcal mol-1) for TCAH8 in the NBO transitions, combined with the least binding energy. The significant NLO response of TCAH4 was explored with ⟨α⟩, βtot, and ⟨γ⟩ values as 5.157 × 10-23, and 2.185 × 10-29, and 2.753 × 10-34 esu, respectively, among the entitled compounds. The recent findings may inspire scientists to develop extremely effective NLO materials for forthcoming hi-tech applications.

Synthesis of hydrazinylthiazole carboxylates: a mechanistic approach for treatment of diabetes and its complications

Aim: The deaths of thousands of people and millions affected by diabetes mellitus triggered us to look for alternative possible solutions to cure diabetes and its complications. Materials & methods: A series of hydrazinylthiazole carboxylates (3a-n) was prepared by cyclocondensation reaction of thiosemicarbazones with ethyl 2-chloroacetoacetate. These compounds were screened for antidiabetic potential through α-amylase inhibition, antiglycation and antioxidant assays. Results & conclusion: Most of the compounds exhibited a promising antidiabetic property. Compounds 3e and 3h showed excellent α-amylase and glycation inhibition properties. The hemolytic assay indicated that all compounds are biocompatible. Docking studies carried out on α-amylase target showed correlation between in vitro inhibition and binding energy.

4-Adamantyl-(2-(arylidene)hydrazinyl)thiazoles as potential antidiabetic agents: experimental and docking studies

Aim: To develop an efficient and cost-effective antidiabetic agent. Methods: A simple and convenient Hantzsch synthetic strategy was used to prepare 4-adamantyl-(2-(arylidene)hydrazinyl)thiazoles. Results: Fifteen newly established structures of 4-adamantyl-(2-(arylidene)hydrazinyl)thiazoles were tested for their α-amylase, antiglycation and antioxidant activities. Almost all tested compounds showed excellent α-amylase inhibition. Compounds 3a and 3j exhibited the highest potency, with IC₅₀ values of 16.34 ± 2.67 and 16.64 ± 1.12 μM, respectively. Compounds 3c and 3i exhibited comparable antiglycation potential with the standard, aminoguanidine. The antioxidant potential of compound 3g was found to be excellent, with an IC₅₀ value of 28.19 ± 0.2563 μM. The binding interactions of compound 3a (binding energy = -8.833 kcal/mol) with human pancreatic α-amylase identified 3a as a potent α-amylase inhibitor. Conclusion: Enrichment of established structures with more electron-donating functionalities may assist/lead to the development of more potent antidiabetic drugs.

Synthesis of Fluorinated Hydrazinylthiazole Derivatives: A Virtual and Experimental Approach to Diabetes Management

A novel series of fluorophenyl-based thiazoles was synthesized following the Hanztsch method. All of the compounds were initially verified with physical parameters (color, melting point, retardation factor (R _f)), which were further confirmed by several spectroscopic methods, including ultraviolet-visible (UV-visible), Fourier-transform infrared (FTIR), ¹H, ¹³C, ¹⁹F NMR, and high-resolution mass spectrometry (HRMS). The binding interactions of all compounds were studied using a molecular docking simulation approach. Furthermore, each compound was evaluated for its alpha(α)-amylase, antiglycation, and antioxidant potentials. The biocompatibility of all compounds was checked with an in vitro hemolytic assay. All synthesized scaffolds were found biocompatible with minimal lysis of human erythrocytes as compared to the standard Triton X-100. Among the tested compounds, the analogue 3h (IC₅₀ = 5.14 ± 0.03 μM) was found to be a highly potent candidate against α-amylase as compared to the standard (acarbose, IC₅₀ = 5.55 ± 0.06 μM). The compounds 3d, 3f, 3i, and 3k exhibited excellent antiglycation inhibition potential with their IC₅₀ values far less than the standard amino guanidine (IC₅₀ = 0.403 ± 0.001 mg/mL). The antidiabetic potential was further supported by docking studies. Docking studies revealed that all synthesized compounds exhibited various interactions along enzyme active sites (pi-pi, H-bonding, van der Waals) with varied binding energies.

Synthesis, characterization and exploration of photovoltaic behavior of hydrazide based scaffolds: a concise experimental and DFT study

Solar energy being a non-depleting energy resource, has attracted scientists' attention to develop efficient solar cells to meet energy demands. Herein, a series of hydrazinylthiazole-4-carbohydrazide organic photovoltaic compounds (BDTC1-BDTC7) with an A1-D1-A2-D2 framework was synthesized with 48-62% yields, and their spectroscopic characterization was accomplished using FT-IR, HRMS, ¹H and ¹³C-NMR techniques. Density functional theory (DFT) and time dependent DFT analyses were performed utilizing the M06/6-31G(d,p) functional to calculate the photovoltaic and optoelectronic properties of BDTC1-BDTC7via numerous simulations of the frontier molecular orbitals (FMOs), transition density matrix (TDM), open circuit voltage (V _oc) and density of states (DOS). Moreover, the conducted analysis on the FMOs revealed efficient transference of charge from the highest occupied to the lowest unoccupied molecular orbitals (HOMO → LUMO), further supported by TDM and DOS analyses. Furthermore, the values of binding energy (E _b = 0.295 to 1.150 eV), as well as reorganization energy of the holes (-0.038-0.025 eV) and electrons (-0.023-0.00 eV), were found to be smaller for all the studied compounds, which suggests a higher exciton dissociation rate with greater hole mobility in BDTC1-BDTC7. V _oc analysis was accomplished with respect to HOMO_PBDB-T-LUMO_ACCEPTOR. Among all the synthesized molecules, BDTC7 was found to have a reduced band gap (3.583 eV), with a bathochromic shift and absorption maximum at 448.990 nm, and a promising V _oc (1.97 V), thus it is regarded as a potential candidate for high performance photovoltaic applications.

Design, and synthesis of selectively anticancer 4-cyanophenyl substituted thiazol-2-ylhydrazones

Cyclization of substituted thiosemicarbazones with α-bromo-4-cyanoacetophenone allows rapid single-step sustainable syntheses of 4-cyanophenyl-2-hydrazinylthiazoles libraries (30 examples, 66-79%). All show anticancer efficacy against HCT-116 and MCF-7 carcinoma cell lines with the majority being more active than cisplatin positive controls. The compounds 2-(2-(2-hydroxy-3-methylbenzylidene)hydrazinyl)-4-(4-cyanophenyl)thiazole (3f) and 2-(2-((pentafluorophenyl)methylene)-hydrazinyl)-4-(4-cyanophenyl)thiazole (3a') show optimal GI50 values (1.0 ± 0.1 μM and 1.7 ± 0.3 μM) against MCF-7 breast cancer cells. Against colorectal carcinoma HCT-116 cells, (2-(2-(3-bromothiophen-2-yl)methylene)hydrazinyl)-4-(4-cyanophenyl)thiazole (3b'), 2-(2-(2-hydroxy-3-methylbenzylidene)hydrazinyl)-4-(4-cyanophenyl)thiazole (3f), 2-(2-(2,6-dichlorobenzylidene)hydrazinyl)-4-(4-cyanophenyl)thiazole (3n) and 2-(2-(1-(4-fluorophenyl)ethylidene)hydrazinyl)-4-(4-cyanophenyl)thiazole (3w) are the most active (GI50 values: 1.6 ± 0.2, 1.6 ± 0.1, 1.1 ± 0.5 and 1.5 ± 0.8 μM respectively). Control studies with MRC-5 cells indicate appreciable selectivity towards the cancer cells targeted. Significant (p < 0.005) growth inhibition and cytotoxicity effects for the thiazoles 3 were corroborated by cell count and clonogenic assays using the same cancer cell lines at 5 and 10 μM agent concentrations. Cell cycle, caspase activation and Western blot assays demonstrated that compounds 3b' and 3f induce cancer cell death via caspase-dependent apoptosis. The combination of straight forward synthesis and high activity makes the thiazoles 3 an interesting lead for further development.

Synthesis of Arylidenehydrazinyl-4-methoxyphenylthiazole Derivatives: Docking Studies, Probing Type II Diabetes Complication Management Agents

Thiazole has been a key scaffold in antidiabetic drugs. In quest of new and more effective drugs a simple, efficient, high yielding (67-79%) and convenient synthesis of arylidenehydrazinyl-4-methoxyphenyl)thiazoles is accomplished over two steps. The synthesis involved the condensation of aryl substituted thiosemicarbazones and 2-bromo-4-methoxyacetophenone in absolute ethanol. The structures of the resulting thiazoles are in accord with their UV-Vis, FT-IR, 1 H-, 13 C-NMR and HRMS data. All compounds were evaluated for alpha(α)-amylase inhibition potential, antiglycation, antioxidant abilities and biocompatibility. The compounds library identified 2-(2-(3,4-dichlorobenzylidene)hydrazinyl)-4-(4-methoxyphenyl)thiazole as a lead molecule against α-amylase inhibition with an IC 50 of 5.75±0.02 µM. α-Amylase inhibition is also supported by molecular docking studies against amylase. All the obtained thiazoles also showed promising antiglycation activity with 4-(4-methoxyphenyl)-2-(2-(2-(trifluoromethyl)benzylidene)hydrazinyl)thiazole exhibiting the best inhibition (IC 50 = 0.383±0.001 mg/mL) compared to control. The tested compounds are also biocompatible at the concentration used i.e. 10 µM.

Phase II study of gemcitabine concurrent with radiation in locally advanced squamous cell carcinoma of head and neck: Trial of the Cancer Research Group Pakistan

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Background: The optimum radiosensitizing dose and schedule of gemcitabine for squamous cell carcinoma of head and neck are not known. The objectives of this study were to evaluate the efficacy and toxicity of weekly gemcitabine as a radiosensitizer concurrent with radical radiotherapy in locally advanced head and neck cancer. Method: Thirty-nine patients with stage III or IV B inoperable carcinoma of head and neck were enrolled. Eligible patients had histopathologically confirmed squamous cell carcinoma with age between 18–70 years. Patients had a KPS >70 with an adequate marrow, hepatic and renal function. No prior chemotherapy or radiotherapy was allowed. Patients with nasopharyngeal, glottic or sub-glottic cancer were excluded. Gemcitabine 150 mg/m2 or a total dose not exceeding 200 mg was given on day 1,8,15,22,29, and 36 during radiation treatment. Gemcitabine was infused in 200 ml of normal saline in 2 hours and radiation was delivered two hours after the completion of gemcitabine infusion. Conventional fractionation was used to deliver a total dose of 66 Gy. CTC version 2.0 of NCI and RTOG/EORTC Late Radiation Morbidity Scoring Scheme were used for evaluation of toxicity and RECIST was used for response evaluation. Results: Only 35 patients were considered evaluable for response. Complete response was seen in 8 (22.9%) (95% CI; 10.4–40.1%), partial response in 25 (71.4%), with an overall response rate of 94.3% (95% CI; 80.8–99.3%). All the thirty-nine patients were evaluable for toxicity. Grade 3 and 4 mucositis was seen in 28 (71.8%) and 2 (5.1%) patients respectively. Grade 3 pharyngeal toxicity was seen in 6 (15.4%). One patient developed pharyngo-cutaneous fistula. Despite vigorous symptomatic and supportive care acute toxicities led to treatment interruption in 16 (41%) of patients. Conclusion: Weekly gemcitabine at a dose of 150mg/m2 concurrent with radiation therapy gives a high overall response rate and a high rate of acute toxicity.

No significant financial relationships to disclose.