Design, Synthesis, and Biological Evaluation of 2-(4-Aminophenyl)benzothiazole Analogues as Antiproliferative Agents

Novel Para-Aminobenzoic Acid Analogs and Their Potential Therapeutic Applications

A "building block" is a key component that plays a substantial and critical function in the pharmaceutical research and development industry. Given its structural versatility and ability to undergo substitutions at both the amino and carboxyl groups, para-aminobenzoic acid (PABA) is a commonly used building block in pharmaceuticals. Therefore, it is great for the development of a wide range of novel molecules with potential medical applications. Anticancer, anti-Alzheimer's, antibacterial, antiviral, antioxidant, and anti-inflammatory properties have been observed in PABA compounds, suggesting their potential as therapeutic agents in future clinical trials. PABA-based therapeutic chemicals as molecular targets and their usage in biological processes are the primary focus of this review study. PABA's unique features make it a strong candidate for inclusion in a massive chemical database of molecules having drug-like effects. Based on the current literature, further investigation is needed to evaluate the safety and efficacy of PABA derivatives in clinical investigations and better understand the specific mechanism of action revealed by these compounds.

Synthetic Approaches to Biologically Active C-2-Substituted Benzothiazoles

Numerous benzothiazole derivatives are used in organic synthesis, in various industrial and consumer products, and in drugs, with a wide spectrum of biological activity. As the properties of the benzothiazole moiety are strongly affected by the nature and position of substitutions, in this review, covering the literature from 2016, we focus on C-2-substituted benzothiazoles, including the methods of their synthesis, structural modification, reaction mechanisms, and possible pharmacological activity. The synthetic approaches to these heterocycles include both traditional multistep reactions and one-pot atom economy processes using green chemistry principles and easily available reagents. Special attention is paid to the methods of the thiazole ring closure and chemical modification by the introduction of pharmacophore groups.

Synthesis of biologically active derivatives of 2-aminobenzothiazole

The minireview considers the current trends in the synthesis of some biologically active compounds based on 2-aminobenzothiazole. The presented information covers publications of the last five years.

Radical Arylation of Triphenyl Phosphite Catalyzed by Salicylic Acid: Mechanistic Investigations and Synthetic Applications

A straightforward and scalable methodology to synthesize diphenyl arylphosphonates at 20 °C within 1-2 h is reported using inexpensive SA as the catalytic promoter of the reaction. Mechanistic investigations suggest that the reaction proceeds via radical-radical coupling, consistent with the so-called persistent radical effect. The reaction tolerated a wide range of functional groups and heteroaromatic moieties. The synthetic usefulness and the unique reactivity of the obtained phosphonates were demonstrated in different one-step transformations.

2-substituted benzothiazoles as antiproliferative agents: Novel insights on structure-activity relationships

Given the wide spectrum of biological activities, benzothiazoles represent privileged scaffolds in medicinal chemistry, useful in drug discovery programs to modulate biological activities of lead compounds. A large body of knowledge about benzothiazoles has been reported in scientific literature, describing their antimicrobial, anticonvulsant, neuroprotective, anti-inflammatory, and antiproliferative effects. This review summarizes the results obtained in the structure-activity relationship studies on antiproliferative benzothiazoles, focusing on 2-substituted derivatives and on mechanism of action responsible for the antitumor effects of this class of compounds.

Novel benzimidazole-triazole hybrids as apoptosis inducing agents in lung cancer: Design, synthesis, 18F-radiolabeling & galectin-1 inhibition studies

In this study, we have synthesized a new series of benzimidazole-triazole hybrids as galectin-1 (gal-1) mediated apoptosis-inducing agents, and evaluated for their potential anticancer activity against a panel of human cancer cell lines viz. breast cancer (MCF-7 and MDA-MB-231) lung cancer (A-549 and NCI-H460), and human keratinocyte cancer (HaCaT), using MTT assay. The target compound 7c exhibited an excellent growth inhibition against lung cancer (A-549 and NCI-H460) cells with an IC₅₀ value of 0.63 ± 0.21 µM, and 0.99 ± 0.01 µM respectively. The target compound 7c also showed a significant growth inhibition against breast cancer (MCF-7 and MDA-MB-23) with an IC₅₀ value of 1.3 ± 0.18 µM, and 0.94 ± 0.02 µM respectively. In addition, the radiochemical synthesis has been performed using fluorine-18 radionuclide in the GE Tracer-lab FX2N module to prove the target compound 7c as a PET imaging agent. In the final stage, the ¹⁸F-7c target compound was successfully purified with 60% ethanol in water. The radiochemical purity was achieved >95% using HPLC, and the residual solvent DMF limit was around 78 ± 3 ppm confirmed by GC analysis. Further, the apoptosis induction by 7c in lung cancer (A-549) cells was confirmed as a result of the decrease in MMP levels, increased percentage of apoptotic cells, and sub G1 phase arrest by JC-1 staining, DAPI staining, annexin V-FITC/PI, and flow cytometric analysis. In addition, the target compound 7c significantly reduced the gal-1 protein levels in a dose-dependent manner as confirmed by ELISA studies. The protein binding studies like Surface Plasmon Resonance (SPR) and Fluorescence Spectroscopy (FS) studies indicated that the target compound 7c is capable of binding to gal-1 with an equilibrium constant (K_D) value of 1.19E-06 M, and binding constant (K_a) of 9.5 × 10³ M^-1 respectively. The in-silico computational studies also revealed possible interactions and pharmacokinetic properties (ADMET) of compound 7c with the binding domain of gal-1. Therefore, the novel benzimidazole-triazole hybrids as apoptosis-inducing agents in lung cancer would be potential cytotoxic and PET imaging agents via gal-1.