Synthesis and antiproliferative activity of D-ring substituted steroidal benzamidothiazoles

Development and therapeutic potential of 2-aminothiazole derivatives in anticancer drug discovery

Currently, the development of anticancer drug resistance is significantly restricted the clinical efficacy of the most commonly prescribed anticancer drug. Malignant disease is widely prevalent and considered to be the major challenges of this century, which concerns the medical community all over the world. Consequently, investigating small molecule antitumor agents, which could decrease drug resistance and reduce unpleasant side effect is more desirable. 2-aminothiazole scaffold has emerged as a promising scaffold in medicinal chemistry and drug discovery research. This nucleus is a fundamental part of some clinically applied anticancer drugs such as dasatinib and alpelisib. Literature survey documented that different 2-aminothiazole analogs exhibited their potent and selective nanomolar inhibitory activity against a wide range of human cancerous cell lines such as breast, leukemia, lung, colon, CNS, melanoma, ovarian, renal, and prostate. In this paper, we have reviewed the progresses and structural modification of 2-aminothiazole to pursuit potent anticancers and also highlighted in vitro activities and in silico studies. The information will useful for future innovation. Representatives of 2-aminothiazole-containing compounds classification.

2-Aminothiazole: A privileged scaffold for the discovery of anti-cancer agents

Cancer has been the second heath killer being next only to cardiovascular diseases in human society. Although many efforts have been taken for cancer therapy and many achievements have been yielded in the diagnosis and treatment of cancer, the current first-line anti-cancer agents are insufficient owing to the emergence of multi-drug resistance and side effects. Therefore, it is urgent to develop new anti-cancer agents with high activity and low toxicity. 2-Aminothiazole is a class of important scaffold which widely distributes in many natural and synthetic compounds with many pharmacological effects including the potential anti-cancer activity. In this review, we summarized the recent progress of 2-aminothiazole as a privileged scaffold for the discovery of anti-cancer agents based on biological targets, such as tubulin protein, histone acetylase/histone deacetylase (HAT/HDAC), phosphatidylinositol 3-kinases (PI3Ks), Src/Abl kinase, BRAF kinase, epidermal growth factor receptor (EGFR) kinase and sphingosine kinase (SphK), and also investigated the structure-activity relationships (SARs) of most compounds. It is believed that this review could be helpful for medicinal chemists in the discovery of more anti-cancer agents bearing 2-aminothiazole scaffold with excellent activity and high therapeutic index.

Thiazole-containing compounds as therapeutic targets for cancer therapy

In the last few decades, considerable progress has been made in anticancer agents development, and several new anticancer agents of natural and synthetic origin have been produced. Among heterocyclic compounds, thiazole, a 5-membered unique heterocyclic motif containing sulphur and nitrogen atoms, serves as an essential core scaffold in several medicinally important compounds. Thiazole nucleus is a fundamental part of some clinically applied anticancer drugs, such as dasatinib, dabrafenib, ixabepilone, patellamide A, and epothilone. Recently, thiazole-containing compounds have been successfully developed as possible inhibitors of several biological targets, including enzyme-linked receptor(s) located on the cell membrane, (i.e., polymerase inhibitors) and the cell cycle (i.e., microtubular inhibitors). Moreover, these compounds have been proven to exhibit high effectiveness, potent anticancer activity, and less toxicity. This review presents current research on thiazoles and elucidates their biological importance in anticancer drug discovery. The findings may aid researchers in the rational design of more potent and bio-target specific anticancer drug molecules.

Synthesis and evaluation of novel D-ring substituted steroidal pyrazolines as potential anti-inflammatory agents

To identify new potential anti-inflammatory agents, a number of novel steroidal derivatives with nitrogen heterocyclic side chains 4a-4l were synthesized and evaluated for their anti-inflammatory effects in activated RAW 264.7 macrophage cells. The synthesis scheme involves two steps, Claisen-Schmidt condensation with the corresponding pregnenolone and aromatic aldehydes as the first step followed by nucleophilic addition of thiosemicarbazide across an α, β-unsaturated carbonyl as a later step. Compound structures were confirmed by ¹H NMR, ¹³C NMR, HRMS, and IR. The compounds were assayed to test their anti-inflammatory effects in activated RAW 264.7 cells. Compound 4g, 3β-hydroxy-pregn-5-en-17β-yl-5'-(m-fluorophenyl)-4', 5'-dihydro-1'-carbothioic acid amido pyrazole, was identified as the most potent anti-inflammatory agent of the analysed compounds, with an IC₅₀ value of 0.86 µM on nitric oxide (NO) production in lipopolysaccharide (LPS)-induced RAW 264.7 cells for 24 h compared to dexamethasone (IC₅₀ = 0.62 µM) and low cytotoxicity against RAW 264.7 cells. Compound 4g significantly inhibited NO produced by LPS-induced RAW 264.7 cells. Further studies showed that compound 4g markedly inhibited the expression of pro-inflammatory factors, including inducible nitric oxide synthase (iNOS), interleukin-6 (IL-6), tumour necrosis factor-α (TNF-α), and cyclooxygenase-2 (COX-2) in LPS-induced RAW 264.7 cells. These results indicate that derivatives bearing pyrazoline structure might be considered for further research and scaffold optimization in designing anti-inflammatory drugs and compound 4g might be a promising therapeutic anti-inflammatory drug candidate.

Hexafluoroisopropanol-Mediated Domino Reaction for the Synthesis of Thiazolo-androstenones: Potent Anticancer Agents

A cascade reaction of thioamides with 6β-bromoandrostenedione in hexafluoroisopropanol formed substituted thiazolo-androstenones. This is a simple and mild protocol to synthesize novel molecules by using readily available reagents and substrates. Feasibility of the reaction has been rationalized by density functional theory calculations. Moreover, these compounds are potent growth inhibitors of colon, central nervous system, melanoma, ovarian, and renal cancer cell lines with 50% growth inhibition values as low as 1.04 μM.

Synthesis and cytotoxic activity of novel steroidal derivatives containing a [1,2,4]triazolo[1,5-a]pyrimidine ring

The synthesis of steroidal derivatives containing [1,2,4]triazolo[1,5- a]pyrimidine derived from progesterone is described. The Claisen condensations of Δ1,4-pregnadien-3,20-dione and 4-chloro-Δ1,4-pregnadien-3,20-dione with dimethyl oxalate afforded 21-methoxalylpregn-1,4-diene-3,20-dione and 4-chloro-21-methoxalylpregn-1,4-diene-3,20-dione, respectively. Furthermore, the reactions of these compounds with 3-amino-1,2,4-triazole yielded the corresponding [1,2,4]triazolo[1,5- a]pyrimidine derivatives. The newly synthesised compounds were evaluated in vitro by means of sulforhodamine B assays for antiproliferative activity against HeLa and MCF-7 cells.