Benign Synthesis of Thiazolo-androstenone Derivatives as Potent Anticancer Agents

Efficient Synthesis of Thiazole-Fused Bisnoralcohol Derivatives as Potential Therapeutic Agents

Thiazole derivatives are known for a wide range of therapeutic properties. Bisnoralcohol is an inexpensive natural product obtained by the biodegradation of sterols. This article describes an efficient synthesis of a library of thiazole-fused bisnoralcohol derivatives. These novel compounds have been studied for their antineoplastic and antibacterial properties, which led to the discovery of hit compounds with therapeutic potential. The antibacterial compound is noncytotoxic and nonhemolytic against cancer cell lines and sheep red blood cells, respectively. Several of the antineoplastic compounds showed activity against human cancer cell lines with growth inhibition at submicromolar concentration.

Domino Reaction Protocol to Synthesize Benzothiophene-Derived Chemical Entities as Potential Therapeutic Agents

An efficient synthesis of 3-amino-2-formyl-functionalized benzothiophenes by a domino reaction protocol and their use to synthesize a library of novel scaffolds have been reported. Reactions of ketones and 1,3-diones with these amino aldehyde derivatives formed a series of benzothieno[3,2-b]pyridine and 3,4-dihydro-2H-benzothiopheno[3,2-b]quinolin-1-one, respectively. A plausible mechanism for the formation of fused pyridine derivatives by the Friedlander reaction has been elucidated by density functional theory (DFT) calculations. Furthermore, hydrazones were obtained by reacting the aldehyde functional group of benzothiophenes with different hydrazine derivatives. Preliminary screening of these compounds against several bacterial strains and cancer cell lines led to the discovery of several hit molecules. Hydrazone and benzothieno[3,2-b]pyridine derivatives are potent cytotoxic and antibacterial agents, respectively. One of the potent compounds effected ∼97% growth inhibition of the LOX IMVI cell line at 10 μM concentration.

Pyrazole: an emerging privileged scaffold in drug discovery

Pyrazole or 1H-pyrazole, a five-membered 1,2-diazole, is found in several approved drugs and some bioactive natural products. A myriad number of derivatives of this small molecule have been reported in clinical and preclinical studies for the potential treatment of several diseases. The number of drugs containing a pyrazole nucleus has increased significantly in the last 10 years. Some of the best-selling drugs in this class are ibrutinib, ruxolitinib, axitinib, niraparib and baricitinib, and are used to treat different types of cancers; lenacapavir to treat HIV; riociguat to treat pulmonary hypertension; and sildenafil to treat erectile dysfunction. Several aniline-derived pyrazole compounds have been reported as potent antibacterial agents with selective activity against methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci. Here, we discuss the pyrazole-derived drugs reported up to September 2023.

HFIP in Organic Synthesis

1,1,1,3,3,3-Hexafluoroisopropanol (HFIP) is a polar, strongly hydrogen bond-donating solvent that has found numerous uses in organic synthesis due to its ability to stabilize ionic species, transfer protons, and engage in a range of other intermolecular interactions. The use of this solvent has exponentially increased in the past decade and has become a solvent of choice in some areas, such as C-H functionalization chemistry. In this review, following a brief history of HFIP in organic synthesis and an overview of its physical properties, literature examples of organic reactions using HFIP as a solvent or an additive are presented, emphasizing the effect of solvent of each reaction.

Multicomponent synthesis of fully substituted thiazoles using glycine-based dithiocarbamates, acetic anhydride and nitroalkenes

Reaction of glycine-based dithiocarbamates with nitroalkenes in the presence of acetic anhydride was utilized for the synthesis of fully substituted 2-(alkylsulfanyl)-4-(nitroalkyl)-5-acyloxy-1,3-thiazoles. The reaction proceeds via the in situ formation of thiazol-5(4H)-one from glycine-based dithiocarbamates, followed by the Michael addition of this intermediate to nitroalkenes, aromatization, and esterification reaction cascade. This new one-pot three-component reaction afforded a diverse library of fully substituted thiazoles in high to excellent yields under solvent-free conditions.

Biological evaluation of antiproliferative and anti-invasive properties of an androstadiene derivative on human cervical cancer cell lines

Gynaecological cancers are leading cause of death: breast cancer is the most frequently diagnosed type of malignancies, and cervical neoplasms rank fourth for both incidence and mortality among women worldwide. In one of our previous studies, favourable antiproliferative and antimetastatic properties of a newly synthesized androstane derivative, 17APAD have been demonstrated on breast cancer cell lines with different expression patterns of hormone receptors. The aim of the current study was to investigate the antitumoral potential of this molecule in cervical cancer cell lines, including SiHa cells positive for human papilloma virus (HPV) type 16 and HPV-negative C33A cells. 17APAD exerted pronounced growth-inhibition (with IC₅₀ values ranging from 0.76 to 1.72 μM with considerable cancer selectivity), while cisplatin used as a reference agent yielded higher IC₅₀ values (ranging from 3.69 to 12.43) and less selectivity, as evidenced by MTT assay. The proapoptotic effect and morphological changes induced by 17APAD were detected by Hoechst 33258-propidium iodide or Annexin V-Alexa488-propidium iodide fluorescent double staining methods, supplemented with a caspase-3 activity assay to identify the mechanism behind the programmed cell death induced by 17APAD. Additionally, significant and concentration-dependent elevation of the ratio of cells in the G2/M phase, on the expense of G0/G1 phase, was observed after 48 h of exposure to 17APAD. Besides its potent antiproliferative properties against both cervical cancer cell lines, 17APAD elicited a remarkable inhibition of cell migration and invasion as detected in wound-healing and Boyden chamber assays, respectively. The mechanisms of action underlying the effects of 17APAD on cell proliferation and motility were independent of androgenic activity, as demonstrated by the Yeast Androgen Screen method. Our results provide new evidence for the proapoptotic and anti-invasive properties of 17APAD, suggesting that it is worth of further research, as a promising prototype for designing novel anticancer agents.

Synthesis of Chimeric Thiazolo-Nootkatone Derivatives as Potent Antimicrobial Agents

Nootkatone, an approved insecticide, is a well-known natural product from grapefruit. A series of fused-thiazole derivatives of nootkatone have been synthesized, and these new compounds were tested against several strains of bacteria. Some of these compounds are found to be potent antimicrobial agents against Staphylococcus aureus and Enterococcus faecium with minimum inhibitory concentration (MIC) values as low as 1.56 μg/mL. The lead compound is bactericidal and very potent against S. aureus persisters. These compounds are nontoxic to human cancer cell lines at 10 μm concentration.

Antimelanoma activities of chimeric thiazole-androstenone derivatives

The discovery of chimeric anti-melanoma agents is reported. These molecules are potent growth suppressors of melanoma cells in vitro with growth inhibition of 50% (GI₅₀) values as low as 1.32 µM. Compounds were more toxic to melanoma cells in vitro than commonly used anti-melanoma agent dacarbazine as measured by TUNEL assay. They induced both caspase-independent apoptosis evident by colocalization of TUNEL with endonuclease G (EndoG) and caspase-mediated apoptosis measured by colocalization of TUNEL with caspase-activated DNase (CAD). In addition, compounds 3 and 5 strongly induced oxidative injury to melanoma cells as measured by TUNEL colocalization with heme oxygenase-1 (HO1). Dacarbazine induced only caspase-independent apoptosis, which may explain why it is less cytotoxic to melanoma cells than compounds 3, 4 and 5.

Synthetic and Medicinal Perspective of Fused-Thiazoles as Anticancer Agents

BACKGROUND

Cancer is second leading disease after cardiovascular disease. Presently, Chemotherapy, Radiotherapy and use of chemicals are some treatments available these days. Thiazole and its hybrid compounds extensively used scaffolds in drug designing and development of novel anticancer agents due to their wide pharmacological profiles. Fused thiazole scaffold containing drugs are available in market as a promising group of anticancer agents.

METHODS

The detailed study has been done using different database that focused on potent thiazole hybrid compounds with anticancer activity. The literature included in this review is focused on novel fused thiazole derivatives exhibiting anticancer potency in last decade.

RESULTS

Literature suggested that thiazoles and its fused and linked congener serve excellent pharmacological profile as an anticancer agent. Various synthetic strategies for fused thiazole are also summarized in this article. Novel thiazole and its fused congener showed anticancer activity against various cancer cell lines.

INTERPRETATION

Thiazole is a promising scaffold reported in literature with broad range of biological activities. This article covers the thiazole compounds fused with other carbocyclic/heterocycle including benzene, imidazole, pyridine, pyrimidine, quinoline, phenothiazine, thiopyrano, steroids, pyrrole etc. with anticancer activity from last decades. Several inhibitors for breast cancer, colon cancer, melanoma cancer, ovarian cancer, tubulin cancer etc. were reported in this review. Thus, this review will definitely aid to develop a lead for the new selective anticancer agents in future.

Benign Synthesis of Fused-thiazoles with Enone-based Natural Products and Drugs for Lead Discovery

In an effort to synthesize a library of bioactive molecules, we present an efficient synthesis of fused-thiazole derivatives of natural products and approved drugs by using an environmentally usable solvent, acetic acid, and without any external reagent. Cholestenone, ethisterone, progesterone, and nootkatone-derived epoxyketones have been utilized to synthesize 50 novel compounds. The plausible mechanism of the reaction has been determined by theoretical calculation using M06-2X/6-31+G(d,p). These novel molecules have been tested against cancer cell lines and pathogenic bacterial strains. Several ethisterone-based fused-thiazole compounds are found to be potent growth inhibitors of cancer cell lines at submicromolar concentrations.

Synthesis and Antimicrobial Studies of 4-[3-(3-Fluorophenyl)-4-formyl-1H-pyrazol-1-yl]benzoic Acid and 4-[3-(4-Fluorophenyl)-4-formyl-1H-pyrazol-1-yl]benzoic Acid as Potent Growth Inhibitors of Drug-Resistant Bacteria

Microbial resistance to antibiotics is an urgent and worldwide concern. Several pyrazole-derived hydrazones were synthesized by using benign reaction conditions. Several of these molecules are potent growth inhibitors of drug-resistant strains of Staphylococcus aureus and Acinetobacter baumannii with minimum inhibitory concentration values as low as 0.39 μg/mL. Furthermore, these molecules are nontoxic to human cells at high concentrations. Some of these molecules were tested for their ability to disrupt the bacterial membrane by using the SYTO-9/propidium iodide (BacLight) assay.

Synthesis of Hydrazone Derivatives of 4-[4-Formyl-3-(2-oxochromen-3-yl)pyrazol-1-yl]benzoic acid as Potent Growth Inhibitors of Antibiotic-resistant Staphylococcus aureus and Acinetobacter baumannii

Microbial resistance to drugs is an unresolved global concern, which is present in every country. Developing new antibiotics is one of the guidelines of the Centers for Disease Control and Preventions (CDC) to combat bacterial resistance to drugs. Based on our lead molecules, we report the synthesis and antimicrobial studies of 27 new pyrazole derivatives. These new coumarin-pyrazole-hydrazone hybrids are readily synthesized from commercially available starting materials and reagents using benign reaction conditions. All the synthesized molecules were tested against 14 Gram-positive and Gram-negative bacterial strains. Several of these molecules have been found to be potent growth inhibitors of several strains of these tested bacteria with minimum inhibitory concentrations as low as 1.56 μg/mL. Furthermore, active molecules are non-toxic in in vitro and in vivo toxicity studies.

(E)-N′-(4-Fluorobenzylidene)-5-methyl-2-(pyridin-3-yl)thiazole-4-carbohydrazide

5-methyl-2-(pyridin-3-yl)-1,3-thiazole-4-carbohydrazide (1) on treatment with 4-fluorobenzaldehyde in presence of catalytic amount of acetic acid, accessed the target compound (2) with the yield of 79%. The target compound was confirmed by 1H-NMR, 13C-NMR, FT-IR and LCMS. In vitro antibacterial activity against Staphylococcus aureus (S. Aureus), Bacillus subtilis (B. subtilis), Escherichia coli (E. coli), and Pseudomonas aeruginosa (P. aeruginosa) were carried out and compound 2 showed promising activity against B. subtilis. In addition, compound 2 was analyzed for DNA binding study. It revealed that compound 2 has a promising affinity towards DNA double helix.

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.