Fe(iii)-Catalyzed synthesis of steroidal imidazoheterocycles as potent antiproliferative agents

Design and synthesis of phosphoryl-substituted steroidal pyridazines (Pho-STPYRs) as potent estrogen receptor alpha inhibitors: targeted treatment of hormone-dependent breast cancer cells

Estrogen receptor alpha (ERα) is an important target for the discovery of new therapeutic drugs against hormone-dependent breast cancer. A series of phosphoryl-substituted steroidal pyridazines (Pho-STPYRs) were synthesized and biologically evaluated as potent ERα inhibitors. Pho-STPYRs showed cytotoxicity against breast cancer cells with IC50 values of 5.9 μM and higher. Pho-STPYRs 33 and 34 [IC50 (MCF7) = 6.5 and 5.9 μM, respectively] were found to block the expression of ERα, the main driver of breast cancer growth, and modulate the ERK, cyclin D1, and CDK4 pathways. Compound 34 showed selectivity, anti-estrogenic potency and high antiproliferative efficacy in combination with the AKT inhibitor. Molecular docking was used to more accurately define the binding mode of lead compounds 33 and 34 to ERα. The selectivity analysis showed that lead compounds 33 and 34 produce no effects on cytochromes P450, including CYP7A1, CYP7B1, CYP17A1, CYP19A1, and CYP21A2. In a word, Pho-STPYRs 33 and 34 are promising ERα inhibitors for the treatment of hormone-dependent breast cancer.

Exploration and biological evaluation of 20-vinyl pregnenes: A step forward toward selective modulators of the estrogen receptor α signaling for breast cancer treatment

A series of D-ring modified steroids bearing a vinyl ketone pendant were synthesized and evaluated for antiproliferative activity against breast cancer cell line and cytochromes P450. The lead compound, 21-vinyl 20-keto-pregnene (2f) (IC50 = 2.4 µM), was shown to be a promising candidate for future anticancer drug design, particularly against estrogen receptor α (ERα)-positive breast cancer. The lead compound was found to have a significant effect on the signaling pathways in parental and 4-hydroxytamoxifen-resistant cells. Compound 2f modulated the ERK, cyclin D1, and CDK4 pathways and blocked the expression of ERα, the main driver of breast cancer growth. Compound 2f significantly reduced 17β-estradiol-induced progesterone receptor expression. Accumulation of cleaved poly(ADP-ribose) polymerase in cells treated with compound 2f indicated induction of apoptosis. The selectivity analysis showed that lead compound 2f produces no significant effects on cytochromes P450, CYP19A1, CYP21A2, and CYP7B1.

Synthesis and biological activities of bicyclic pyridines integrated steroid hybrid

Reports on structural modification of heterosteroids through various reactions, and developed synthetic routes have considerably increased over the last decade. The present review encompasses the applicable approaches dealing with the utility of reactive moieties in various steroids for the synthesis of fused bicyclic pyridines, and binary bicyclic pyridines all over the years. The different sections include the synthesis of steroids-fused, and binary quinolines, pyridopyrimidines, imidazopyridines, spirocyclic imidazopyridines, pyrazolopyridines, thienopyridines, pyridinyl-thiazoles, and tetrazolopyridine hybrids, as well as, the diverse biological applications of these heterocyclic steroids. The researchers' interest was principally focused on investigating the flexibility of synthetic strategies for various derivatives of natural steroids and building proposals based on heterocyclic steroids for drug discovery, biological assessments, and synthetic applications.

Synthesis and site selective C-H functionalization of imidazo-[1,2-a]pyridines

Imidazo[1,2-a]pyridine has attracted much interest in drug development because of its potent medicinal properties, therefore the discovery of novel methods for its synthesis and functionalization continues to be an exciting area of research. Although transition metal catalysis has fuelled the most significant developments, extremely beneficial metal-free approaches have also been identified. Even though pertinent reviews focused on imidazo[1,2-a]pyridine synthesis, properties (physicochemical and medicinal), and functionalization at the C3 position have been published, none of these reviews has focused on the outcomes obtained in the field of global ring functionalization. We wish here to describe a brief synthesis and an overview of all the functionalization reactions at each carbon atom, viz, C2, C3, C5, C6, C7 and C8 of this scaffold, divided into sections based on site-selectivity and the type of functionalization methods used.

Discovery of highly potent proapoptotic antiestrogens in a series of androst-5,16-dienes D-modified with imidazole-annulated pendants

Heterocyclic derivatives of steroid hormones are potent anticancer agents, which are used in the chemotherapy of breast and prostate cancers. Here, we describe a novel series of androstenes, D-modified with imidazole-annulated pendants, with significant anticancer activity. Novel C17-linked imidazole-annulated heterocyclic derivatives of dehydropregnenolone acetate were synthesized by the cyclocondensation with amidines using 3β-acetoxy-21-bromopregna-5,16-dien-20-one as the substrate. The antiproliferative potency of all the synthesized compounds was evaluated against human prostate (22Rv1) and human breast (MCF7) cancer cell lines and cytochromes P450. The lead compound, imidazo[1,2-a]pyridine derivative 3h, was revealed to be a promising candidate for future anticancer drug design, particularly against ERα-positive breast cancer. Lead compound 3h was found to be selective against MCF7 cells with IC₅₀ of 0.1μM and to act as both a potent selective agent blocking estrogen receptor α, which is involved in the stimulation of breast cancer growth, and an effective apoptosis inducer. The potential ability of compound 3h to bind to ERα was studded using molecular docking and molecular dynamics simulation. The selectivity analysis showed that lead steroid 3h produces no effects on cytochromes P450 CYP17A1, CYP7A1, and CYP21A2.

Recent advances in carbosilylation of alkenes and alkynes

Alkene and alkyne difunctionalization is a flexible process that allows the construction of two functional groups simultaneously in one step. On the other hand, carbosilylation, an ingenious difunctionalization pathway to concurrently incorporate both a silyl group and an organic functional group (alkyl, (hetero)aryl, alkenyl, alkynyl and allenyl) across a carbon-carbon multiple-bond system, is achieving immense interest in recent days. This review article provides a decade's update on the discoveries and developments in the synthesis of carbosilylated products from two very important carbon-carbon unsaturated substrates, alkenes and alkynes.

Silica supported lanthanum trifluoroacetate and trichloroacetate as an efficient and reusable water compatible Lewis acid catalyst for synthesis of 2,4,5-triarylimidazoles via a solvent-free green approach

In the present research article, we have developed solid heterogenous silica supported lanthanum trifluoroacetate and trichloroacetate as green Lewis acid catalysts. These catalysts were synthesized by a novel, simple, cheap, clean, and environment friendly method. The physicochemical properties of the prepared catalysts were well studied and characterized by sophisticated spectroscopic techniques such as FTIR, TGA, XRD, EDX, SEM, TEM and BET analysis. The catalyst was utilized in the synthesis of arylimidazole derivatives via green protocols under solvent-free conditions at 70 °C with a higher yield, mild reaction conditions and a short reaction time. The catalyst works superiorly in water as well as in various organic solvents as a reusable and easily recoverable catalyst.

Ortho C-H Functionalizations of 2-Aryl-2H-Indazoles

C-H Functionalization is ubiquitously considered as a powerful, efficient and handy tool for installing various functional groups in complex organic heterocycles in an easier and step-economic way. Similarly, indazole is endowed as a potent heterocycle and is eminent for its profound impact in biological, medicinal and industrial chemistry. In this scenario, C-H functionalization at the selective ortho position of 2-arylindazole in assistance of a metal catalyst is also becoming an appealing approach in synthetic organic chemistry. This review addressed the recent findings and developments on ortho C-H functionalization of 2-aryl-2H-indazazoles with literature coverage extending from 2018 to May 2022.

Asymmetric C(sp3)-H borylation: an update

Chiral organoboronates have emerged as a key intermediate in the development of pharmaceuticals and materials science. Therefore, several attempts have been made to design various synthetic methods to easily furnish these compounds during the past few decades. Inter alia, asymmetric catalysis has been increasing rapidly as a viable, practical and beneficial strategy for their preparation. In this respect, recent years have witnessed significant progress in aliphatic C-H borylation as the generated carbon-boron bonds are largely utilized to produce other carbon-carbon, carbon-nitrogen and carbon-oxygen bonds. This review presents a detailed overview and analysis of transition metal-catalyzed asymmetric C(sp³)-H borylation strategies. Overall, it assembles all the recent developments in this particular synthetic avenue up to March 2022.

Synthesis of Unsymmetrical Biheteroarenes via Dehydrogenative and Decarboxylative Coupling: a Decade Update

The design and development of robust and efficient methods for installing one heterocycle with another is endowed as a ubiquitous and powerful synthetic strategy to access complex organic biheterocycles in recent days due to their pervasive applications in medicinal as well as material chemistry. This perspective presents an overview on the recent findings and developments for the synthesis of unsymmetrical biheteroarenes via dehydrogenative and decarboxylative couplings with literature coverage mainly extending from 2011 to 2021. For simplification of the readers, the article has been subcategorized based on the catalysts used in the reactions.

Ortho C-H Functionalization of 2-Arylimidazo[1,2-a]pyridines

C-H activation and functionalization is quite promising in recent days as the strategy offers a go-to general method for different bond formations and hence grants synthetic versatility. At the same time, imidazopyridine, a fused bicycle of imidazole moiety with pyridine ring, has a profound impact due to its ubiquitous and prodigious application in medicinal as well as material chemistry. The presence of N-1 atom in 2-arylImidazo[1,2-a]pyridine facilitates the coordination with metal catalysts leading to the formation of ortho-substituted products. This review summarizes all the articles on ortho C-H functionalization of 2-arylImidazo[1,2-a]pyridines published till August 2021.

Manganese-catalyzed dehydrogenative Csp3-Csp2 coupling of imidazo[1,2-a]pyridines with methyl ketones

A Mn(ii)-catalyzed efficient C-H alkylation of imidazoheterocycles with methyl ketones has been developed via dehydrogenative C(sp3)-C(sp2) coupling which can serve as a novel approach toward hydrocarboxylated imidazolopyridines. The merit of this strategy is illustrated by excellent functional group tolerance and the use of cheap and readily available starting materials.

Investigation of the effect of steroidal imidazoheterocycles hormone derivatives on JEG-3 trophoblast cells of choriocarcinoma

This study aimed to examine the biological activities of unique steroid hormone derivatives-steroidal imidazoheterocycles. The activity synthesized steroidal compounds were tested for the viability of JEG-3 trophoblast cells of choriocarcinoma. The results of the MTT cytotoxicity test showed that most of the examined steroidal imidazoheterocycles act proliferatively on the JEG-3 cell line, except (E, F, and J). Antiproliferative activity of these derivates is probably influenced by different substituents at position 17-C atom in the chemical structure of the hormone and by different substituents on the oxygen atom of acetamide group in the hormone molecule. In order to better confirm the antiproliferative activity of these derivatives, it is necessary to performed complex research on a large panel of cancer cell lines and by different assay.

Novel alkylaminoethyl derivatives of androstane 3-oximes as anticancer candidates: synthesis and evaluation of cytotoxic effects

Steroid anticancer drugs are the focus of numerous scientific research efforts. Due to their high cytotoxic effects against tumor cells, some natural or synthetic steroid compounds seem to be promising for the treatment of different classes of cancer. In the present study, fourteen novel O-alkylated oxyimino androst-4-ene derivatives were synthesized from isomerically pure 3E-oximes, using different alkylaminoethyl chlorides. Their in vitro cytotoxic activity was evaluated against eight human cancer cell lines, as well as against normal fetal lung (MRC-5) and human foreskin (BJ) fibroblasts, to test the efficiency and selectivity of the compounds. Most derivatives displayed strong activity against malignant melanoma (G-361), lung adenocarcinoma (A549) and colon adenocarcinoma (HT-29) cell lines. Angiogenesis was assessed in vitro using migration scratch and tube formation assays on HUVEC cells, where partial inhibition of endothelial cell migration was observed for the 17α-(pyridin-2-yl)methyl 2-(morpholin-4-yl)ethyl derivative. Among the compounds that most impaired the growth of lung cancer A549 cells, the (17E)-(pyridin-2-yl)methylidene derivative bearing a 2-(pyrrolidin-1-yl)ethyl substituent induced significant apoptosis in these cells. In combination with low cytotoxicity toward normal MRC-5 cells, this molecule stands out as a good candidate for further anticancer studies. In addition, in vitro investigations against cytochrome P450 enzymes revealed that certain compounds can bind selectively in the active sites of human steroid hydroxylases CYP7, CYP17A1, CYP19A1 or CYP21A2, which could be important for the development of novel activity modulators of these enzymes and identification of possible side effects.

Novel steroid O-alkylated 3-oxyimino derivatives were synthesized and evaluated in vitro for their antitumor properties. The obtained data indicate the potential of these functionalities for the development of new candidates for tumor treatment.

Apoptosis oxidative damage-mediated and antiproliferative effect of selenylated imidazo[1,2-a]pyridines on hepatocellular carcinoma HepG2 cells and in vivo

Imidazo[1,2-a]pyridines (IP) and organoselenium compounds have been widely exploited in medicinal chemistry due to their pharmacological activities. Hepatocellular carcinoma (HCC) has few treatment options, and unfortunately, the prognosis is poor. Thus, the development of novel therapeutic drugs is urgent. The present study aimed at evaluating the antitumor mechanism of selenylated IP against HepG2 cells and in vivo. The selenylated IP named IP-Se-06 (3-((2-methoxyphenyl)selanyl)-7-methyl-2-phenylimidazol[1,2-a]pyridine) showed high cytotoxicity against HepG2 cells (half-maximal inhibitory concentration [IC₅₀ ] = 0.03 µM) and selectivity for this tumor cell line. At nontoxic concentration, IP-Se-06 decreased the protein levels of Bcl-xL and increased the levels of p53, leading to inhibition of cell proliferation and apoptosis. This compound decreased the level of extracellular signal-regulated kinase 1/2 protein and changed the levels of proteins involved in the drive of the cell cycle, tumor growth, and survival (cyclin B1, cyclin-dependent kinase 2). In addition, IP-Se-06 decreased the number of cells in the S phase. In addition, IP-Se-06 led to increased generation of reactive oxygen species, changed antioxidant defenses, and caused DNA fragmentation. Finally, IP-Se-06 significantly inhibited the growth of Ehrlich ascites tumors in mice, increased survival time, and inhibited angiogenesis. Therefore, IP-Se-06 may be an important compound regarding the development of a therapeutic drug for HCC treatment.