N-Arylation of Amino Acid Esters via an I2-Mediated Metal-Free Multicomponent Benzannulation Strategy.

Herein, we present a novel method for the N-arylation of amino acid esters using α-bromoacetaldehyde acetal and acetoacetate via an I2-mediated metal-free benzannulation strategy, which disclosed the first synthetic application of N-arylation of amino acids using nonaromatic building blocks. The synthesized N-arylated amino acid derivatives were found to possess promising selective inhibition against human hepatocellular liver carcinoma cells, human melanoma cells, and human normal liver cells, with an IC50 value as low as 16.79 µg·mL-1.

Novel Steroidal[17,16-d]pyrimidines Derived from Epiandrosterone and Androsterone: Synthesis, Characterization and Configuration-Activity Relationships.

Two series of novel steroidal[17,16-d]pyrimidines derived from natural epiandrosterone and androsterone were designed and synthesized, and these compounds were screened for their potential anticancer activities. The preliminary bioassay indicated that some of these prepared compounds exhibited significantly good cytotoxic activities against human gastric cancer (SGC-7901), lung cancer (A549), and hepatocellular liver carcinoma (HepG2) cell lines compared with 5-fluorouracil (5-FU), epiandrosterone, and androsterone. Especially the respective pairs from epiandrosterone and androsterone showed significantly different inhibitory activities, and the possible configuration-activity relationships have also been summarized and discussed based on kinase assay and molecular docking, which indicated that the inhibition activities of these steroidal[17,16-d]pyrimidines might obviously be affected by the configuration of the hydroxyl group in the part of the steroidal scaffold.

Structural diversity-guided optimization of carbazole derivatives as potential cytotoxic agents.

Carbazole alkaloids, as an important class of natural products, have been widely reported to have extensive biological activities. Based on our previous three-component reaction to construct carbazole scaffolds, we introduced a methylene group to provide a rotatable bond, and designed series of carbazole derivatives with structural diversity including carbazole amide, carbazole hydrazide and carbazole hydrazone. All synthesized carbazole derivatives were evaluated for their in vitro cytotoxic activity against 7901 (gastric adenocarcinoma), A875 (human melanoma) and MARC145 (African green monkey kidney) cell lines. The preliminary results indicated that compound 14a exhibited high inhibitory activities on 7901 and A875 cancer cells with the lowest IC50 of 11.8 ± 1.26 and 9.77 ± 8.32 µM, respectively, which might be the new lead compound for discovery of novel carbazole-type anticancer agents.

Diarylamine-Guided Carboxamide Derivatives: Synthesis, Biological Evaluation, and Potential Mechanism of Action.

Diarylamines are a class of important skeleton widely existing in drugs or natural products. To discover novel diarylamine analogues as potential drugs, two series of diamide and carboxamide derivatives containing diarylamine scaffold were designed, synthesized and evaluated for their potential cytotoxic activities. The bioassay results indicated that some of the obtained compounds (C5, C6, C7, C11) exhibited good cytotoxic effect on cancer cell lines (SGC-7901, A875, HepG2), especially, compound C11 present significantly selective proliferation inhibition activity on cancer and normal cell lines (MARC145). In addition, the possible apoptosis induction for highly potential molecules was investigated, which present compound C11 could be used as novel lead compound for discovery of promising anticancer agents.

Design, Synthesis, and Cytotoxic Activity of Novel Natural Arylsulfonamide-Inspired Molecules.

Primary arylsulfonamide functional groups feature prominently in diverse pharmaceuticals. However, natural arylsulfonamides are relatively infrequent. In this work, two novel arylsulfonamide natural products were first synthesized, and then a series of novel molecules derived from natural arylsulfonamides were designed and synthesized, and their in vitro cytotoxic activities against A875, HepG2, and MARC145 cell lines were systematically evaluated. The results indicate that some of these arylsulfonamide derivatives exhibit significantly good cytotoxic activity against the tested cell lines compared with the control 5-fluorouracil (5-FU), such as compounds 10l, 10p, 10q, and 10r. In particular, the potential molecule 10q, containing a carbazole moiety, exhibited the highest inhibitory activity against all tested cell lines, with IC50 values of 4.19 ± 0.78, 3.55 ± 0.63, and 2.95 ± 0.78 µg/mL, respectively. This will offer the potential to discover novel drug-like compounds from the sparsely populated area of natural products that can lead to effective anticancer agents.

Identification of Carbazole Alkaloid Derivatives with Acylhydrazone as Novel Anti-TMV Agents with the Guidance of a Digital Fluorescence Visual Screening.

Difficulty in preventing crops from plant viruses urges to discover novel efficient antiviral chemicals, which is sped up by precise screening methods. Fluorescence-based methods have recently been applied as innovative and rapid tools for visually monitoring the replication of viruses and screening of antivirals, whereas the quantification of fluorescence signals mainly depends on manually calculating the fluorescent spots, which is time-consuming and imprecise. In the present work, the fluorescence spots were automatically identified, and the fluorescence area was directly quantified by a program developed in our group, which avoided subjective errors from the operators. We further employed this digital and visual screening assay to identify antivirals using the tobacco mosaic virus-green fluorescence protein (TMV-GFP) construct, in which the expression of GFP intuitively reflected the efficacy of antivirals. The accuracy of this assay was validated by quantifying the activities of the commercial antiviral inhibitors ribavirin and ningnanmycin and then was applied to evaluate the subtle activity differences of a series of newly synthesized carbazole and ß-carboline alkaloid derivatives. Among them, compounds 5 (76%) and 11 (63%) exhibited anti-TMV activities comparable to that of ningnanmycin (65%) at 50 µM, and they delayed the multiplication of TMV in the early stage of infection without phytotoxicity. Taken together, these findings demonstrated that the digital and visual TMV-GFP screening method was competent to test the antiviral activities of compounds with subtle modifications and facilitated the discovery of novel antivirals.

Selective and effective anticancer agents: Synthesis, biological evaluation and structure-activity relationships of novel carbazole derivatives.

Carbazole alkaloids is an important class of natural products with diverse biological functions. So, the aim of this article is to explore new chemical entities containing carbazole scaffold as potential novel cytotoxic agents based on our developed three-component indole-to-carbazole reaction. Two series of carbazole derivatives were designed and synthesized, and their in vitro cytotoxic activities against three cell lines (A875, HepG2, and MARC145) were evaluated. The results indicated that some of these carbazole derivatives exhibited significantly good cytotoxic activities against tested cell lines compared with the control 5-fluorouracil (5-FU). Especially, carbazole acylhydrazone compounds 7g and 7p displayed high inhibitory activity on cancer cells, but almost no activity on normal cells. Further analysis of induced apoptosis for potential compounds indicated that the potential antitumor agents induced cell death in A875 cells at least partly (initially) by apoptosis, which might be used as promising lead scaffold for discovery of novel carbazole-type cytotoxic agents.

Marine Alkaloid Pityriacitrin and Its Analogues: Discovery, Structures, Synthetic Methods and Biological Properties.

Pityriacitrin is a natural marine alkaloid with a typical ß-carboline scaffold, and which has been demonstrated to exhibit diverse biological functions. The special structural features for pityriacitrin lead to the increasing research interest and the emergence of versatile derivatives, and many pityriacitrin analogues have been isolated or synthesized over the past decades. The structural diversity and evolved biological activity of these natural alkaloids can offer opportunities for the development of highly potential novel drugs with a new mechanism of action, and therefore, the aim of this brief review is to describe the discovery, synthesis, and biological properties of natural pityriacitrin and its derivatives, as well as the isolation source.

Synthesis and bioevaluation of novel steroidal isatin conjugates derived from epiandrosterone/androsterone.

Steroids are classes of natural products widely distributed in nature, which have been demonstrated to exhibit broad biological functions, and have also attracted increasing interest from bioorganic and pharmaceutical researches. In order to develop novel chemical entities as potential cytotoxic agents, a series of steroidal isatin conjugations derived from epiandrosterone and androsterone were efficiently prepared and characterized, and all these obtained compounds were screened for their potential cytotoxic activities. The preliminary bioassay indicated that most of the newly synthesized compounds exhibited good cytotoxic activities against human gastric cancer (SGC-7901), melanoma (A875), and hepatocellular liver carcinoma (HepG2) cell lines compared with 5-fluorouracil (5-FU), which might be considered as promising scaffold for further development of potential anticancer agents.

An efficient synthesis and bioactivity evaluation of oxazole-containing natural hinduchelins A-D and their derivatives.

Oxazoles are an important class of biologically active metabolites from nature, and exhibit broad biological activities as the lead for drug discovery. Hinduchelins are a class of unusual natural products with an oxazole unit, isolated from Streptoalloteichus hindustanus, and with a potential iron-chelating ability. These compounds are the first identified naturally occurring unusual oxazole derivatives to possess a catechol unit. However, some of these compounds are not abundant in nature, and thus, the efficient syntheses of these compounds are advantageous in exploring their potential applications. This paper reports the efficient synthesis and bio-evaluation of hinduchelins A-D and their derivatives with convenient procedures and high yields.

Synthesis and biological evaluation of marine alkaloid-oriented ß-carboline analogues.

Pityriacitrin is a marine alkaloid with typical ß-carboline scaffold, and which has been proven to exhibit diverse biological functions. During the course of our research for highly active compounds from natural products, the pityriacitrin have also been isolated and identified from a Chinese Burkholderia sp. NBF227. So, in order to explore the potential functional molecules, a series of ß-carboline analogues derived from pityriacitrin were designed and synthesized, and their in vitro cytotoxic activities against SGC-7901, A875, HepG2, and MARC145 cell lines were evaluated. The results demonstrated that some of these ß-carboline derivatives exhibited moderate to good cytotoxic activities, especially, compound 9o with a special sulfonyl group presented the highest inhibitory activities against all tested cell lines with the IC50 values of 6.82 ±â€¯0.98, 8.43 ±â€¯1.93, 7.69 ±â€¯2.17, 7.19 ±â€¯1.43 µM, respectively, which might be used as lead compound for discovery of novel cytotoxic agents.

Recent Progress of Novel Steroid Derivatives and Their Potential Biological Properties.

Steroid and its derivatives have been proved to have important and diverse biological functions, which present the wide spectrum of biological activities such as antitumor, antiviral, antibacterial, antimicrobial, antifungal, antioxidant, insecticidal, aromatase inhibitors, 5α-reductase inhibitors and neuromuscular blocking agents etc. Versatile features of steroid-derived compounds have emerged, so the aim of the present paper is to review the recent advances of steroid-based derivatives mainly focused on their structures and biological applications, which can be employed for further development to discover potential drug candidates.

Nicotinamide-based diamides derivatives as potential cytotoxic agents: synthesis and biological evaluation.

A series of diamides derivatives containing nicotinamide unit were designed, synthesized and evaluated for their potential cytotoxic activities against human cancer cell lines. All the synthesized compounds were characterized using spectroscopic methods mainly including 1H NMR, 13C NMR and MS. The bio-evaluation results indicated that some of the obtained compounds (such as 4d, 4h, 4i) exhibited good to moderate cytotoxic effects on lung cancer cell lines (NCI-H460, A549, and NCI-H1975), especially, compound 4d exhibited the highly potential inhibitory activities against NCI-H460 cell line with the IC50 values of 4.07 ± 1.30 µg/mL, which might be developed as novel lead compounds for potential cytotoxic agents.

Steroidal[17,16-d]pyrimidines derived from dehydroepiandrosterone: A convenient synthesis, antiproliferation activity, structure-activity relationships, and role of heterocyclic moiety.

A series of steroidal[17,16-d]pyrimidines derived from dehydroepiandrosterone were designed and prepared by a convenient heterocyclization reaction. The in vitro anticancer activities for these obtained compounds were evaluated against human cancer cell lines (HepG2, Huh-7, and SGC-7901), which demonstrated that some of these heterocyclic pyrimidine derivatives exhibited significantly good cytotoxic activities against all tested cell lines compared with 5-fluorouracil (5-FU), especially, compound 3b exhibited high potential growth inhibitory activities against all tested cell lines with the IC50 values of 5.41 ± 1.34, 5.65 ± 1.02 and 10.64 ± 1.49 µM, respectively, which might be used as promising lead scaffold for discovery of novel anticancer agents.

Acylhydrazone derivatives as potential anticancer agents: Synthesis, bio-evaluation and mechanism of action.

A series of novel acylhydrazone derivatives were designed, synthesized and evaluated for their potential cytotoxic effects against human cancer cell lines. The preliminary results indicated that some of the obtained compounds (such as 8b, 13c) exhibited good to moderate cytotoxic activities against human HepG2, Huh-7, and BCG-823 cell lines. Especially, compounds 8c and 8e presented obviously selective cytotoxic activities against Huh-7 in vitro (8c, IC50=7.74±2.18µg/mL; 8e, IC50=4.46±1.05µg/mL) compared to 5-FU (IC50=10.41±3.41µg/mL). The highly potential compounds to induce apoptosis in HepG2 cells were analyzed by flow cytometry, and the apoptotic effects of compounds 8b and 13c were further evaluated using Annexin V-FITC/propidium iodide dual staining assay.

Discovery of novel isatin-dehydroepiandrosterone conjugates as potential anticancer agents.

A series of isatin-dehydroepiandrosterone hybrids were synthesised via a convenient condensation procedure, and which were evaluated for their potential anticancer activities. The preliminary assays indicated that some of the newly obtained compounds exhibited good antitumor activities against human hepatocellular liver carcinoma (HepG2), heptoma (Huh-7), melanoma (A875) and 5-fluorouracil-resistant human hepatocellular carcinoma (BEL-7402/5-FU) cell lines compared with 5-fluorouracil (5-FU), which might be considered as promising lead scaffold for further design and synthesis of highly potential anticancer agents.

Multisubstituted indole-acrylonitrile hybrids as potential cytotoxic agents.

A series of multisubstituted indole-acrylonitrile hybrids were designed, synthesized and evaluated for their potential cytotoxic activities. The bio-evaluation results indicated that some of the target compounds (such as 3a, 3f, 3k, 3n) exhibited good to moderate cytotoxic effect on HepG2, BCG-823, BEL-7402, and HL-7702 cell lines. Especially, the compounds 3a and 3k also exhibited high cytotoxic activities (3a, 19.38±3.38 µM; 3k, 15.43±3.54 µM) against the BEL-7402 cell line resistant to Taxol (>25µM) and 5-FU (>500 µM), which might be developed as novel lead scaffold for potential anticancer agents.

Synthesis of novel steroid derivatives derived from dehydroepiandrosterone as potential anticancer agents.

A series of dehydroepiandrosterone derivatives containing dihydrazone unit was synthesized via a convenient condensation procedure, and which were evaluated for their potential anticancer activities. The preliminary assays indicated that some of the newly synthesized compounds exhibited good antitumor activities against human hepatocellular liver carcinoma (HepG2), heptoma (Huh-7), gastric cancer (BGC-823) and breast adenocarcinoma (MCF-7) cell lines compared with 5-fluorouracil (5-FU), which might be considered as promising lead scaffold for further design and synthesis of potential anticancer agents.

Heterocycle-functional gramine analogues: solvent- and catalyst-free synthesis and their inhibition activities against cell proliferation.

A series of novel gramine analogues were designed and synthesized via a convenient three-component reaction, and which were evaluated for their inhibition activities against cell proliferation. Their structures were confirmed by satisfactory spectra analyses mainly including (1)H NMR, and ESI-MS analyses. The preliminary assays indicated that some of the newly synthesized compounds displayed significantly good inhibition activities against human lung cancer (NCI-H460), hepatocellular liver carcinoma (HepG2), gastric cancer (SGC-7901 and BGC-823) cell lines compared with the control 5-Fluorouracil (5-FU), which might be developed as novel lead scaffold for potential anticancer agents.

Anthranilic acid-based diamides derivatives incorporating aryl-isoxazoline pharmacophore as potential anticancer agents: design, synthesis and biological evaluation.

A series of novel anthranilic diamides derivatives containing aryl-isoxazoline moiety were designed and synthesized as a part of our ongoing search for potential anticancer agents. Their structures were confirmed by (1)H NMR, (13)C NMR and ESI-MS analyses. The preliminary assays showed that some of the compounds displayed moderate to good antitumor activities against human lung cancer (NCI-H460), hepatocellular liver carcinoma (HepG2), gastric cancer (SGC-7901 and BGC-823) and breast epithelial adenocarcinoma (MCF-7) cell lines at µM level, which might be developed as novel lead scaffold for potential anticancer agents.