A New Benzo[6,7]oxepino[3,2-b] Pyridine Derivative Induces Apoptosis in Canine Mammary Cancer Cell Lines

CMC is the most frequently diagnosed cancer and one of the leading causes of death in non-spayed female dogs. Exploring novel therapeutic agents is necessary to increase the survival rate of dogs with CMC. MPOBA is a BZOP derivative that has a significant anticancer effect in a human cell line. The main goal of this study was to investigate the anticancer properties of MPOBA against two CMC cell lines (REM134 and CMGT071020) using a 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, a wound healing assay, a transwell migration assay, an Annexin V-FITC apoptosis assay with a flow cytometry analysis, a mRNA expression analysis using quantitative real-time PCR (qRT-PCR), and an immunohistochemistry (IHC). According to the accumulated studies, MPOBA caused significant concentration- and time-dependent reductions in cell proliferation and cell migration and induced apoptosis in both CMC cell lines. In gene expression analysis, nine canine genes, including TP53, BCL-2, BAX, epidermal growth factor receptor (EGFR), snail transcription factor (SNAIL), snail-related zinc-finger transcription factor (SLUG), TWIST, E-cadherin, and N-cadherin, were investigated. The mRNA expression results revealed that MPOBA induced upregulation of TP53 and overexpression of the pro-apoptotic gene BAX, together with an inhibition of BCL-2. Moreover, MPOBA also suppressed the mRNA expression levels of SNAIL, EGFR, and N-cadherin and induced upregulation of E-cadherin, crucial genes related to the epithelial-to-mesenchymal transition (EMT). However, there was no significant difference in the IHC results of the expression patterns of vimentin (VT) and cytokeratin (CK) between MPOBA-treated and control CMC cells. In conclusion, the results of the present study suggested that MPOBA exhibited significant anticancer activity by inducing apoptosis in both CMCs via upregulation of TP53 and BAX and downregulation of BCL-2 relative mRNA expression. MPOBA may prove to be a potential candidate drug to be further investigated as a therapeutic agent for CMC.

A New Benzaldehyde Derivative Exhibits Antiaflatoxigenic Activity against Aspergillus flavus

Aflatoxin B1 (AFB1) is the most potent naturally occurring carcinogen for humans and animals produced by the common fungus Aspergillus flavus (A. flavus). Aflatoxin (AF) contamination in commodities is a global concern related to the safety of food and feed, and it also impacts the agricultural economy. In this study, we investigated the AFB1-inhibiting activity of a new benzaldehyde derivative, 2-[(2-methylpyridin-3-yl)oxy]benzaldehyde (MPOBA), on A. flavus. It was found that MPOBA inhibited the production of AFB1 by A. flavus, with an IC50 value of 0.55 mM. Moreover, the inhibition of conidiation was also observed at the same concentration. The addition of MPOBA resulted in decreased transcript levels of the aflR gene, which encodes a key regulatory protein for the biosynthesis of AF, and also decreased transcript levels of the global regulator genes veA and laeA. These results suggested that MPOBA has an effect on the regulatory mechanism of the development and differentiation of conidia, leading to the inhibition of AFB1 production. In addition, the cytotoxicity study showed that MPOBA had a very low cytotoxic effect on the Madin-Darby canine kidney (MDCK) cell line. Therefore, MPOBA may be a potential compound for developing practically effective agents to control AF contamination.

Protecting-Group-Free Total Synthesis of Anticancer (±)-Melotenine A

Melotenine A, isolated from Melodinus tenuicaudatus, possesses significant anticancer activity against several human cancer cell lines. The synthesis of (±)-melotenine A was achieved without the use of any protecting groups in 11 steps with an overall yield of 6.7%. The key steps of our strategy were a Diels–Alder reaction to construct the tetracyclic framework and ring-closing metathesis to form the seven-membered ring of (±)-melotenine A.

One-pot synthesis of 2-arylindole derivatives under transition-metal-free conditions

A new and simple method to prepare 2-arylindole derivatives under transition-metal-free conditions has been developed. When N-acetyl-2-methyl-3-nitroaniline was treated with 2-fluorobenzaldehydes in the presence of Cs2CO3 in DMF at 60 ⁰C, the desired indoles were typically obtained in moderate to good yields (up to 83%). Other aniline substrates were also employed, but only the Knoevenagel condensation occurred to give the corresponding diarylethenes in moderate to excellent yields.

Asymmetric Formal Synthesis of (–)-Swainsonine from Chiral-Pool Precursors d-Mannose and d-Arabinose

Carbohydrates have played an important role in organic synthesis. Since they contain many stereocenters, they have been widely used as chiral-pool starting materials. Herein, we report the asymmetric formal synthesis of (–)-swainsonine, which exhibits anticancer and immunosuppressive activities and inhibits lysosomal α-mannosidase activity, from d-mannose and d-arabinose. The synthesis utilized Zn-mediated Bernet–Vasella reaction, Horner–Wadsworth–Emmons olefination, and Grubbs olefin metathesis as key reactions.

One-Pot Synthesis of Dibenzo[b,f]oxepines and Total Synthesis of Bauhinoxepin C

In this work, we report a novel and simple one-pot synthesis of substituted dibenzo[b,f]oxepines under transition-metal-free conditions. This cascade process involves nucleophilic aromatic substitution followed by Knoevanagel condensation, as evidenced by the isolated reaction intermediates. We have also achieved the synthesis of anticancer bauhinoxepin C in 7 steps with 5.1% overall yield using this synthetic approach.

Self-assembled glucosamine monolayers as biomimetic receptors for detecting WGA lectin and influenza virus with a quartz crystal microbalance

N-Acetylglucosamine (GlcNAc) is a natural ligand that interacts with the binding sites of wheat germ agglutinin (WGA) lectin. For immobilization, GlcNAc was linked to p-nitrophenol, and the nitro group was reduced and then bound to cysteine via two-step synthesis. Scanning tunneling microscopy studies revealed proper immobilization of the ligand on the gold surface of a quartz crystal microbalance (QCM) via the cysteine S-H bond as well as binding between GlcNAc and WGA. QCM measurements revealed that maximum sensitivity towards WGA can only be achieved when co-immobilizing one part ligand and 5,000 parts cysteine for steric reasons, because it allows binding of a protein monolayer on the surface. Langmuir-type treatment of the binding isotherm suggests two different binding ranges for WGA and the GlcNAc monolayer, because at concentrations of WGA below 1 μm the Gibbs energy for the binding process is one third higher than that at concentrations above this value. The same systems can be transferred to first proof-of-concept measurements with different strains of influenza A virus (H5N3, H5N1, H1N3) because GlcNAc is part of the oligosaccharide ligand responsible for the first binding step. Thus, it constitutes both a suitable tool for rapid analysis and the basis for future theoretical calculations of ligand-virus interactions.

Total Synthesis of (±)-Dragmacidin E: Problems Solved and Lessons Learned

(±)-Dragmacidin E was synthesized in 25 steps from commercially available 7-(benzyloxy)indole. Key transformations in this sponge metabolite's preparation include (a) a Witkop cyclization to establish the bridging indole core, (b) cyclo-dehydrative pyrazinone formation to unite the two indole-bearing components, and (c) late-stage guanidine installation via chemoselective carbonyl activation.

Total synthesis of (±)-dragmacidin E

The bis indole sponge alkaloid dragmacidin E was synthesized in racemic form over 25 steps starting from 7-benzhydroxyindole. Key steps include (a) a Witkop cyclization to facilitate construction of the indole-spanning seven-membered ring and (b) a cyclodehydrative pyrazinone synthesis that unites the two indole-containing sectors.

Dragmacidin E synthesis studies. Preparation of a model heptacyclic core structure

The conversion of a cycloheptannelated indole platform into the heptacyclic core structure of dragmacidin E proceeded over nine steps. Key sequences include a cyclocondensation to form an intermediate dihydropyrazinone ring and the conversion of a cyclic urea into the cyclic guanidine of the target.

Dragmacidin E Synthesis Studies. Preparation of a Model Cycloheptannelated Indole Fragment

[reaction: see text] The conversion of N-2,2-dichloropropionyl indole methyl ester into a tetracyclic cycloheptannelated indole model compound for the synthesis of dragmacidin E was accomplished in 10 steps. Key reactions include a Witkop cyclization to fashion a C-C bond at C(4) of the indole nucleus and a subsequent Dieckmann cyclization to deliver the desired cycloheptanoid ring.

Equilibrium constants between boron trifluoride etherate and carbonyl compounds in chloroform solution

[reaction: see text] Equilibrium constants for boron trifluoride complexation with carbonyl compounds relative to diethyl ether were determined in CDCl(3). With benzaldehyde the equilibrium constant is 0.208. There is a 1.28-fold preference for BF(3) bonding to benzaldehyde-D over benzaldehyde-H. The rho(+) value for complexation with substituted benzaldehydes is -2.0. Equilibrium constants with cyclohexanone and isobutyraldehyde were found to be not very different from those predicted from the heats of addition of BF(3) relative to that for diethyl ether. The heats of addition can be correlated with Taft's beta values and with beta' values.