Novel 1,4-benzoxazine and 1,4-benzodioxine inhibitors of angiogenesis.

Esters of 1,4-benzoxazine and 1,4-benzodioxine compounds 1 and 10, which combine thrombin inhibitory and GPIIb/IIIa antagonistic activity in one molecule are shown to inhibit endothelial cell migration and tube formation in vitro and angiogenesis in the chicken chorioallantoic membrane (CAM) assay. The corresponding carboxylic acids 1 (R2 = H) and 11 were devoid of antiangiogenic activity, most probably due to their insufficient entry into the cell. Although thrombin inhibition remains the most probable explanation for their inhibition of angiogenesis, VEGFR2 kinase assay suggest that other targets such as VEGFR2 might be involved

Switchable highly regioselective synthesis of 3,4-dihydroquinoxalin-2(1H)ones from o-phenylenediamines and aroylpyruvates

3-Acylmethylidene-3,4-dihydroquinoxalin-2(1H)-ones are compounds which possess a wide range of physical and pharmaceutical applications. These compounds can be easily prepared by cyclocondensation of o-phenylenediamines and aroylpyruvates. Unsymmetrically substituted o-phenylenediamines can be obtained form regioisomeric mixtures of 3,4-dihydroquinoxalin-2(1H)-ones. It is often quite difficult to get a pure regioisomer and determine its structure without controlling the reaction selectivity and exploitation of complex NMR techniques (HSQC, NOESY, HMBC). This article examines the regioselectivity of the cyclocondensation between six monosubstituted o-phenylenediamines (-OMe, -F, -Cl, -COOH, -CN, -NO2) and the derivatives of p-chlorobenzoylpyruvate (ester or acid) which we studied. Six regioisomeric 3,4-dihydroquinoxalin-2(1H)-one pairs were selectively prepared and characterised. Based on our experiences, a simplified methodology for determining the structure of the regioisomers was proposed. We developed two general and highly selective methodologies starting from the same o-phenylenediamines and activated 4-chlorobenzoylpyruvates (ester or acid) enabling switching of 3,4-dihydroquinoxalin-2(1H)-one regioselectivity in a predictable manner. For comparison, all regioselective cyclocondensations were performed with the same standardized conditions (DMF, rt, 3 days), differing only by the additives p-TsOH or HOBt/DIC (hydroxybenzotriazole/N,N’-diisopropylcarbodiimide). Both selected methods are simple, general and highly regioselective (72–97%). A mechanism for the regioselectivity was also proposed and discussed. This study can be used as a guide when choosing the most optimal reaction conditions for the synthesis of the desired 3,4-dihydroquinoxalin-2(1H)-one regioisomers with the best selectivity. The demonstrated methodologies in this article may also be applied to differently substituted 3,4-dihydroquinoxalin-2(1H)-ones in general, which could expand the synthetic impact of our results

Quinoides and VEGFR2 TKIs influence the fate of hepatocellular carcinoma and its cancer stem cells

Bioactivities of quinoides 1-5 and VEGFR2 TKIs 6-10 in hepatocellular cancer (HCC) and cancer stem cells (HCSCs) were studied. The compounds exhibited IC50 values in mu M concentrations in HCC cells. Quinoide 3 was able to eradicate cancer stem cells, similar to the action of the stem cell inhibitor DAPT. However, the more cytotoxic VEFGR TKIs (IC50: 0.4-3.0 mu M) including sorafenib, which is the only FDA approved drug for the treatment of HCC, enriched the hepatocellular cancer stem cell population by 2-3 fold after treatment. An aggressiveness factor (AF) was proposed to quantify the characteristics of drug candidates for their ability to eradicate the CSC subpopulation. Considering the tumour heterogeneity and marker positive cancer stem cell like subpopulation enrichment upon treatments in patients, this study emphasises the importance of the chemotherapeutic agent choice acting differentially on all the subpopulations including marker-positive CSCs

Selectivity of N(2)-substituted oxotriazinoindole aldose reductase inhibitors is determined by the interaction pattern with Pro301-Arg312 loop of aldehyde reductase

Novel oxotriazinoindoles (OTIs) were recently reported as highly efficient and selective aldose reductase inhibitors. Here, a series of novel N(2)-substituted oxotriazinoindoles was developed with the aim to investigate molecular interactions within the aldose reductase (ALR2) inhibitor binding site. About twice increased inhibition efficacy of the most efficient derivative 14 (N(2)-CH2CH2COOH) compared to the unsubstituted lead OTI was obtained, yet at the expense of selectivity relative to anti-target aldehyde reductase (ALR1). To explain the major drop in selectivity, observed also in other N(2)-substituted derivatives, in silico molecular modeling approach revealed the role of extra interactions with the residues of Arg309, Arg312 and Met302 located in the additional C-terminal loop of ALR1 missing in ALR2, which can prevent or enhance binding in ALR1. These key findings will be used for development of the next generation of selective OTI inhibitors. (Figure presented.)

Ynamide Click chemistry in development of triazole VEGFR2 TK modulators

Structure novelty, chemical stability and synthetic feasibility attracted us to design 1,2,3-triazole compounds as potential inhibitors of VEGFR2 tyrosine kinase. Novel triazoles T1-T7 were proposed by oxazole (AAZ from PDB: 1Y6A)/1,2,3-triazole isosteric replacement, molecular modelling and docking. In order to enable synthesis of T1-T7 we developed a methodology for preparation of ynamide 22. Compound 22 was used for all Click chemistry reactions leading to triazoles T1-T3 and T6-T7. Among the obtained products, T1, T3 and T7 specifically bind VEGFR2 TK and modulate its activity by concentration dependent manner. Moreover predicted binding poses of Ti T7 in VEGFR2 TIC were similar to the one known for the oxazole inhibitor AAZ (PDB: 1Y6A). Unfortunately the VEGFR2 inhibition by triazoles e.g. T3 and Ti is lower than that determined for their oxazole bioisosters T3-ox and AAZ, resp. Different electronic properties of 1,2,3-triazole/oxazole heterocyclic rings were proposed to be the main reason for the diminished affinity of T1-T3, T6 and 17 to an oxazole AAZ inhibitor binding site in VEGFR2 TK (PDB: 1Y6A or 1Y6B). Moreover T1-T3 and 16 were screened on cytotoxic activity against two human hepatocellular carcinoma cell lines. Selective cytotoxic activity of T2 against aggressive Mahlavu cells has been discovered indicating possible affinity of T2 to Mahlavu constitutionally active PI3K/Akt pathway. (C) 2015 Elsevier Masson SAS. All rights reserved