New N-alkylindole-substituted 2-(pyrid-3-yl)-acrylonitriles with putative kinase inhibitory activity and their (p-cymene)Ru(II) piano-stool complexes were prepared and tested for their antiproliferative efficacy in various cancer models. Some of the indole-based derivatives inhibited tumor cell proliferation at (sub-)micromolar concentrations with IC50 values below those of the clinically relevant multikinase inhibitors gefitinib and sorafenib, which served as positive controls. A focus was set on the investigation of drug mechanisms in HCT-116 p53-knockout colon cancer cells in order to evaluate the dependence of the test compounds on p53. Colony formation assays as well as experiments with tumor spheroids confirmed the excellent antineoplastic efficacy of the new derivatives. Their mode of action included an induction of apoptotic caspase-3/7 activity and ROS formation, as well as anti-angiogenic properties. Docking calculations with EGFR and VEGFR-2 identified the two 3-aryl-2-(pyrid-3-yl)acrylonitrile derivatives 2a and 2b as potential kinase inhibitors with a preferential activity against the VEGFR-2 tyrosine kinase. Forthcoming studies will further unveil the underlying mode of action of the promising new derivatives as well as their suitability as an urgently needed novel approach in cancer treatment. 相似文献
Indole and indoline derivatives were selectively and temperature dependently synthesized via the intramolecular cross‐coupling reaction between the amino and aromatic bromine functionalities of 2‐bromophenethylamine derivatives in the presence of 10% palladium on carbon (Pd/C), 1,1′‐bis(diphenylphosphino)ferrocene (DPPF), and sodium tert‐butoxide (NaO‐t‐Bu) in mesitylene at 140 and 200 °C, respectively. The neutralization using acetic acid after formation of the indoline derivatives effectively promoted their aromatization, and the corresponding indole derivatives were obtained at 140 °C. Furthermore, various aryl groups were also introduced to the N‐1 position of the indole, pyrrole, and carbazole rings by their direct intramolecular arylation with aryl halides and a one‐pot protocol for N‐arylindole synthesis from 2‐bromophenethylamine was developed.
The use of clean and renewable light sources is increasingly common in organic synthesis due to its safety, practicality and economy. Recently, photoredox catalysis has shown great application values in organic transformations because of its advantages of environmentally friendly and abundant resources. Indoles and their derivatives (indolines, oxindoles and isatins) are the core skeletons of some important organic compounds and widely‐present in various natural products and pharmaceuticals with different biological activities. Therefore, the research on the synthesis and modification of indoles is particularly important for chemists and pharmacologists. This review summarizes the effects of photocatalysis on indole synthesis and modification in recent decades. These transformations are accomplished by using metal photocatalysts (i. e., Ir, Ru, Ni, Cu, Fe, Au, Rh, TiO2, etc.) or non‐metallic photocatalysts (i. e., Rose Bengal, Eosin Y, quinones, naphthols, N‐heterocyclic carbenes, carbazoles, pyrylium salts, etc.), or without the need of photocatalysts. The detailed mechanisms of these photo‐catalyzed/promoted organic reactions are also highlighted deeply. And we hope this review will be helpful to researchers interested in this promising field of photocatalyzed transformations.
A highly effective silver(I)‐mediated C H amination of 2‐alkenylanilines has been developed to afford a diverse range of substituted indoles. High functional group tolerance, broad substrate scope, simple/fast/high‐yielding reaction, and recovery/reuse of the inexpensive silver oxidant are noteworthy. Furthermore, an uncommon migratory process of β‐monosubstituted 2‐alkenylanilines with solvent‐dependence was demonstrated.
Di‐ and trisusbstituted indoles 2 have been prepared by reaction of pyrroles 1 with alkenes via iodonium‐induced benzannulation reaction. Enamines and enol ethers are also useful partners in that cyclisation process. This regioselective transformation can be easily adapted to prepare related benzofuran and benzothiophene skeletons. 相似文献
Lanosterol 14α‐demethylase (CYP51) is an important target for antifungal drugs. An improved three‐dimensional model of CYP51 from Candida albicans (CACYP51) was constructed by ligand‐supported homology modeling and molecular dynamics simulations. The accuracy of the constructed model was evaluated by its performance in a small‐scale virtual screen. The results show that known CYP51 inhibitors were efficiently discriminated by the model, and it performed better than our previous CACYP51 model. The active site of CACYP51 was characterized by multiple copy simultaneous search (MCSS) calculations. On the basis of the MCSS results, a series of novel azoles were designed and synthesized, and they showed good in vitro antifungal activity with a broad spectrum. The MIC80 value of four of these compounds against C. albicans is 0.001 μg mL?1, indicating that they are promising leads for the discovery of novel antifungal agents.相似文献
A rhodium(III)‐catalyzed direct ortho C H bond olefination of arenes, including but not limited to benzamides, arylpyridines and indoles, with a variety of unactivated aliphatic olefins has been developed. In the presence of catalytic amounts of dichloro(pentamethylcyclopentadienyl)rhodium(III) dimer {[Cp*RhCl2]2}, copper(II) acetate monohydrate [Cu(OAc)2⋅H2O] and silver hexafluoroantimonate(V) (AgSbF6), the coupling reaction occurred efficiently to afford the ortho‐olefinated linear products in good to excellent yields with high regio‐ and stereoselectivities, and a range of functional groups in both coupling partners is compatible with the reaction conditions. This protocol relies on the use of directing groups, and the addition of AgSbF6 as additive is crucial for the catalysis. This new method expands the scope of rhodium(III)‐catalyzed direct C H bond olefination of arenes, and provides a rapid access to useful linear arylation products of unactivated olefins.
In this paper, a simple and efficient protocol for the chemoselective sulfonation of indoles using aryl sulfonyl chlorides in the presence of CuI is reported. The reaction proceeds under mild conditions and is applicable to indoles bearing a selection of functional groups without NH protection. 相似文献
An efficient strategy for the synthesis of structurally diverse homotryptamines and allyl amines via a Rh(II)‐catalyzed tandem reaction of 1,2,3‐triazolyl esters with either indoles or 1,3,5‐trimethoxybenzene has been developed. The reaction proceeds via Rh(II)‐catalyzed intramolecular rearrangement of triazoles into 1‐azadienes followed by regioselective nucleophilic addition. The efficiency of the current protocol was illustrated by broad substrate scope, gram scale synthesis and further functionalization of homotryptamines into other biologically relevant heterocycles.
The first example of a nickel‐catalyzed C–H trifluoromethylation of electron‐rich heteroarenes, including imidazopyridines, indoles and thiophenes, has been developed with the commercially available and relatively inexpensive industrial raw material iodotrifluoromethane (CF3I) as the trifluoromethylating reagent. The synthetic potential of this method is demonstrated by its successful application to the direct trifluoromethylation of the biologically active molecules melatonin and zolmitriptan.
We report a palladium‐catalyzed C‐2 allylation of indoles and subsequent cyclization of the allylated indoles. The electronic effects of chloro and ester groups that can be readily installed at the C‐3 position of indoles facilitated a highly efficient C–H allylation at the C‐2 position. The resulting 2‐allyl‐3‐chloroindoles were found to be suitable substrates for benzannulation reactions with alkynes and norbornadiene as an acetylene synthon. This approach, utilizing readily available indoles, allyl acetates, and norbornadiene, allows a rapid access to complex carbazoles.
A method to prepare 3‐substituted‐2‐formylindole derivatives from N‐Boc‐ortho‐aminoaryl ketones and ethoxyacetylene through a cascade of reactions in a single operation that included a nucleophile‐triggered 5‐exo‐dig cyclization and an acid‐mediated 1,3‐allyl alcohol isomerization (1,3‐AAI) is described. A variety of aryl, vinyl and alkynyl groups can be introduced at C‐3 of indole‐2‐carboxaldehyde while having a high functional group compatibility. The 3‐alkynyl adducts, which are highly valuable substrates for diversity‐oriented synthesis, can be further transformed to useful carboline and carbazole derivatives through novel pathways.
Product selectivity control for the synthesis of imidoylindoles and 4‐alkylidenedihydroquinazolines from N‐imidoyl‐o‐alkynylanilines via silver triflate‐catalyzed cycloisomerization or tetrabutylammonium fluoride‐promoted cyclization is described. The product selectivity depends mainly on the catalyst/promoter used, and on the substituents on the alkyne and amidine functions of the substrates.
Some readily available Boc‐protected 2‐(3‐methoxy‐1‐propynyl)anilines and nitrones in platinum‐catalyzed reactions deliver [1,2]oxazino[5,4‐b]indoles. Twelve examples with yields of 41–95% are reported. Different substituents like nitro, trifluoromethyl, fluoro, bromo, and ester groups are tolerated. With regard to the mechanism, this reaction probably combines an initial intramolecular cyclization/elimination to vinylcarbenoid species and a subsequent stepwise intermolecular [3+3] cycloaddition with the nitrones. 相似文献
Addition of prochiral cyclic 1,3‐diketones to Michael acceptors applying bifunctional Cinchona‐derived squaramides resulted in chiral adducts with stereoselectivities of up to 99% ee and allowed for desymmetrization of the nucleophile. These labile hemiacetal intermediates were transformed to new 1,4‐dihydropyridines with high diastereoselectivities and no erosion of optical purity. Their further oxidation to pyridine followed by Fisher indolization provided chiral pyridine‐indoles.
A novel multicomponent cascade process is reported, based on the sequential combination between an initial nucleophilic attack step to an imine moiety and a palladium‐catalyzed oxidative heterocyclization‐alkoxycarbonylation process. By this new process, five simple molecules [2‐alkynylaniline imines, alcohol (ROH), carbon monoxide (CO), alcohol (ROH), and oxygen (O2)] are sequentially activated, selectively leading to high value‐added functionalized indole derivatives in a single operation. 相似文献
