Facile Synthesis of Pyrrolyl 4-Quinolinone Alkaloid Quinolactacide by 9-AJ-Catalyzed Tandem Acyl Transfer-Cyclization of o-Alkynoylaniline Derivatives.
ABSTRACT: The synthesis of pyrrolyl 4-quinolinone alkaloid, quinolactacide, and its analogues was successfully achieved using 9-azajulolidine (9-AJ)-catalyzed tandem acyl transfer-regioselective cyclization of N,N-diacyl-o-alkynoylaniline derivatives. In addition, this organocatalytic reaction was successfully utilized for the synthesis of a variety of 3-acyl-4-quinolinones in moderate-to-good yields. Mechanistic studies, including a time course nuclear magnetic resonance (NMR) experiment, indicated that the 1,4-addition of 9-AJ to an ynone system can be considered to be the rate-determining step in this quinolinone synthesis.
Project description:A highly efficient solid-phase synthesis of 2-substituted-3-hydroxy-4(1H)-quinolinone-7-carboxamides was developed using anthranilates and bromoketones as the key synthons. Primary amines immobilized to an acid-cleavable BAL linker were acylated with 1-methyl-2-aminoterephtalate. After cleavage of the methyl ester, bromoketones were used to form resin-bound phenacyl esters. Acid-mediated cleavage and subsequent cyclization in solution afforded 3-hydroxy-4(1H)-quinolinones in high purity and yield. Highly efficient solid-phase synthesis (purity>90%, yield>80%, synthetic time=2 days using commercially available synthons) is amenable to high-throughput/combinatorial synthesis to match the high-throughput screening capability.
Project description:The synthesis of fully substituted α-N-pyrrolyl and indolyl ketones via enantioselective palladium-catalyzed allylic alkylation is described. The acyclic ketones are alkylated in high yields with high enantioselectivities through the use of an electron-deficient phosphinooxazoline ligand, furnishing a highly congested and synthetically challenging stereocenter. The obtained alkylation products contain multiple reactive sites poised for additional functionalizations and diversification.
Project description:As a major component of the cytoskeleton, microtubules consist of ??-tubulin heterodimers and have been recognized as attractive targets for cancer chemotherapy. Microtubule-stabilizing agents (MSAs) promote polymerization of tubulin and stabilize the polymer, preventing depolymerization. The molecular mechanisms by which MSAs stabilize microtubules remain elusive. Here we report a 2.05?Å crystal structure of tubulin complexed with taccalonolide AJ, a newly identified taxane-site MSA. Taccalonolide AJ covalently binds to ?-tubulin D226. On AJ binding, the M-loop undergoes a conformational shift to facilitate tubulin polymerization. In this tubulin-AJ complex, the E-site of tubulin is occupied by GTP rather than GDP. Biochemical analyses confirm that AJ inhibits the hydrolysis of the E-site GTP. Thus, we propose that the ?-tubulin E-site is locked into a GTP-preferred status by AJ binding. Our results provide experimental evidence for the connection between MSA binding and tubulin nucleotide state, and will help design new MSAs to overcome taxane resistance.
Project description:These data are related to our previous paper “Synthesis and approbation of new neuroprotective chemicals of pyrrolyl- and indolylazine classes in a cell model of Alzheimer's disease” (Dutysheva et al., 2021), in which we demonstrate neuroprotective abilities of pyrrolyl- and indolylazines in a cell model of Alzheimer's disease. Using a novel procedure of photocatalysis we have synthesized a group of new compounds. The current article presents nuclear magnetic resonance spectra including heteronuclear single quantum coherence spectra of chemicals synthesized by us. The effect of new compounds have on heat shock proteins genes expression in reprogrammed human neurons are presented. We also presented data that verify neuronal phenotype of reprogrammed cells.
Project description:SARS CoV 3CLpro is known to be a promising target for development of therapeutic agents against the severe acute respiratory syndrome (SARS). A quinolinone compound 1 was selected via virtual screening, and it was synthetized and tested for enzymatic inhibition in vitro. Compound 1 showed potent inhibitory activity (IC50=0.44 µmol/L) toward SARS CoV 3CLpro. Further work on a series of quinolinone derivatives resulted in the discovery of the most potent compound 23, inhibiting SARS CoV 3CLpro with an IC50 of 36.86 nmol/L. The structure-activity relationships were also discussed.
Project description:The taccalonolides are microtubule stabilizers that covalently bind tubulin and circumvent clinically relevant forms of resistance to other drugs of this class. Efforts are under way to identify a taccalonolide with optimal properties for clinical development. The structurally similar taccalonolides AF and AJ have comparable microtubule-stabilizing activities in vitro, but taccalonolide AF has excellent in vivo antitumor efficacy when administered systemically, while taccalonolide AJ does not elicit this activity even at maximum tolerated dose. The hypothesis that pharmacokinetic differences underlie the differential efficacies of taccalonolides AF and AJ was tested. The effects of serum on their in vivo potency, metabolism by human liver microsomes and in vivo pharmacokinetic properties were evaluated. Taccalonolides AF and AJ were found to have elimination half-lives of 44 and 8.1 min, respectively. Furthermore, taccalonolide AJ was found to have excellent and highly persistent antitumor efficacy when administered directly to the tumor, suggesting that the lack of antitumor efficacy seen with systemic administration of AJ is likely due to its short half-life in vivo. These results help define why some, but not all, taccalonolides inhibit the growth of tumors at systemically tolerable doses and prompt studies to further improve their pharmacokinetic profile and antitumor efficacy.
Project description:An efficient synthesis of tetrahydrocarboline-type products and polycyclic spiroindolines has been achieved. The transformation proceeds via rhodium(II)-catalyzed intramolecular annulations of indolyl- and pyrrolyl-tethered N-sulfonyl-1,2,3-triazoles. The reaction could be tuned toward either the formal [3 + 2] cycloaddition or the C-H functionalization reaction depending on the electronic and structural features of the substrates, leading to the production of a variety of structurally related heterocyclic compounds.
Project description:Rhabdomyosarcoma (RMS) forms in skeletal muscle and is the most common soft tissue sarcoma in children and adolescents. Current treatment is associated with debilitating side effects and treatment outcomes for patients with metastatic disease are dismal. Recently, a novel binuclear palladacycle, AJ-5, was shown to exert potent cytotoxicity in melanoma and breast cancer and to present with negligible adverse effects in mice. This study investigates the anti-cancer activity of AJ-5 in alveolar and embryonal RMS. IC50 values of ??0.2?µM were determined for AJ-5 and it displayed a favourable selectivity index of >2. Clonogenic and migration assays showed that AJ-5 inhibited the ability of RMS cells to survive and migrate, respectively. Western blotting revealed that AJ-5 induced levels of key DNA damage response proteins (?H2AX, p-ATM and p-Chk2) and the p38/MAPK stress pathway. This correlated with an upregulation of p21 and a G1 cell cycle arrest. Annexin V-FITC/propidium iodide staining revealed that AJ-5 induced apoptosis and necrosis. Apoptosis was confirmed by the detection of cleaved PARP and increased levels and activity of cleaved caspases-3, -7, -8 and -9. Furthermore, AJ-5 reduced autophagic flux as shown by reduced LC3II accumulation in the presence of bafilomycin A1 and a significant reduction in autophagosome flux J. Finally, pharmacokinetic studies in mice show that AJ-5 has a promising half-life and that its volume of distribution is high, its clearance low and its intraperitoneal absorption is good. Together these findings suggest that AJ-5 may be an effective chemotherapeutic with a desirable mechanism of action for treating drug-resistant and advanced sarcomas.
Project description:AJ mouse is susceptible to lung carcinogenesis from urethane treatment and is a good model for human adenocarcinoma. We completed a study using microarray analysis of bronchoalveolar lavage cells from control or urethane treated mice. A unique macrophage expression signature in the lung tumor microenvironment was able to correctly classify the lavage samples. Experiment Overall Design: RNA from bronchoalveolar lavage cells of age matched untreated AJ mice controls (C) or from urethane treated (T) AJ mice was prepared. Datasets were accurately classified using a unique macrophage gene expression signature derived from the tumor microenvironment.
Project description:A series of a new type of Schiff bases 1-7, derived from 2-phenyl-3-amino-4(1H)-quinolinone and R-salicyladehyde derivatives wherein R = 3-hydroxy (1), 3,4-dihydroxy (2), 3-methoxy (3), 3-carboxy (4), 3-allyl (5), 5-chloro (6), and 5-nitro (7), was synthesized and structurally characterized. Each of the molecules 1, 3 and 7 consists of three planar moieties (i.e., a quinolinone and two phenyl rings), which are mutually oriented differently depending on the appropriate substituent R and the extent of non-covalent contacts stabilizing the crystal structures. The compounds were studied for their fluorescence properties, where compound 6 yielded the strongest intensity both in the solid phase and in 100 μM ethanol solution with a quantum yield of φ = 3.6% as compared to quinine sulfate used as a standard. The in vitro cytotoxicity of these compounds was tested against the human osteosarcoma (HOS) and breast adenocarcinoma (MCF7) cell lines, revealing no activity up to the concentration of 50 µM.