Publications by authors named "Chunchen Liao"

Background: Urinary tract infection (UTI) associated with poses a serious threat for inpatients. This study aimed to describe the genomic characteristics of causing UTI in a tertiary-care hospital in Beijing, China.

Methods: A total of 20 strains collected from 2020 to 2021 were performed whole-genome sequencing.

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Total syntheses of ent-penicillones A (ent-1) and B (ent-2) from 3,5-dimethylcatechol (3) were accomplished in 10 and 9 synthetic steps, respectively. A carbohydrate-templated asymmetric intramolecular Diels-Alder reaction of a masked o-benzoquinone (MOB) 9 and an aqueous acid-catalyzed intramolecular aldol reaction are the key synthetic steps. In addition, the absolute configurations of the bicyclo[2.

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The first total synthesis of ganglioside DSG-A (1) is achieved via chemoselective glycosylation and a [1 + 1 + 2] synthetic strategy. We have also developed an efficient method that can be handled on large scale (50 g) for the synthesis of the phytosphingosine.

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The first asymmetric total syntheses of sesquiterpene lactones (+)-eudesmadiene-12,6-olide (1) and (+)-frullanolide (2) have been accomplished from 4-bromo-2-methoxyphenol (5) in 12 and 13 synthetic steps, respectively, and the absolute configurations of these two natural products were determined.

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We propose a facile approach toward enhancing the efficiency of fluoride-responsive gels through the positioning of functionalized receptor units, allowing tunable intra- and intermolecular hydrogen bonding, in the gelator molecules. We prepared the new glycolipid-based gelator 2 and its hydroxy and methoxy derivatives 2a and 2b, respectively, to study the effects of three types modes of supramolecular assembly: solely intermolecular hydrogen bonding in 2, solely intramolecular hydrogen bonding in 2b, and both inter- and intramolecular hydrogen bonding in 2a. H NMR spectra confirmed the self-assembly interactions of these glycolipid-based gelators.

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The total synthesis of ganglioside 2, an analogue of the ganglioside Hp-s1 (1) which displays neuritogenic activity toward the rat pheochromocytoma cell line PC-12 cell in the presence of nerve growth factor (NGF) with an effect (34.0%) greater than that of the mammalian ganglioside GM 1 (25.4%), was accomplished by applying a chemoselective-activation glycosylation strategy.

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Utilizing scaffold-hopping drug-design strategy, we sought to identify a backup drug candidate for BPR0L075 (1), an indole-based anticancer agent. For this purpose, 5,6-fused bicyclic heteroaromatic scaffolds were designed and synthesized through shuffling of the nitrogen from the N-1 position or by insertion of one or two nitrogen atoms into the indole core of 1. Among these, 7-azaindole core 12 showed potent in vitro anticancer activity and improved oral bioavailability (F = 35%) compared with 1 (F < 10%).

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HTS hit 7 was modified through hybrid design strategy to introduce a chiral side chain followed by introduction of Michael acceptor group to obtain potent EGFR kinase inhibitors 11 and 19. Both 11 and 19 showed over 3 orders of magnitude enhanced HCC827 antiproliferative activity compared to HTS hit 7 and also inhibited gefitinib-resistant double mutant (DM, T790M/L858R) EGFR kinase at nanomolar concentration. Moreover, treatment with 19 shrinked tumor in nude mice xenograft model.

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A focused library of furanopyrimidine (350 compounds) was rapidly synthesized in parallel reactors and in situ screened for Aurora and epidermal growth factor receptor (EGFR) kinase activity, leading to the identification of some interesting hits. On the basis of structural biology observations, the hit 1a was modified to better fit the back pocket, producing the potent Aurora inhibitor 3 with submicromolar antiproliferative activity in HCT-116 colon cancer cell line. On the basis of docking studies with EGFR hit 1s, introduction of acrylamide Michael acceptor group led to 8, which inhibited both the wild and mutant EGFR kinase and also showed antiproliferative activity in HCC827 lung cancer cell line.

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Highly stereoselective hetero Diels-Alder reactions of masked o-benzoquinones (MOBs) with homochiral nitroso dienophiles are described along with their application in the syntheses of (+)-ent-conduramine F-1, (+)-conduramine E-1, (-)-conduramine A-1, (+)-conduramine A-1 tetraacetate, and (-)-ent-conduramine A-1 tetraacetate.

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An efficient and short entry to polyfunctionalized linear triquinanes from 2-methoxyphenols is described by utilizing the following chemistry. The Diels-Alder reactions of masked o-benzoquinones, derived from 2-methoxyphenols, with cyclopentadiene afford tricyclo[5.2.

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By using a cell-based high throughput screening campaign, a novel angelicin derivative 6a was identified to inhibit influenza A (H1N1) virus induced cytopathic effect in Madin-Darby canine kidney cell culture in low micromolar range. Detailed structure-activity relationship studies of 6a revealed that the angelicin scaffold is essential for activity in pharmacophore B, while meta-substituted phenyl/2-thiophene rings are optimal in pharmacophore A and C. The optimized lead 4-methyl-9-phenyl-8-(thiophene-2-carbonyl)-furo[2,3-h]chromen-2-one (8g, IC(50) = 70 nM) showed 64-fold enhanced activity compared to the high throughput screening (HTS) hit 6a.

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Utilizing medicinal chemistry design strategies such as benzo splitting and ring expansion, we converted PPARalpha/gamma dual agonist 1 to selective PPARgamma agonists 19 and 20. Compounds 19 and 20 were 2- to 4-fold better than rosiglitazone at PPARgamma receptor, with 80- to 100-fold PPARgamma selectivity over PPARalpha receptor. X-ray cocrystal studies in PPARgamma and modeling studies in PPARalpha give molecular insights for the improved PPARgamma potency and selectivity for 19 when compared to 1.

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Inverse-electron-demand Diels-Alder reactions of masked o-benzoquinones 2 with phenyl vinyl sulfide and phenyl vinyl selenide furnished highly functionalized bicyclo[2.2.2]octenone derivatives 3 and 4, respectively, in excellent regio- and stereoselectivities and yields up to 90%.

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A four-step stereocontrolled synthesis of polyfunctionalized cis-decalins is described, involving oxidation of 2-methoxyphenol, intermolecular Diels-Alder reaction, olefination, and Cope rearrangement. Application of this efficient strategy to the total syntheses of (+/-)-eremopetasidione, (+/-)-3 beta-angeloyloxyfuranoeremophilane, and (+/-)-3 beta-methacryloyloxyfuranoeremophilane was accomplished from creosol and ethyl vinyl ketone via a common intermediate 21.

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The intramolecular Diels-Alder reaction of o-quinol allyl ether was accomplished and subsequently applied to the first total syntheses of natural products annuionone B (1) and both the proposed and revised structure of tanarifuranonol, 4 and 17.

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Chemoselective photorearrangements of pyrazino-, quinoxalino-, and benzoquinoxalinobarrelenes were investigated by deuterium-labeling experiment. Photolysis of pyrazinobarrelene 4 and quinoxalinobarrelene 5 with 300 nm region light under either direct or sensitized conditions afforded semibullvalenes 7 and 8, respectively; benzoquinoxalinobarrelene 6 was inert to both reaction conditions. Irradiation of deuterated pyrazinobarrelene 4-d4 and quinoxalinobarrelene 5-d4 afforded deuterated semibullvalenes 7-d4-A-7-d4-F and 8-d4-A-8-d4-F, respectively.

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p-Quinol ethers are valuable synthons in synthetic organic chemistry. MOBs 1a-1i can be converted to p-quinol ethers 2a-2i in a highly efficient manner via 1,3-methoxy migration catalyzed by Lewis acids. The migration was found to be reversible and dependent on the electronic effect of substituent R3 of MOBs.

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The first total syntheses of (+/-)-penicillones A (1) and B (2) have been accomplished from 2-methoxy-4,6-dimethylphenol (7) in 9 and 8 synthetic steps, respectively. Intramolecular Diels-Alder reaction of masked o-benzoquinone 8 and aqueous acid-catalyzed intramolecular aldol reaction are the key steps.

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The levels of diastereoselection attainable by addition of vinylmagnesium bromide to a selection of bicyclo[2.2.2]octenone derivatives 1-6 in the presence of various Lewis acids such as LiBr, CeCl3, TiCl4, ZnBr2, MgBr2, and Et2AlCl have been determined.

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Type 2 diabetes has rapidly reached an epidemic proportion becoming a major threat to global public health. PPAR agonists have emerged as a leading class of oral antidiabetic drugs. We report a structure biology analysis of novel indole-based PPAR agonists to explain the structure-activity relationships and present a critical analysis of reasons for change in selectivity with change in the orientation of the same scaffolds.

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