Solvent-free and room temperature synthesis of 3-arylquinolines from different anilines and styrene oxide in the presence of Al₂O₃/MeSO₃H

• Hashem Sharghi,
• Mahdi Aberi,
• Mohsen Khataminejad and
• Pezhman Shiri

Beilstein J. Org. Chem. 2017, 13, 1977–1981, doi:10.3762/bjoc.13.193

• anilines with styrene oxide via C–C cleavage is the efficient synthetic route to quinolones [1]. The reaction was performed using FeCl3 as catalyst in 1,4-dioxane as solvent at 110 °C for 12 h. According to the significance of this progress, we have decided to re-optimize it. The mixture of Al2O3 and

Chemical probes for competitive profiling of the quorum sensing signal synthase PqsD of Pseudomonas aeruginosa

• Michaela Prothiwa,
• Dávid Szamosvári,
• Sandra Glasmacher and
• Thomas Böttcher

Beilstein J. Org. Chem. 2016, 12, 2784–2792, doi:10.3762/bjoc.12.277

• for the development of customized PqsD inhibitors as well as a chemical toolbox to investigate the activity and active site specificity of the enzyme. Keywords: activity-based probes; PqsD; protein labelling; Pseudomonas aeruginosa; quinolones; Introduction The emergence of multi-drug resistant

• . This simple signaling strategy thus regulates bacterial behaviour in dependence of population density. One of these quorum sensing systems, the pqs system, uses 2-alkyl-4-quinolones (AQs) as signals of which the Pseudomonas quinolone signal (PQS) and its biosynthetic precursor 2-heptyl-4-quinolone (HHQ

• combination, our probes and their inhibitors represent a valuable toolkit for investigating this important virulence-related enzyme. Quinolone signals of Pseudomonas aeruginosa. A) Structures of HHQ and PQS. B) Proposed mechanism for the synthesis of 2-alkyl-4-quinolones [12][13][14]. Synthesis of

Discovery of an inhibitor of the production of the Pseudomonas aeruginosa virulence factor pyocyanin in wild-type cells

• Bernardas Morkunas,
• Balint Gal,
• Warren R. J. D. Galloway,
• James T. Hodgkinson,
• Brett M. Ibbeson,
• Yaw Sing Tan,
• Martin Welch and
• David R. Spring

Beilstein J. Org. Chem. 2016, 12, 1428–1433, doi:10.3762/bjoc.12.137

• reminiscent of 2-alkyl-4(1H)-quinolones, which are known to have effects upon quorum sensing in P. aeruginosa, including pyocyanin production [8][9][35]. Thus, the cognate receptor of PQS, PqsR, could be a target of 4; however, other targets of 4 cannot as yet be ruled out. Further investigations into the

An intramolecular C–N cross-coupling of β-enaminones: a simple and efficient way to precursors of some alkaloids of Galipea officinalis

• Hana Doušová,
• Radim Horák,
• Zdeňka Růžičková and
• Petr Šimůnek

Beilstein J. Org. Chem. 2015, 11, 884–892, doi:10.3762/bjoc.11.99

• catalytic hydrogenation of the corresponding quinolones 2 (Scheme 2) with yields not greater than 43%. In the present work, we introduce a quite different approach to the exocyclic enaminones 1 based on an intramolecular C–N cross-coupling of enaminones 3 (Scheme 2). Results and Discussion The synthesis of

Aza-Diels–Alder reaction between N-aryl-1-oxo-1H-isoindolium ions and tert-enamides: Steric effects on reaction outcome

• Amitabh Jha,
• Ting-Yi Chou,
• Zainab ALJaroudi,
• Bobby D. Ellis and
• T. Stanley Cameron

Beilstein J. Org. Chem. 2014, 10, 848–857, doi:10.3762/bjoc.10.81

• N-aryl-3-hydroxyisoindolinones with diethyl malonate and subsequent hydrolysis, decarboxylation and Friedel–Crafts acylation sequence also result in the formation of isoindolo[2,1-a]quinolones [16][17]. N-aryl-3-hydroxyisoindolinones with an aptly positioned alkene moiety at the ortho position of

Synthesis and biological activities of the respiratory chain inhibitor aurachin D and new ring versus chain analogues

• Xu-Wen Li,
• Jennifer Herrmann,
• Yi Zang,
• Philippe Grellier,
• Soizic Prado,
• Rolf Müller and
• Bastien Nay

Beilstein J. Org. Chem. 2013, 9, 1551–1558, doi:10.3762/bjoc.9.176

• cyclization. Keywords: antiplasmodial activities; Conrad–Limpach reaction; mitochondrial membrane potential; natural products; quinolones; total synthesis; Introduction The four aurachins A–D (1–4) were first isolated from the myxobacterium Stigmatella aurantiaca strain Sg a15 in 1987 (Figure 1) [1]. This

• (15) and methyl 3-aminobenzoate (16), using the 2-farnesyl(acetoacetate) 8a. Not surprisingly, only the electron-rich anilines 12–14 were reactive enough to furnish the expected 3-farnesyl-4(1H)-quinolones 17–19 in moderate to good yields (Table 1). The electron-poor anilines 15 and 16 were unreactive

• only the total synthesis of aurachin D (4) was accomplished, but also that of analogues with variations in chain length or aromatic cycle. The general strategy involved a key Conrad–Limpach synthesis of quinolones. Additionally, we were able to build the carboheterocyclic core of aurachin H (6) under

Zanthoxoaporphines A–C: Three new larvicidal dibenzo[de,g]quinolin-7-one alkaloids from Zanthoxylum paracanthum (Rutaceae)

• Fidelis N. Samita,
• Louis P. Sandjo,
• Isaiah O. Ndiege,
• Ahmed Hassanali and
• Wilber Lwande

Beilstein J. Org. Chem. 2013, 9, 447–452, doi:10.3762/bjoc.9.47

• , namely isoquinolines represented by benzophenanthridines [8], oxoaporphines [9], aporphines [10] and benzylisoquinoline [11]; and quinolines represented by quinolones [12] and furoquinolines [10]. Others include carbazoles [13], pyrido-indoles [12] and quinazolines [14]. Arylethanamides and amines have

Synthesis of SF₅-containing benzisoxazoles, quinolines, and quinazolines by the Davis reaction of nitro-(pentafluorosulfanyl)benzenes

• Petr Beier and
• Tereza Pastýříková

Beilstein J. Org. Chem. 2013, 9, 411–416, doi:10.3762/bjoc.9.43

• powder in aqueous acetic acid according to the literature procedure (Table 2) [31]. Aminoketones 10 and 11 were investigated as starting substrates in the synthesis of various nitrogen heterocycles by condensation reactions. Several reliable synthetic methods giving quinolones [32][33] or quinazolines

Dipyrazolo[1,5-a:4',3'-c]pyridines – a new heterocyclic system accessed via multicomponent reaction

• Wolfgang Holzer,
• Gytė Vilkauskaitė,
• Eglė Arbačiauskienė and
• Algirdas Šačkus

Beilstein J. Org. Chem. 2012, 8, 2223–2229, doi:10.3762/bjoc.8.251

• of adenosine and, thus, has been incorporated in various compounds impairing protein kinases and ATPases [7][8][9]. Moreover, a large variety of additional fused pyrazoles exhibit interesting biological activities, such as, pyrazolo[1,5-a]quinolones [10], pyrazolo[4,3-c]quinolones [11], pyrazolo[5,1

Flow photochemistry: Old light through new windows

• Jonathan P. Knowles,
• Luke D. Elliott and
• Kevin I. Booker-Milburn

Beilstein J. Org. Chem. 2012, 8, 2025–2052, doi:10.3762/bjoc.8.229

DBFOX- Ph/metal complexes: Evaluation as catalysts for enantioselective fluorination of 3-(2-arylacetyl)-2-thiazolidinones

• Takehisa Ishimaru,
• Norio Shibata,
• Dhande Sudhakar Reddy,
• Takao Horikawa,
• Shuichi Nakamura and
• Takeshi Toru

Beilstein J. Org. Chem. 2008, 4, No. 16, doi:10.3762/bjoc.4.16

• electrophilic fluorination represents an important and straightforward strategy for C-F bond formation at a carbon stereocenter, providing easy access to chiral fluoro-organic compounds [1][2]. Due to the significance of chiral fluoro-organic compounds, such as fluorinated quinolones [3][4] and liquid crystals

The Elbs and Boyland- Sims peroxydisulfate oxidations

• E. J. Behrman

Beilstein J. Org. Chem. 2006, 2, No. 22, doi:10.1186/1860-5397-2-22

• -reaction and so increases the yield of the expected Elbs product, orotic acid 5-sulfate. Quinolones are another interesting case: 4-quinolones give reasonable yields of the expected 3-substitution products whereas 2-quinolones do not. [6] An explanation has been suggested which concerns the stability of

• facts imply a side-reaction in which the phenol serves as a catalyst in a set of reactions which leads to the consumption of peroxydisulfate. A particularly striking case is that of the 2-quinolones where no Elbs product is formed although peroxydisulfate is consumed at a reasonable rate. [6] Para

• poorly characterized. It seems clear that small proportions of starting materials, particularly for such substrates as the 2-quinolones, can undergo extensive oxidation probably involving catalysis by adventitious metal ions. Thus Walling and Buckler [17] reacted phenyl magnesium bromide with oxygen and