Oxidative dehydrogenation of C–C and C–N bonds: A convenient approach to access diverse (dihydro)heteroaromatic compounds

• Santanu Hati,
• Ulrike Holzgrabe and
• Subhabrata Sen

Beilstein J. Org. Chem. 2017, 13, 1670–1692, doi:10.3762/bjoc.13.162

• ]. Recently Xiao et al. [94] has reported an acceptor-free oxidative dehydrogenation with a versatile iridium catalyst (Scheme 35). A variety of tetrahydroquinolines 93 were converted to the aromatic quinoline 94 using the iridium catalyst in 2,2,2-trifluoroethanol (TFE) at higher temperature. As an extension

• et al. utilized a modular catalytic system comprised of C-quinones for the oxidative dehydrogenation of tetrahydroquinolines 104 to an (2,1-c)quinoline 105. This was further transformed to 106, an antiprotozoal agent, and 107, a topoisomerase inhibitor, presently in the phase II clinical trial

The chemistry and biology of mycolactones

• Matthias Gehringer and
• Karl-Heinz Altmann

Beilstein J. Org. Chem. 2017, 13, 1596–1660, doi:10.3762/bjoc.13.159

Continuous-flow processes for the catalytic partial hydrogenation reaction of alkynes

• Carmen Moreno-Marrodan,
• Francesca Liguori and
• Pierluigi Barbaro

Beilstein J. Org. Chem. 2017, 13, 734–754, doi:10.3762/bjoc.13.73

• uptake and use of an excess of amine (quinoline) modifier [12][13], with serious drawbacks in terms of process economy, environmental impact and product separation management. The development of cost-effective, well-defined, efficient and environmentally friendly catalytic systems for the partial

• other personal care products [164]. The highest selectivity so far reported in batch conditions was observed using dendron-stabilized PdNP catalysts with quinoline additives (97% ene, 98% Z) [165]. The only example described under continuous flow used the Pd@monobor catalysts to achieve a 96% conversion

N-Propargylamines: versatile building blocks in the construction of thiazole cores

• S. Arshadi,
• E. Vessally,
• L. Edjlali,
• R. Hosseinzadeh-Khanmiri and
• E. Ghorbani-Kalhor

Beilstein J. Org. Chem. 2017, 13, 625–638, doi:10.3762/bjoc.13.61

• patterns. It is well known that they can undergo a number of cyclization reactions to produce various N-heterocycles and complex natural products. In this context we recently reviewed their role in the syntheses of pyrrole [65], pyridine [66], quinoline [67], pyrazine [68], 1,4-oxazepane, and 1,4-diazepane

Transition-metal-catalyzed synthesis of phenols and aryl thiols

• Yajun Liu,
• Shasha Liu and
• Yan Xiao

Beilstein J. Org. Chem. 2017, 13, 589–611, doi:10.3762/bjoc.13.58

• -mediated hydroxylation of (2-pyridyl)arenes. Removable pyridine moiety directed hydroxylation of arenes. Removable quinoline moiety directed hydroxylation of arenes. CuCl2 catalyzed hydroxylation of benzimidazoles and benzoxazoles. Disulfide-directed C–H hydroxylation. Pd(OAc)2-catalyzed hydroxylation of

Pd- and Cu-catalyzed approaches in the syntheses of new cholane aminoanthraquinone pincer-like ligands

• Nikolay V. Lukashev,
• Gennadii A. Grabovyi,
• Dmitry A. Erzunov,
• Alexey V. Kazantsev,
• Gennadij V. Latyshev,
• Alexei D. Averin and
• Irina P. Beletskaya.

Beilstein J. Org. Chem. 2017, 13, 564–570, doi:10.3762/bjoc.13.55

• (6a) is readily aminated by phthalimide using classical Ullmann conditions (15% Cu powder, quinoline, 200 °C in PhNO2) [41]. However, the reaction of 3c with 6a using the same conditions, as well as the addition of stronger bases (DABCO, DIPEA, DBU) afforded extremely low yields (7–12%) of aminated

Synthesis of 1-indanones with a broad range of biological activity

• Marika Turek,
• Dorota Szczęsna,
• Marek Koprowski and
• Piotr Bałczewski

Beilstein J. Org. Chem. 2017, 13, 451–494, doi:10.3762/bjoc.13.48

• heating in quinoline (Scheme 71). Gacs-Baitz et al. have applied the Diels–Alder reaction between 1,2-dihydro-4-vinylnaphthalene (259) and 2-bromo-4-acetoxy-2-cyclopenten-1-one (260) to synthesize 1-indanone derivative 261 (Scheme 72) [101]. Koreeda and Woski have synthesized the cyclopenta[α]phenanthrene

A novel method for heterocyclic amide–thioamide transformations

• Walid Fathalla,
• Ibrahim A. I. Ali and
• Pavel Pazdera

Beilstein J. Org. Chem. 2017, 13, 174–181, doi:10.3762/bjoc.13.20

• heating isatine with malonic acid followed by esterification of the produced quinoline carboxylic acid with methanol in the presence of sulfuric acid at 80 °C for 6 h. 4-Arylphthalazin-1(2H)-ones A7 and A8 [24][25] were prepared by Friedel–Crafts acylation reaction of N-aminophthalimide with either

• cyclohexylammonium salt (2). The two-step thiation of quinazolin-4-one A1–6 and phthalazin-1-ones A7 and A8. Thiation of quinoline A9 and quinoxalinone A10–13. Rational mechanism of the reaction of 4-chloro-2-phenylquinazoline (B2) to 2-phenylquinazolin-4(3H)-thione. Synthesis of quinazolin-4-thionesa. Synthesis of

Direct arylation catalysis with chloro[8-(dimesitylboryl)quinoline-κN]copper(I)

• Sem Raj Tamang and
• James D. Hoefelmeyer

Beilstein J. Org. Chem. 2016, 12, 2757–2762, doi:10.3762/bjoc.12.272

• )quinoline-κN]copper(I) (2, Scheme 1), and investigate its performance as a catalyst for direct arylation reactions. We note that compound 2 consists of the ambiphilic ligand 1 coordinated to Cu(I) via nitrogen atom coordination and an η3-BCC interaction [52]. Herein we report the use of the preformed

A new paradigm for designing ring construction strategies for green organic synthesis: implications for the discovery of multicomponent reactions to build molecules containing a single ring

• John Andraos

Beilstein J. Org. Chem. 2016, 12, 2420–2442, doi:10.3762/bjoc.12.236

• dihydropyridine, hydantoin, imidazole, indole, isoquinoline, isoxazole, oxazole, 4H-pyran, pyrazine, pyridazine, pyridine, pyridinone, pyrimidine, pyrimidone, pyrrole, 3H-quinazolin-4-one, quinoline, 1H-quinolin-4-one, and thiophene. For heterocycles that are composed of a fused aromatic ring, such as

Practical synthetic strategies towards lipophilic 6-iodotetrahydroquinolines and -dihydroquinolines

• David R. Chisholm,
• Garr-Layy Zhou,
• Ehmke Pohl,
• Roy Valentine and
• Andrew Whiting

Beilstein J. Org. Chem. 2016, 12, 1851–1862, doi:10.3762/bjoc.12.174

• corresponding 1,4-DHQ of scaffold 1 has not been synthesised to our knowledge. Similar DHQs are typically prepared by methods such as ring-closing metathesis, or by controlled Birch-type reductions of the corresponding quinoline [10][11][12]. Very few instances of iodine-containing THQs or DHQs exist in the

• (ca. 5%) of 1,4-DHQ 22 in addition to 21. Ab initio simulation of 22 (Figure 2) indicated that the enamine functionality causes a flattening of the dihydroquinoline ring to give a more planar, quinoline-like structure. We were intrigued by the result of these stereoelectronic and conformational

• free of charge from The Cambridge Crystallographic Data Centre via http://www.ccdc.cam.ac.uk/getstructures. Tetrahydroquinoline (THQ) and dihydroquinoline (DHQ) scaffolds to be synthesised. Simulated structure of 22 indicates a flattened quinoline-like structure. Hartree–Fock calculations (3-21G*) were

Mutagenic activity of quaternary ammonium salt derivatives of carbohydrates

• Barbara Dmochowska,
• Karol Sikora,
• Anna Woziwodzka,
• Jacek Piosik and
• Beata Podgórska

Beilstein J. Org. Chem. 2016, 12, 1434–1439, doi:10.3762/bjoc.12.138

• -methylimidazo[4,5-f]quinoline [IQ], 50 nmol/plate). Results are reported as percentage number of revertants observed for the positive control (C2). Bars indicate mean values from three plates ± standard deviation. Reagents and conditions; I: HO(CH2)6Br, BF3·Et2O/CH2Cl2, 1 h 0 °C → 3 h, rt, ([32] compound 2 36

Molecular weight control in organochromium olefin polymerization catalysis by hemilabile ligand–metal interactions

• Stefan Mark,
• Hubert Wadepohl and
• Markus Enders

Beilstein J. Org. Chem. 2016, 12, 1372–1379, doi:10.3762/bjoc.12.131

• Stefan Mark Hubert Wadepohl Markus Enders Anorganisch-Chemisches Institut, Heidelberg University, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany 10.3762/bjoc.12.131 Abstract A series of Cr(III) complexes based on quinoline-cyclopentadienyl ligands with additional hemilabile side arms were

Multicomponent reactions: A simple and efficient route to heterocyclic phosphonates

• Mohammad Haji

Beilstein J. Org. Chem. 2016, 12, 1269–1301, doi:10.3762/bjoc.12.121

• the three-component reaction of 4-chlorobenzaldehyde (238), aminomethylphosphonate 239 and ynones 240 in 57% yield (Scheme 49). 7 Reissert-type multicomponent reactions The traditional Reissert reaction is a one-pot treatment of quinoline (242) with acid chlorides 243 and KCN to afford Reissert

• compound 244 which can be hydrolyzed to give quinoline-2-carboxylic acid (245) (Scheme 50) [87]. This reaction can also be applied to isoquinolines and some pyridines. Additionally, a wide range of activating groups such as chloroformates, acetylenic esters, R3SiOTf, Tf2O and various nucleophiles can be

• ) [88]. Further, 1-acyl-1,2-dihydroquinoline-2-phosphonates 251 and 2-acyl-1,2-dihydroisoquinoline-1-phosphonates 252 have been prepared via the one-pot reaction of quinoline (242) or isoquinolines 249 with acyl chlorides 250 and trimethyl phosphite in the presence of NaI in 22–94% yields depending on

Reactions of N,3-diarylpropiolamides with arenes under superelectrophilic activation: synthesis of 4,4-diaryl-3,4-dihydroquinolin-2(1H)-ones and their derivatives

• Larisa Yu. Gurskaya,
• Diana S. Belyanskaya,
• Dmitry S. Ryabukhin,
• Denis I. Nilov,
• Irina A. Boyarskaya and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2016, 12, 950–956, doi:10.3762/bjoc.12.93

• superelectrophilic activation of the N-formyl group by TfOH in the reaction with benzene resulted in the formation of N-(diphenylmethyl)-substituted dihydroquinolinones. Keywords: alkynes; quinolinones; Friedel–Crafts reactions; superacids; superelectrophilic activation; Introduction Quinoline derivatives are a

• very important class of heterocycles, which are used in chemistry, biology, medicine, and materials science. For instance, see a series of recent reviews on anti-malaria drugs containing a quinoline motif in the structure [1][2][3]. The synthesis of quinolines is an important task of organic chemistry

• ][12][13][14], we continued to develop some methods for the syntheses of quinoline derivatives. Previously we showed, just in a few examples, that some 3-aryl-N-(aryl)propiolamides reacted with benzene under the action of Brønsted or Lewis superacids affording 4-aryl-4-phenyl-3,4-dihydroquinolin-2(1H

1H-Imidazol-4(5H)-ones and thiazol-4(5H)-ones as emerging pronucleophiles in asymmetric catalysis

• Antonia Mielgo and
• Claudio Palomo

Beilstein J. Org. Chem. 2016, 12, 918–936, doi:10.3762/bjoc.12.90

• with the phenyl and 2-naphthylthiazolones, respectively (Scheme 12, compound 70 versus 71 and 72 versus 73). On this basis, the authors propose a bifunctional way of action of the catalyst, wherein the pyridine/quinoline nitrogen could coordinate to one of the free N–H hydrogen atoms of the catalyst. α

A robust synthesis of 7,8-didemethyl-8-hydroxy-5-deazariboflavin

• Matthias Bender,
• Henrik Mouritsen and
• Jens Christoffers

Beilstein J. Org. Chem. 2016, 12, 912–917, doi:10.3762/bjoc.12.89

• [M + H+]. 1-Deoxy-1-(8-hydroxy-2,4-dioxo-2,3,4,10-tetrahydropyrimido[4,5-b]quinoline-10-yl)-D-ribitol (1) A mixture of aldehyde 13 (90 mg, 0.57 mmol), aminouracil 12 (150 mg, 0.57 mmol), NEt3 (0.10 mL, 0.68 mmol) and EtOH (3 mL) was heated in a closed reaction vial at 150 °C for 3 h. After cooling to

The aminoindanol core as a key scaffold in bifunctional organocatalysts

• Isaac G. Sonsona,
• Eugenia Marqués-López and
• Raquel P. Herrera

Beilstein J. Org. Chem. 2016, 12, 505–523, doi:10.3762/bjoc.12.50

• state TS3 was proposed. Herein, the NH from the thioamide and the protonated quinoline moiety would activate and fix the nitroalkene framework through hydrogen-bonding interactions. Simultaneously, the oxygen atom of the hydroxy group would orientate the attack of the indole by the Si face through the

Base metal-catalyzed benzylic oxidation of (aryl)(heteroaryl)methanes with molecular oxygen

• Hans Sterckx,
• Johan De Houwer,
• Carl Mensch,
• Wouter Herrebout,
• Kourosch Abbaspour Tehrani and
• Bert U. W. Maes

Beilstein J. Org. Chem. 2016, 12, 144–153, doi:10.3762/bjoc.12.16

• 9, 19 and 22). Considering the low basicity of compound 3i, 3 equivalents of the stronger acid TFA were used (Table 2, entry 25). Next, the effect of benzoannulation (quinoline) and C–H for N substitution (diazines) in the pyridine ring was studied. Scheme 1 provides an overview of the results for

• the World Health Organization essential medicines list and despite numerous side effects it remains one of the most effective antimalarial drugs on the market [37][38]. Its classical synthesis (Scheme 2, top) is based on the lithiation of 4-bromo-2,8-bis(trifluoromethyl)quinoline (7a) and quenching

• with CO2 resulting in the formation of 2,8-bis(trifluoromethyl)quinoline-4-carboxylic acid (8). Reaction of 8 with in situ generated 2-pyridyllithium (9) finally yields ketone 10 [39]. We considered a new approach based on 4-(pyridin-2-ylmethyl)-2,8-bis(trifluoromethyl)quinoline (12) as the substrate

Solving the puzzling competition of the thermal C²–C⁶ vs Myers–Saito cyclization of enyne-carbodiimides

• Anup Rana,
• Mehmet Emin Cinar,
• Debabrata Samanta and
• Michael Schmittel

Beilstein J. Org. Chem. 2016, 12, 43–49, doi:10.3762/bjoc.12.6

• , M+ − CH3), 246 (47), 245 (100, M+ − N(CH3)2), 244 (20), 243 (26), 231 (14), 218 (15), 203 (18), 183 (62); ESIMS: calcd. for (C19H20N3)+, 290.2; found, 290.2. 3,7-Dimethyl-1-phenyl-1,2,3,4-tetrahydropyrimido[4,5-b]quinoline (12). To 10 mL of dry degassed toluene was added 2-(3-(dimethylamino)prop-1

Enantioselective additions of copper acetylides to cyclic iminium and oxocarbenium ions

• Jixin Liu,
• Srimoyee Dasgupta and
• Mary P. Watson

Beilstein J. Org. Chem. 2015, 11, 2696–2706, doi:10.3762/bjoc.11.290

• observed lower ee’s with Pybox and Box ligands, and only 49% ee with Quinap. However, investigation of novel Pinap ligands led to notably higher ee’s (Scheme 7) [29]. These reaction conditions enable alkynylation of quinoline (20), isoquinoline (21), and pyridine (22) substrates, albeit in lower yields

Beyond catalyst deactivation: cross-metathesis involving olefins containing N-heteroaromatics

• Kevin Lafaye,
• Cyril Bosset,
• Lionel Nicolas,
• Amandine Guérinot and
• Janine Cossy

Beilstein J. Org. Chem. 2015, 11, 2223–2241, doi:10.3762/bjoc.11.241

• it may be suspected that the presence of the two chlorine atoms significantly decreased the basicity of the pyridine (Scheme 21). Tricyclic compound 59 was prepared by a RCM of diene 58 that incorporates a quinoline moiety [61]. In this case, a phenyl group was present at C2 and may be responsible

• catalyst caused by the quinoline (Table 4, entry 4). In their retrosynthesis of haminol A, O’Neil et al. initially envisionned to access the trienic compound using a cross-metathesis/benzoyloxysulfone elimination sequence. The CM would involve 3-vinylpyridine 70 as one of the two partners (Scheme 27) [75

• , biologically relevant conditions were selected (rt, t-BuOH/H2O) and CM involving allyl sulfides that contain functional groups commonly found in DNA-intercalators and N-heteroaromatics were investigated. When a quinoline was present on the allylic sulfide, allylic alcohol was found to be the unique suitable

Recent advances in copper-catalyzed C–H bond amidation

• Jie-Ping Wan and
• Yanfeng Jing

Beilstein J. Org. Chem. 2015, 11, 2209–2222, doi:10.3762/bjoc.11.240

• undertake the amidation to provide indolinone product 28''. An important factor enabling the C–H bond transformation was the presence of the quinoline auxiliary which acted as a bidentate fragment to incorporate the copper catalyst and facilitate the bond cleavage and formation via intermediates A and B

• products 49 or 50 by incorporating phthalimide/saccharin 46. Under the standard conditions, however, the reaction of benzamide with 2-phenylpyridine provided product 51 with low yield (Scheme 14). As a special aromatic system, quinoline N-oxides were well investigated in their reactivity for metal

• -catalyzed C–H activation. Based on the known results of quinoline N-oxide C–H alkenylation [61], arylation [62] and alkylation [63] etc, Li and co-workers [64] investigated and established the C–H amidation of quinoline N-oxides 52 via copper catalysis. According their results, quinoline N-oxides 51

C–H bond halogenation catalyzed or mediated by copper: an overview

• Wenyan Hao and
• Yunyun Liu

Beilstein J. Org. Chem. 2015, 11, 2132–2144, doi:10.3762/bjoc.11.230

• copper-catalyzed arene C–H methoxylation using the generally applicable quinolin-8-yl [40] as DG, Stahl et al. [41] discovered that using a CuCl/LiCl/O2/AcOH catalytic system resulted in the formation of C-5 chlorinated quinoline, demonstrating the pivotal role of the DG in inducing the reaction pathway

• ). Control experiments in the presence of TEMPO suggested that the reaction might proceed via a C-centered free radical provided by SET between the quinoline substrate and the cupric salt. In recent years, the formation of C–F chemical bonds received global research interest owing to the particular functions

• using LiCl. Copper-catalyzed C–H halogenation of 2-arylpyridines using LiX. Copper-mediated selective C–H halogenations of 2-arylpyridine. Copper-catalyzed C–H o-halogenation using removable DG. Copper-catalyzed C–H halogenations using PIP as DG. Copper-catalyzed quinoline C–H chlorination. Copper

Supramolecular chemistry: from aromatic foldamers to solution-phase supramolecular organic frameworks

• Zhan-Ting Li

Beilstein J. Org. Chem. 2015, 11, 2057–2071, doi:10.3762/bjoc.11.222

• predicted, most densely packed lattice for a C5-symmetric macrocycle [49]. Jiang and co-workers also prepared fluorine-containing quinoline oligoamides, which they found self-assembled into unique double and quadruple helices [52][53]. The fluorine atoms in the oligomers induced the backbone to fold by

• confine the rotation of one single bond, while for the latter, it would confine two single bonds. Jiang and Huc and co-workers successfully utilized the five-membered N–H···Cl hydrogen bond to construct quinoline amide-derived double helices [53]. C–H····X (X = OR, F) hydrogen bonding-driven 1,2,3