cas 6305-18-6, 2-(4-METHOXYBENZOYL)PYRIDINE

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Photoenzymatic Hydrogenation of Heteroaromatic Olefins Using ‘Ene’-Reductases with Photoredox Catalysts
Flavin-dependent ‘ene’-reductases (EREDs) are highly selective catalysts for the asymmetric reduction of activated alkenes. This function is, however, limited to enones, enoates, and nitroalkenes using the native hydride transfer mechanism. Here we demonstrate that EREDs can reduce vinyl pyridines when irradiated with visible light in the presence of a photoredox catalyst. Experimental evidence suggests the reaction proceeds via a radical mechanism where the vinyl pyridine is reduced to the corresponding neutral benzylic radical in solution. DFT calculations reveal this radical to be “dynamically stable”, suggesting it is sufficiently long-lived to diffuse into the enzyme active site for stereoselective hydrogen atom transfer. This reduction mechanism is distinct from the native one, highlighting the opportunity to expand the synthetic capabilities of existing enzyme platforms by exploiting new mechanistic models.
Biegasiewicz, Kyle F.,Black, Michael J.,Chung, Megan M.,Hyster, Todd K.,Meichan, Andrew J.,Nakano, Yuji,Sandoval, Braddock A.,Zhu, Tianyu
supporting information
p. 10484 - 10488
(2020/04/29)

Carbonylative Suzuki coupling reactions catalyzed by ONO pincer–type Pd(II) complexes using chloroform as a carbon monoxide surrogate
Benzoylhydrazone Schiff base–ligated three new ONO pincer–type palladium(II) complexes, [(PdL1(PPh3)] (1), [(PdL2(PPh3)] (2), and [(PdL3(PPh3)] (3), were synthesized by the reaction of the respective ligand, N-(2-hydroxybenzylidene)benzohydrazide (HL1), N-(2-hydroxy-3-methoxybenzylidene)benzohydrazide (HL2), or N-(5-bromo-2-hydroxybenzylidene) benzohydrazide (HL3), with Pd(OAc)2 and PPh3 in methanol and isolated as air-stable reddish-orange crystalline solids in high yields (78%–83%). All three complexes were fully characterized by elemental analysis, Fourier-transform infrared spectroscopy, UV–Visible, 1H nuclear magnetic resonance (NMR), 13C{1H} NMR, and 31P{1H} NMR spectroscopic studies. The molecular structure of all three complexes was established unambiguously by single-crystal X-ray diffraction studies which revealed a distorted square planar geometry of all three complexes. The ONO pincer–type ligands occupied three coordination sites at the palladium, while the fourth site is occupied by the monodentate triphenylphosphine ligand. The catalytic potential of all three complexes was explored in the carbonylative Suzuki coupling of aryl bromides and iodides with arylboronic acids to yield biaryl ketones, using CHCl3 as the source of carbonyl. The reported protocol is convenient and safe as it obviates the use of carbon monoxide (CO) balloons or pressured CO reactors which are otherwise needed for the carbonylation reactions. The methodology has been successfully applied to the synthesis of two antineoplastic drugs, namely, phenstatin and naphthylphenstatin, in good yields (81% and 85%, respectively). Under the optimized reaction conditions, complex 2 exhibited the best catalytic activity in the carbonylative Suzuki couplings. The reported catalysts have wide reaction scope with good functional group tolerance. All catalysts could be retrieved from the reaction after completion and recycled up to three times with insignificant loss in the catalytic activity.
Layek, Samaresh,Agrahari, Bhumika,Ganguly, Rakesh,Das, Parthasarathi,Pathak, Devendra D.
(2020/01/25)

Method for simply and conveniently synthesizing heterocyclic aryl ketone compound
The invention discloses a method for simply and conveniently synthesizing a heterocyclic aryl ketone compound, and belongs to the technical field of the organic chemistry. The method comprises the following steps: using a benzyl heterocyclic compound as a reaction raw material, in a polar solvent, heating and reacting in an oxygen atmosphere, to obtain a multi-substituted ketone compound. The method is capable of using molecular oxygen as an oxidizing agent, green and environmental, and capable of preparing ketone by directly promoting selective oxidation and functionalization of a Csp3-H bond, and broadening a synthetic method for the ketone compound.
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(2019/01/23)

I-Pr2NMgCl·LiCl Enables the Synthesis of Ketones by Direct Addition of Grignard Reagents to Carboxylate Anions
The direct preparation of ketones from carboxylate anions is greatly limited by the required use of organolithium reagents or activated acyl sources that need to be independently prepared. Herein, a specific magnesium amide additive is used to activate and control the addition of more tolerant Grignard reagents to carboxylate anions. This strategy enables the modular synthesis of ketones from CO2 and the preparation of isotopically labeled pharmaceutical building blocks in a single operation.
Colas, Kilian,Dos Santos, A. Catarina V. D.,Mendoza, Abraham
supporting information

(2019/10/08)

Rhodium-Catalyzed Pyridine N-Oxide Assisted Suzuki-Miyaura Coupling Reaction via C(O)-C Bond Activation
A rhodium-catalyzed Suzuki-Miyaura coupling reaction via C(O)-C bond activation to form 2-benzoylpyridine N-oxide derivatives is reported. Both the C(O)-C(sp2) and C(O)-C(sp3) bond could be activated during the reaction with yields up to 92%. The N-oxide moiety could be employed as a traceless directing group, leading to free pyridine ketones.
Zhong, Jing,Long, Yang,Yan, Xufei,He, Shiyu,Ye, Runyou,Xiang, Haifeng,Zhou, Xiangge
supporting information
p. 9790 - 9794
(2019/12/24)

Site-selective c-h acylation of pyridinium derivatives by photoredox catalysis
A strategy for visible-light-induced site-selective C-H acylation of pyridinium salts was developed by employing N-methoxy-or N-aminopyridinium salts, offering a powerful synthetic tool for accessing highly valuable C2- A nd C4-acylated pyridines. The met
Jung, Sungwoo,Lee, Hyeonyeong,Moon, Yonghoon,Jung, Hoi-Yun,Hong, Sungwoo
p. 9891 - 9896
(2019/10/14)

Photoinduced Divergent Alkylation/Acylation of Pyridine N-Oxides with Alkynes under Anaerobic and Aerobic Conditions
Ortho-alkylated and ortho-acylated pyridines have been conveniently synthesized from pyridine N-oxides and alkynes under visible-light-mediation in a metal-free manner. The alkynes served as both alkylating and acylating agents via switching between anaerobic and aerobic conditions. The overall strategy accommodates a broad scope of substituted pyridine N-oxides and alkynes, with excellent regioselectivity in a number of cases.
Xu, Jin-Hui,Wu, Wen-Bin,Wu, Jie
supporting information
p. 5321 - 5325
(2019/07/08)

A convenient and practical heterogeneous palladium-catalyzed carbonylative Suzuki coupling of aryl iodides with formic acid as carbon monoxide source
A practical heterogeneous palladium-catalyzed carbonylative Suzuki coupling of aryl iodides with arylboronic acids under carbon monoxide gas-free conditions has been developed using a bidentate phosphino-functionalized magnetic nanoparticle-immobilized palladium(II) complex as catalyst. Formic acid was utilized as the carbon monoxide source with dicyclohexylcarbodiimide as the activator, and a wide variety of biaryl ketones were generated in moderate to high yields. The new heterogeneous palladium catalyst can be prepared via a simple procedure and can easily be separated from a reaction mixture by simply applying an external magnet and recycled up to 10 times without any loss of activity.
You, Shengyong,Yan, Chenyu,Zhang, Rongli,Cai, Mingzhong
(2019/01/04)

In situ palladium/N-heterocyclic carbene complex catalyzed carbonylative cross-coupling reactions of arylboronic acids with 2-bromopyridine under CO pressure: efficient synthesis of unsymmetrical arylpyridine ketones and their antimicrobial activities
The carbonylative Suzuki cross-coupling of 2-bromopyridine with various boronic acids to prepare unsymmetrical arylpyridine ketones has been carried out using palladium/N-heterocyclic carbene complexes as catalysts prepared in situ. The selectivity and the rate of these reactions are highly dependent on the conditions, i.e., nature of the palladium catalyst precursor, solvent, temperature and CO pressure. The main side-products arise from direct, non-carbonylative cross-coupling. Under the optimum conditions, arylpyridine ketones are recovered in high yields (60–88%). The antibacterial activities of the corresponding benzimidazole salts 2 were tested against Gram positive and negative bacteria using the agar dilution procedure, and their IC50 values have been determined.
Boubakri,Al-Ayed, Abdullah S.,Mansour,Harrath,Al-Tamimi,?zdemir,Yasar,Hamdi
p. 321 - 328
(2019/01/04)

Conformational Dynamics-Guided Loop Engineering of an Alcohol Dehydrogenase: Capture, Turnover and Enantioselective Transformation of Difficult-to-Reduce Ketones
Directed evolution of enzymes for the asymmetric reduction of prochiral ketones to produce enantio-pure secondary alcohols is particularly attractive in organic synthesis. Loops located at the active pocket of enzymes often participate in conformational changes required to fine-tune residues for substrate binding and catalysis. It is therefore of great interest to control the substrate specificity and stereochemistry of enzymatic reactions by manipulating the conformational dynamics. Herein, a secondary alcohol dehydrogenase was chosen to enantioselectively catalyze the transformation of difficult-to-reduce bulky ketones, which are not accepted by the wildtype enzyme. Guided by previous work and particularly by structural analysis and molecular dynamics (MD) simulations, two key residues alanine 85 (A85) and isoleucine 86 (I86) situated at the binding pocket were thought to increase the fluctuation of a loop region, thereby yielding a larger volume of the binding pocket to accommodate bulky substrates. Subsequently, site-directed saturation mutagenesis was performed at the two sites. The best mutant, where residue alanine 85 was mutated to glycine and isoleucine 86 to leucine (A85G/I86L), can efficiently reduce bulky ketones to the corresponding pharmaceutically interesting alcohols with high enantioselectivities (～99% ee). Taken together, this study demonstrates that introducing appropriate mutations at key residues can induce a higher flexibility of the active site loop, resulting in the improvement of substrate specificity and enantioselectivity. (Figure presented.).
Liu, Beibei,Qu, Ge,Li, Jun-Kuan,Fan, Wenchao,Ma, Jun-An,Xu, Yan,Nie, Yao,Sun, Zhoutong
supporting information
p. 3182 - 3190
(2019/05/15)

Metal-Free Halogen(I) Catalysts for the Oxidation of Aryl(heteroaryl)methanes to Ketones or Esters: Selectivity Control by Halogen Bonding
Metal-free halogen(I) catalysts were used for the selective oxidation of aryl(heteroaryl)methanes [C(sp3)?H] to ketones [C(sp2)=O] or esters [C(sp3)?O]. The synthesis of ketones was performed with a catalytic amount of NBS in DMSO solvent. Experimental studies and density functional theory (DFT) calculations supported the formation of halogen bonding (XB) between the heteroarene and N-bromosuccinimide, which enabled imine–enamine tautomerism of the substrates. No additional activator was required for this crucial step. Isotope-labeling and other supporting experiments suggested that a Kornblum-type oxidation with DMSO and aerobic oxygenation with molecular oxygen took place simultaneously. A background XB-assisted electron transfer between the heteroarenes and halogen(I) catalysts was responsible for the formation of heterobenzylic radicals and, thus, the aerobic oxygenation. For selective acyloxylation (ester formation), a catalytic amount of iodine was employed with tert-butyl hydroperoxide in aliphatic carboxylic acid solvent. Several control reactions, spectroscopic studies, and Time-Dependent Density Functional Theory (TD–DFT) calculations established the presence of acetyl hypoiodite as an active halogen(I) species in the acetoxylation process. With the help of a selectivity study, for the first time we report that the strength of the XB interaction and the frontier orbital mixing between the substrates and acyl hypoiodites determined the extent of the background electron-transfer process and, thus, the selectivity of the reaction.
Guha, Somraj,Sekar, Govindasamy
supporting information
p. 14171 - 14182
(2018/09/10)

Room Temperature Metal-Catalyzed Oxidative Acylation of Electron-Deficient Heteroarenes with Alkynes, Its Mechanism, and Application Studies
Herein, we report an original one-step, simple, room-temperature, regioselective Minisci reaction for the acylation of electron-deficient heteroarenes with alkynes. The method has broad functional group compatibility and gives exclusively monoacylated products in good to excellent yields. The mechanistic pathway was analyzed based on a series of experiments confirming the involvement of a radical pathway. The 18O-labeling experiment suggested that water is a source of oxygen in the acylated product, and head space GC-MS experiment shows the C-C cleavage occurs via release as CO2.
Sharma, Shweta,Kumar, Mukesh,Vishwakarma, Ram A.,Verma, Mahendra K.,Singh, Parvinder Pal
p. 12420 - 12431
(2018/10/20)

Efficient in situ N-heterocyclic carbene palladium(ii) generated from Pd(OAc)2 catalysts for carbonylative Suzuki coupling reactions of arylboronic acids with 2-bromopyridine under inert conditions leading to unsymmetrical arylpyridine ketones: synthesis, characterization and cytotoxic activities
N,N-Substituted benzimidazole salts were successfully synthesized and characterized by 1H-NMR, 13C {1H} NMR and IR techniques, which support the proposed structures. Catalysts generated in situ were efficiently used for the carbonylative cross-coupling reaction of 2 bromopyridine with various boronic acids. The reaction was carried out in THF at 110 °C in the presence of K2CO3 under inert conditions and yields unsymmetrical arylpyridine ketones. All N,N-substituted benzimidazole salts 2a-i and 4a-i studied in this work were screened for their cytotoxic activities against human cancer cell lines such us MDA-MB-231, MCF-7 and T47D. The N,N-substituted benzimidazoles 2e and 2f exhibited the most cytotoxic effect with promising cytotoxic activity with IC50 values of 4.45 μg mL?1 against MDA-MB-231 and 4.85 μg mL?1 against MCF7 respectively.
Touj, Nedra,Al-Ayed, Abdullah S.,Sauthier, Mathieu,Mansour, Lamjed,Harrath, Abdel Halim,Al-Tamimi, Jamil,?zdemir, Ismail,Ya?ar, Sedat,Hamdi, Naceur
p. 40000 - 40015
(2019/01/03)

Copper-Catalyzed Aerobic Oxygenation of Benzylpyridine N-Oxides and Subsequent Post-Functionalization
A copper-catalyzed aerobic oxidation of benzylpyridine N-oxides is reported. The N-oxide moiety acts as a built-in activator for the benzylic methylene oxidation, without requirement of additives. Reaction conditions were identified which suppress undesired benzoylpyridine formation via N-deoxygenation involving intermolecular oxygen transfer. The versatility of the N-oxide group of the benzoylpyridine N-oxide reaction products for post-functionalization of the pyridine ring is demonstrated through efficient C–C, C–N, C–O and C–Cl bond forming procedures, with both nucleophiles and electrophiles. Finally, the applicability of the new synthetic methodology is demonstrated in an alternative route towards the antihistaminic drug Acrivastine via three consecutive N-oxide activated C–H functionalization processes, starting from picoline N-oxide. (Figure presented.).
Sterckx, Hans,Sambiagio, Carlo,Médran-Navarrete, Vincent,Maes, Bert U. W.
supporting information
p. 3226 - 3236
(2017/09/13)

Efficient Selenium-Catalyzed Selective C(sp3)?H Oxidation of Benzylpyridines with Molecular Oxygen
An efficient selenium-catalyzed direct oxidation of benzylpyridines in aqueous DMSO has been successfully developed by using molecular oxygen as the oxidant. A variety of benzoylpyridines with broad functional group tolerance were obtained in modest to excellent yields and with exclusive chemoselectivity. (Figure presented.).
Jin, Weiwei,Zheng, Poonnapa,Wong, Wing-Tak,Law, Ga-Lai
p. 1588 - 1593
(2017/05/05)

Palladium Catalyzed Carbonylative Coupling for Synthesis of Arylketones and Arylesters Using Chloroform as the Carbon Monoxide Source
We describe a modular, palladium catalyzed synthesis of aryl(hetero)aryl benzophenones and aryl benzoates from aryl(hetero)aryl halides using CHCl3 as the carbonyl source in the presence of KOH. The reaction occurs in tandem through an initial carbonylation to generate an aroyl halide, which undergoes coupling with arylboronic acids, bornonates, and phenols. Direct carbonylative coupling of indoles at the third position has also been accomplished under slightly modified reaction conditions by in situ activation of the C-H bond. Notably, CHCl3 is a convenient and safe alternation of CO gas, provides milder reaction conditions with high functional group tolerance, and gives the products in moderate to good yields.
Sharma, Poonam,Rohilla, Sandeep,Jain, Nidhi
p. 1105 - 1113
(2018/06/18)

Direct oxidation of the Csp3–H bonds of N-heterocyclic compounds to give the corresponding ketones using a reusable heterogeneous MnOx-N@C catalyst
Novel reusable MnOx-N@C catalyst has been developed for the direct oxidation of N-heterocycles under solvent-free conditions using TBHP as benign oxidant to give the corresponding N-heterocyclic ketones. The catalytic system exhibited a broad substrate scope and excellent regioselectivity, as well as being amenable to gram-scale synthesis. This MnOx-N@C catalyst also showed good reusability and was successfully recycled six times without any significant loss of activity.
Ren, Lanhui,Wang, Lianyue,Lü, Ying,Li, Guosong,Gao, Shuang
p. 1216 - 1221
(2016/09/07)

Ketone or aldehyde synthetic method by using manganese compound to conduct catalytic oxidation of pyridine compound
The present invention discloses a ketone or aldehyde synthetic method by using a manganese compound to conduct catalytic oxidation of a pyridine compound. Pyridine compounds containing substituent groups are used as a reaction substrate, the manganese compound is used as a catalyst, one or more than two of water, tertiary butanol, acetonitrile, ethyl acetate, or dichloromethane are used as a solvent, a peroxide is used as an oxygen source, a reaction is conducted at a temperature of 25-50 DEG C for 12-48 h, so that the C-H bond of the side chain of the pyridine is oxidized to an ketone or aldehyde by one step, and a reaction crude product is processed to obtain a final product. The preparation method is mild in reaction conditions, less in catalyst use amount, high in atom economy, and simple in operation, has a wide suitable range of substrates, and has industrial applicability.
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(2016/12/01)

One-Pot Directing Group Formation/C?H Bond Functionalization via Copper(I) and Ruthenium(II) Catalysis
A copper(I)-catalyzed oxidation leading to the formation of 2-pyridyl ketone directing groups has been efficiently coupled with a ruthenium(II)-catalyzed C(sp2)?H bond arylation transformation without performing any intermediate work-up. This sustainable approach was further extended to sequential three-step transition metal-catalyzed transformations in which up to four new bonds (C–O, C–C, C–H and O–H) are formed in a one-pot fashion. This is the first example in which two different transition metal catalysts are sequentially employed for the directing group formation and the C?H bond functionalization, respectively. (Figure presented.).
Bruneau, Christian,Gramage-Doria, Rafael
supporting information
p. 3847 - 3856
(2016/12/16)

Palladium-Catalyzed Decarbonylative Cross-Coupling of Azinecarboxylates with Arylboronic Acids
The first palladium-catalyzed decarbonylative coupling of phenyl 2-azinecarboxylates and arylboronic acids is presented. The key for the development of this decarbonylative coupling is the use of Pd/dcype as a catalyst. A wide range of 2-azinecarboxylates can undergo the present coupling reaction to afford 2-arylazines. By combination with previously reported nickel-catalyzed decarbonylative coupling, we achieved a chemoselective sequential decarbonylative coupling of pyridine dicarboxylate to synthesize 2,4-diarylpyridine.
Muto, Kei,Hatakeyama, Taito,Itami, Kenichiro,Yamaguchi, Junichiro
supporting information
p. 5106 - 5109
(2016/10/14)

A Nitrogen-Assisted One-Pot Heteroaryl Ketone Synthesis from Carboxylic Acids and Heteroaryl Halides
A practical and highly effective one-pot synthesis of versatile heteroaryl ketones directly from carboxylic acids and heteroaryl halides under mild conditions is reported. This method does not require derivatization of carboxylic acids (preparation of acid chlorides, Weinreb amides, etc.) or the use of any additives/catalysts. A wide substrate scope of carboxylic acids with high functional group tolerance has also been demonstrated. The results reveal that the presence of an α-nitrogen on the halide substrate greatly improves the desired ketone formation.
Demkiw, Krystyna,Araki, Hirofumi,Elliott, Eric L.,Franklin, Christopher L.,Fukuzumi, Yoonjoo,Hicks, Frederick,Hosoi, Kazushi,Hukui, Tadashi,Ishimaru, Yoichiro,O'Brien, Erin,Omori, Yoshimasa,Mineno, Masahiro,Mizufune, Hideya,Sawada, Naotaka,Sawai, Yasuhiro,Zhu, Lei
p. 3447 - 3456
(2016/05/19)

Synergistic H4NI-AcOH Catalyzed Oxidation of the Csp3-H Bonds of Benzylpyridines with Molecular Oxygen
The oxidation of benzylpyridines forming benzoylpyridines was achieved based on a synergistic H4NI-AcOH catalyst and molecular oxygen in high yield under solvent-free conditions. This is the first nonmetallic catalytic system for this oxidation transformation using molecular oxygen as the oxidant. The catalytic system has a wide scope of substrates and excellent chemoselectivity, and this procedure can also be scaled up. The study of a preliminary reaction mechanism demonstrated that the oxidation of the Csp3-H bonds of benzylpyridines was promoted by the pyridinium salts formed by AcOH and benzylpyridines. The synergistic effect of H4NI-AcOH was also demonstrated by control experiments. (Figure Presented).
Ren, Lanhui,Wang, Lianyue,Lv, Ying,Li, Guosong,Gao, Shuang
supporting information
p. 2078 - 2081
(2015/05/13)

One-pot Unsymmetrical Ketone Synthesis Employing a Pyrrole-Bearing Formal Carbonyl Dication Linchpin Reagent
A one-pot procedure for the synthesis of unsymmetrical ketones utilizing a pyrrole-bearing carbonyl linchpin reagent (carbonyl linchpin N,O-dimethylhydroxylamine pyrrole; CLAmP) is reported. In contrast to other carbonyl dielectrophile equivalents, CLAmP enables the synthesis of ketones from a variety of organolithium and Grignard reagents. The electrophilic nature of CLAmP enables the addition of less reactive as well as thermally unstable nucleophiles. CLAmP was designed to form kinetically stable tetrahedral intermediates upon the addition of organometallic nucleophiles. Evidence for the existence of persistent tetrahedral intermediates was obtained through in situ IR studies.
Heller, Stephen T.,Newton, James N.,Fu, Tingting,Sarpong, Richmond
supporting information
p. 9839 - 9843
(2015/08/19)

Rhodium Catalyzed Asymmetric Hydrogenation of 2-Pyridine Ketones
Catalyzed by [Rh(COD)Binapine]BF4, the asymmetric hydrogenation of 2-pyridine ketones has been achieved with excellent enantioselectivities (enantiomeric excesses up to 99%) under mild conditions. This method is suitable for various kinds of 2-pyridine ketones and their derivatives. A number of enantiomerically pure chiral 2-pyridine-aryl/alkyl alcohols were prepared through hydrogenation, which can be used directly in organic synthesis.
Yang, Hailong,Huo, Ningning,Yang, Ping,Pei, Hao,Lv, Hui,Zhang, Xumu
supporting information
p. 4144 - 4147
(2015/09/15)

Copper-catalyzed oxidative amination of sp3 C-h bonds under air: Synthesis of 1,3-diarylated imidazo[1,5-a ]pyridines
A copper(II)-catalyzed tandem reaction between pyridine ketone and benzylamine was developed by using clean O2 as an oxidant. This transformation proceeded via an efficient condensation-amination-oxidative dehydrogenation process, affording 1,3-diarylated imidazo[1,5-a]pyridines in excellent yields.
Wang, Huiqiao,Xu, Wentao,Wang, Zhiqiang,Yu, Lintao,Xu, Kun
p. 2431 - 2435
(2015/04/14)

Facile one-pot synthesis of [1,2,3]triazolo[1,5-a]pyridines from 2-acylpyridines by copper(II)-catalyzed oxidative N-N bond formation
An efficient and simple method for the synthesis of various [1,2,3]triazolo[1,5-a]pyridines has been established. The method involves a copper(II)-catalyzed oxidative N-N bond formation that uses atmospheric oxygen as the terminal oxidant following hydrazonation in one pot. The use of ethyl acetate as the solvent dramatically promotes the oxidative N-N bond-formation reaction and enables the application of oxidative cyclization in the efficient one-pot reaction. A mechanism for the reaction was proposed on the basis of the results of a spectroscopic study. In the same pot: [1,2,3]Triazolo[1,5-a] pyridines are synthesized from the corresponding 2-acylpyridines by a one-pot method, consisting of hydrazonation followed by oxidative cyclization through copper(II)-catalyzed N-N bond formation (see scheme).
Hirayama, Tasuku,Ueda, Satoshi,Okada, Takahiro,Tsurue, Norihiko,Okuda, Kensuke,Nagasawa, Hideko
supporting information
p. 4156 - 4162
(2014/04/17)

Isolation and characterization of a trinuclear cobalt complex containing trigonal-prismatic cobalt in secondary alcohol aerobic oxidation
An unusual trinuclear cobalt complex was successfully isolated and characterized in the Co(OAc)2·4H2O-catalyzed aerobic oxidation of pyridine-based secondary alcohols. In this complex, a cobalt ion (the one in the middle, labeled Co2) has a novel trigonal-prismatic structure coordinated with six oxygen atoms from the substrate. The molecular oxygen present in air plays a major role in enabling this transformation to be catalytic. This aerobic catalytic reaction is very selective to pyridine-based secondary alcohols over primary alcohols.
Karthikeyan,Alamsetti,Sekar
p. 1665 - 1671
(2014/05/06)

Rhodium-catalyzed NH insertion of pyridyl carbenes derived from pyridotriazoles: A general and efficient approach to 2-picolylamines and imidazo[1,5-a]pyridines
A general and efficient NH insertion reaction of rhodium pyridyl carbenes derived from pyridotriazoles was developed. Various NH-containing compounds, including amides, anilines, enamines, and aliphatic amines, smoothly underwent the NH insertion reaction to afford 2-picolylamine derivatives. The developed transformation was further utilized in a facile one-pot synthesis of imidazo[1,5-a]pyridines.
Shi, Yi,Gulevich, Anton V.,Gevorgyan, Vladimir
supporting information
p. 14191 - 14195
(2015/01/09)

Synthesis of aryl(di)azinyl ketones through copper- and iron-catalyzed oxidation of the methylene group of aryl(di)azinylmethanes
Sustainable Oxidations: An oxidation method to transform aryl(di)azinylmethanes into aryl(di)azinyl ketones is described. Base metals (copper and iron) as catalysts in combination with O2 as the oxidant are used, which makes this method sustainable. The utility of this method is illustrated by the synthesis of 6-(4-methylbenzoyl)pyridine-2-carbaldehyde, which is an intermediate in the preparation of the drug Acrivastine. Copyright
De Houwer, Johan,Abbaspour Tehrani, Kourosch,Maes, Bert U. W.
supporting information; experimental part
p. 2745 - 2748
(2012/04/10)

Triazolopyridines. Part 29. Direct arylation reactions with [1,2,3]triazolo[1,5-a]pyridines
[1,2,3]Triazolo[1,5-a]pyridine reacts with aryl halides in presence of catalytic amounts of Pd(OAc)2 and PPh3 in DMF to give, in medium or low yield, direct arylations in C3 and pyridyl aryl ketones. Thiazole and benzothiazole have been directly arylated using 7-halotriazolopyridines. These behaviours are unprecedented in the chemistry of [1,2,3]triazolo[1,5-a] pyridines. ARKAT-USA, Inc.
Abarca, Belen,Adam, Rosa,Ballesteros, Rafael,Chiassai, Leonardo,Gamon, Cristina
p. 229 - 241
(2013/02/25)

Ruthenium-catalyzed enantioselective hydrogenation of aryl-pyridyl ketones
Various substituted aryl-pyridyl ketones were hydrogenated in the presence of Ru-XylSunPhos-Daipen bifunctional catalytic system with enantiomeric excesses up to 99.5%. Upon introduction of a readily removable ortho-bromo atom to the phenyl ring, enantiomerically enriched 4-chlorophenylpyridylmethanol was obtained by hydrogenation method with 97.3% ee, which provided an important chiral intermediate for some histamine H1 antagonists.
Tao, Xiaoming,Li, Wanfang,Ma, Xin,Li, Xiaoming,Fan, Weizheng,Xie, Xiaomin,Ayad, Tahar,Ratovelomanana-Vidal, Virginie,Zhang, Zhaoguo
experimental part
p. 612 - 616
(2012/03/26)

Aerobic oxidation of secondary benzylic alcohols and direct oxidative amidation of aryl aldehydes promoted by sodium hydride
We reported herein new reactivities and possible mechanistic implications of a simplest oxidant (NaH/air) uncovered on a broad range of useful transformations, including aerobic alcohol oxidations, allylic alcohol isomerizations and oxidations, cyclopropyl alcohol fragmentations, and direct aryl aldehyde oxidative amidations. These readily implementable transition-metal-free processes feature exceptional material accessibility, operational simplicity, and environmental compatibility, and add new dimensions to its synthetic utilities that are fairly robust yet had not previously been fully realized and systematically explored.
Wang, Xinbo,Wang, David Zhigang
supporting information; experimental part
p. 3406 - 3411
(2011/06/17)

AMINOPYRIDINE AND CARBOXYPYRIDINE COMPOUNDS AS PHOSPHODIESTERASE 10 INHIBITORS
Pyridine and pyrimidine compounds: or a pharmaceutically acceptable salt thereof, wherein m, n, R1, R2, R3, R4, R5, R6, R7, X1, X2, X3, X4, X5, X6, X7, X8, and Y are as defined in the specification; or a pharmaceutically acceptable salt thereof, wherein ring A, m, n, y, R2, R3, R4, R5, R6, R7, R8, R9, X1, X2, and ring A are as defined in the specification; and or a pharmaceutically acceptable salt thereof, wherein m, n, y, R2, R3, R4, R5, R6, R7, R9, X1, X2, and ring A are as defined in the specification; compositions containing them, and processes for preparing such compounds. Provided herein also are methods of treating disorders or diseases treatable by inhibition of PDE10, such as obesity, non-insulin dependent diabetes, schizophrenia, bipolar disorder, obsessive-compulsive disorder, and the like.
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(2010/07/04)

Synthesis of fluorescent 1,3-diarylated imidazo[1,5-α]pyridines: Oxidative condensation-cyclization of aryl-2-pyridylmethylamines and aldehydes with elemental sulfur as an oxidant
Oxidative condensation - cyclization of aldehydes and aryl-2- pyridylmethylamines proceeded in the presence of a stoichiometric amount of elemental sulfur as an oxidant in the absence of catalyst. The reaction gave a variety of 1,3-diarylated imidazo[l,5-a]pyridines in good to high yields. The products showed fluorescence emission in a wavelength range of 454-524 nm. The quantum yields of 1,3-diarylated imidazopyridines were greatly improved compared to those of the parent 3-monosubstituted compounds.
Shibahara, Fumitoshi,Sugiura, Rie,Yamaguchi, Eiji,Kitagawa, Asumi,Murai, Toshiaki
supporting information; experimental part
p. 3566 - 3568
(2009/09/05)

Slow-onset, long-duration, alkyl analogues of methylphenidate with enhanced selectivity for the dopamine transporter
Methylphenidate analogues, in which the carbomethoxy has been replaced by an alkyl group and with different phenyl substituents, have been synthesized and tested in monoamine transporter assays. As predicted from a pharmacophore model, most of the RR/SS diastereomers showed high potency as dopamine reuptake inhibitors. Analogues with a 4-chlorophenyl group and an unbranched initial alkyl atom had consistently enhanced selectivity for the dopamine transporter. The most potent compounds were those with a three- or four-carbon chain. The "inactive" RS/SR diastereomers showed substantial activity when the phenyl substituent was 3,4-dichloro. On a locomotor assay, one compound was found to have a slow onset and a long duration of action. The activity of these compounds provides additional evidence for a conformational/superposition model of methylphenidate with cocaine-like structures. A ketone analogue, obtained by hydrogenating a previously described vinylogous amide, had activity similar to that of methylphenidate.
Froimowitz, Mark,Gu, Yonghong,Dakin, Les A.,Nagafuji, Pamela M.,Kelley, Charles J.,Parrish, Damon,Deschamps, Jeffrey R.,Janowsky, Aaron
p. 219 - 232
(2007/10/03)

Palladium-N-heterocyclic carbene an efficient catalytic system for the carbonylative cross-coupling of pyridine halides with boronic acids
Carbonylative cross-coupling of different pyridyl halides with various boronic acids was studied using catalytic systems constituted of N-heterocyclic carbene type ligands and palladium. These systems easily obtained in situ from the corresponding imidazolium salt and palladium acetate appear more efficient toward bromopyridines than catalysts based on hindered and basic alkylphosphines such as tricyclohexylphosphine. Their higher efficiency was also evidenced by coupling using chloro- or dichloropyridines and chloroquinolines, which practically do not react with catalytic systems based on phosphines.
Maerten, Eddy,Sauthier, Mathieu,Mortreux, André,Castanet, Yves
p. 682 - 689
(2007/10/03)

Solvent-free catalytic Friedel - Crafts acylation of aromatic compounds with carboxylic acids by using a novel heterogeneous catalyst system: p-Toluenesulfonic acid/graphite
TsOH/graphite was found to be an effective catalyst system for the Friedel-Crafts acylation of aromatic compounds with carboxylic acids. Both aliphatic and aromatic carboxylic acids reacted smoothly under TsOH/graphite catalysis to afford the corresponding aromatic ketones in high yields. The graphite was easily recovered by simple extraction and could be reused without decrease of activity in the presence of fresh TsOH.
Sarvari, Mona Hosseini,Sharghi, Hashem
p. 2282 - 2287
(2007/10/03)

Simple and improved procedure for the regioselective acylation of aromatic ethers with carboxylic acids on the surface of graphite in the presence of methanesulfonic acid
Friedel-Crafts acylation of aromatic compounds such as anisole has been successfully carried out using the combination of graphite with MeSO 3H. Both aromatic and aliphatic carboxylic acids reacted smoothly under the conditions to afford the corresponding aromatic ketones in high yield.
Sarvari, Mona Hosseini,Sharghi, Hashem
p. 2165 - 2168
(2007/10/03)

Ru3(CO)12-Catalyzed intermolecular cyclocoupling of ketones, alkenes or alkynes, and carbon monoxide. [2 + 2 + 1] Cycloaddition strategy for the synthesis of functionalized γ-butyrolactones
The ruthenium-catalyzed intermolecular cyclocoupling of ketones (or aldehydes), alkenes (or alkynes), and CO, which leads to γ-butyrolactones, is described. The reaction represents the first example of the catalytic synthesis of heterocycles via an interm
Tobisu,Chatani,Asaumi,Amako,Ie,Fukumoto,Murai
p. 12663 - 12674
(2007/10/03)

3-SUBSTITUTED-4-HYDROXYPHENYL-2-PIPERIDYLCARBINOLS AS BETA ADRENERGIC STIMULANTS
3-Substituted-3-hydroxyphenyl-2-piperidylcarbinols are prepared. These compounds are β-adrenergic stimulants and are useful in particular as bronchodilators.
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(2008/06/13)