- Reaction of Diisobutylaluminum Borohydride, a Binary Hydride, with Selected Organic Compounds Containing Representative Functional Groups
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The binary hydride, diisobutylaluminum borohydride [(iBu)2AlBH4], synthesized from diisobutylaluminum hydride (DIBAL) and borane dimethyl sulfide (BMS) has shown great potential in reducing a variety of organic functional groups. This unique binary hydride, (iBu)2AlBH4, is readily synthesized, versatile, and simple to use. Aldehydes, ketones, esters, and epoxides are reduced very fast to the corresponding alcohols in essentially quantitative yields. This binary hydride can reduce tertiary amides rapidly to the corresponding amines at 25 °C in an efficient manner. Furthermore, nitriles are converted into the corresponding amines in essentially quantitative yields. These reactions occur under ambient conditions and are completed in an hour or less. The reduction products are isolated through a simple acid-base extraction and without the use of column chromatography. Further investigation showed that (iBu)2AlBH4 has the potential to be a selective hydride donor as shown through a series of competitive reactions. Similarities and differences between (iBu)2AlBH4, DIBAL, and BMS are discussed.
- Amberchan, Gabriella,Snelling, Rachel A.,Moya, Enrique,Landi, Madison,Lutz, Kyle,Gatihi, Roxanne,Singaram, Bakthan
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supporting information
p. 6207 - 6227
(2021/05/06)
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- Intramolecular Pd-catalyzed reductive amination of enolizable sp3-C-H bonds
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A palladium-catalyzed reductive cyclization of nitroarenes has been designed to construct sp3-C-NHAr bonds from sp3-C-H bonds by using an enolizable nucleophile to intercept a nitrosoarene intermediate. Exposure of ortho-substituted nitroarenes to 5 mol ?% of Pd(OAc)2 and 10 mol ?% of phenanthroline under 2 atm of CO constructs partially saturated 5-, 6-, or 7-membered N-heterocycles using α-pyridyl carboxylates, malonates, 1,3-dimethylbarbituric acid, 1,3-diones, or difurans as the nucleophile.
- Ford, Russell L.,Alt, Isabel,Jana, Navendu,Driver, Tom G.
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supporting information
p. 8827 - 8831
(2019/10/28)
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- Green and convenient protocols for the efficient reduction of nitriles and nitro compounds to corresponding amines with NaBH4 in water catalyzed by magnetically retrievable CuFe2O4 nanoparticles
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Abstract: In this study, firstly, CuFe2O4 nanoparticles were prepared by a simple operation. The structure of the mentioned nanoparticles was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, inductively coupled plasma-optical emission spectrometry, vibrating sample magnetometer and also Brunauer–Emmett–Teller and Barrett–Joyner–Halenda analyses. The prepared magnetically copper ferrite nanocomposite was successfully applied as a simple, cost-effective, practicable, and recoverable catalyst on the green, highly efficient, fast, base-free, and ligand-free reduction of nitriles and also on the affordable and eco-friendly reduction of nitro compounds with the broad substrate scope to the corresponding amines with NaBH4 in water at reflux in high to excellent yields. Graphical abstract: [Figure not available: see fulltext.].
- Zeynizadeh, Behzad,Mohammad Aminzadeh, Farkhondeh,Mousavi, Hossein
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- Palladium-Catalyzed Regioselective Syn-Chloropalladation-Olefin Insertion-Oxidative Chlorination Cascade: Synthesis of Dichlorinated Tetrahydroquinolines
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A palladium catalyzed cascade process involving syn-chloropalladation, intramolecular olefin insertion, and oxidative C-Cl bond formation reactions was demonstrated for the synthesis of dichlorinated tetrahydroquinolines in high yields (up to 93%). The N-propargyl arylamines having a tethered α,β-unsaturated carbonyl moiety underwent a regioselective syn-chloropalladation followed by a Heck-type reaction to deliver the tetrahydroquinoline scaffold. The rare insertion of the second chlorine atom was rationalized comprising a PdII/IV catalytic cycle and oxidative cleavage of the C-PdII bond.
- Vinoth, Perumal,Karuppasamy, Muthu,Vachan,Muthukrishnan, Isravel,Maheswari, C. Uma,Nagarajan, Subbiah,Pace, Vittorio,Roller, Alexander,Bhuvanesh, Nattamai,Sridharan, Vellaisamy
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supporting information
(2019/05/08)
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- Enantioselective Organocatalytic Intramolecular Aza-Diels–Alder Reaction
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A highly efficient catalytic enantioselective intramolecular Povarov reaction was developed with primary anilines as 2-azadiene precursors. A wide variety of angularly fused azacycles were obtained without column chromatography in high to excellent yields and with excellent diastereo- and enantioselectivity (d.r.>99:1 and up to e.r. 99:1). Furthermore, the catalyst loading could be lowered to 1 mol %, and the obtained azacycles could be used as key intermediates for further transformations to generate additional molecular diversity.
- Jarrige, Lucie,Blanchard, Florent,Masson, Géraldine
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supporting information
p. 10573 - 10576
(2017/08/22)
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- Easy Access to Quinolin-2(1 H)-ones via a One-Pot Tandem Oxa-Michael-Aldol Sequence
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An efficient strategy for the synthesis of a variety of quinolin-2(1 H)-one derivatives has been developed. The reaction proceeded from cinnamide derivatives via a tandem reaction in the presence of NaOH to afford the corresponding 2- quinolin-2(1 H)-one derivatives in good to excellent yields.
- Jarrige, Lucie,Merad, Jeremy,Zaied, Siwar,Blanchard, Florent,Masson, Géraldine
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supporting information
p. 1724 - 1728
(2017/10/06)
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- Rh2(II)-catalyzed selective aminomethylene migration from styryl azides
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Rh2(II)-Carboxylate complexes were discovered to promote the selective migration of aminomethylenes in β,β-disubstituted styryl azides to form 2,3-disubstituted indoles. Mechanistic data are also presented that suggest that the migration occurs stepwise before diffusion of the iminium ion.
- Kong, Chen,Jana, Navendu,Driver, Tom G.
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supporting information
p. 824 - 827
(2013/03/29)
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- Discovery of new chemical leads for selective EP1 receptor antagonists
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A series of 4-({2-[alkyl(phenylsulfonyl)amino]phenoxy}methyl)benzoic acids were identified as functional PGE2 antagonists with selectivity for the EP1 receptor subtype starting from a chemical lead 1, which was found while screening our in-house compound library. Discovery of the optimized analogs 21-23 is presented here and structure-activity relationships (SAR) are also discussed.
- Naganawa, Atsushi,Saito, Tetsuji,Nagao, Yuuki,Egashira, Hiromu,Iwahashi, Maki,Kambe, Tohru,Koketsu, Masatoshi,Yamamoto, Hiroshi,Kobayashi, Michiyoshi,Maruyama, Takayuki,Ohuchida, Shuichi,Nakai, Hisao,Kondo, Kigen,Toda, Masaaki
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p. 5562 - 5577
(2007/10/03)
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- Inhibitors of Blood Platelet cAMP Phosphodiesterase. 3. 1,3-Dihydro-2H-imidazoquinolin-2-one Derivatives with Enhanced Aqueous Solubility
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Two series of 1,3-dihydro-2H-imidazoquinolin-2-one derivatives incorporating an additional site for acid salt formation were synthesized and evaluated as inhibitors of human blood platelet cAMP phosphodiesterase (PDE) and ADP-induced platelet aggregation.The objective of this study was to identify compounds that blended potent biological activity with a satisfactory level of aqueous solubility.From a series of 7-aminoimidazoquinolin-2-ones, biological and physical properties were optimally combined in the 1-piperidinyl derivative 11c.However, this compound offered no significant advantage over earlier studied compounds as an antithrombotic agent in an animal model of small vessel thrombosis.A series of 7-alkoxy alkanoic piperazinamide derivatives, in which the additional basic nitrogen atom was remote from the heterocyclic nucleus and accomodated in a secondary binding region of the cAMP PDE enzyme, demonstrated greater intrinsic cAMP PDE inhibitory activity.Structural modifications of this series focused on variation of the piperazine substituent and side-chain length.The lipophilicity of the N-substituent influenced biological potency and aqueous solubility, with substituents of seven carbon atoms or less generally providing acceptable solubility properties.The N-(cyclohexylmethyl)piperazinamide 21h was identified from this series of compounds as a potent inhibitor of platelet cAMP PDE, IC50 = 0.4 nM and ADP-induced platelet aggregation, IC50 = 0.51 μM after a 3-min exposure and 0.1 μM after a 15-min exposure of platelet-rich plasma to the drug.Evaluation of 21h and representative analogues in vivo using a rabbit model of small vessel thrombosis revealed significantly greater antithrombotic efficacy compared to that of previously studied compounds with similar intrinsic biological activity measured in vitro but inferior aqueous solubility.
- Meanwell, Nicholas A.,Dennis, Ronald D.,Roth, Herbert R.,Rosenfeld, Michael J.,Smith, Edward C. R.,et al.
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p. 2688 - 2696
(2007/10/02)
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- 7-amino-1,3-dihydro-2H-imidazo[4,5-b]quinolin 2-ones and method for inhibiting phosphodiesterase and blood platelet aggregation
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Novel series of 2,3-dihydro-2-oxo-1H-imidazo[4,5-b]quinolinyl amine derivatives of Formula STR1 wherein R1 is hydrogen, lower alkyl; R2 is hydrogen, lower alkyl, lower alkoxy, halogen; R3 is hydrogen, lower alkyl; R4 is hydrogen, lower alkyl, alkanoyl, phenylalkanoyl wherein phenyl is optionally substituted with halogen, lower alkyl, lower alkoxy; R3 and R4 are joined together to form morpholinyl, piperidinyl or pyrrolidinyl optionally substituted with --CO2 R5 or STR2 wherein R5 is hydrogen or lower alkyl, and R6 is hydrogen, lower alkyl, cycloalkyl; 4-R7 -piperazinyl wherein R7 is --CO2 R8 wherein R8 is lower alkyl, phenyl optionally substituted with up to 2 halogen, lower alkyl or lower alkoxy; phenylalkanoyl of 7 to 10 carbon wherein phenyl is unsubstituted or independently substituted with up to 2 halogen, lower alkyl, lower alkoxy. The compounds are cyclic AMP phosphodiesterase inhibitors and are particularly useful as inhibitors of blood platelet aggregation and/or as cardiotonic agents.
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