- Cobalt-Catalyzed Deoxygenative Hydroboration of Nitro Compounds and Applications to One-Pot Synthesis of Aldimines and Amides
-
The commercially available and bench-stable Co(acac)2 ligated with bis[(2-diphenylphosphino)phenyl] ether (dpephos) was employed for selective room temperature hydroboration of nitro compounds with HBPin (TOF up to 4615 h?1), tolerating halide, hydroxy, amino, ether, ester, lactone, amide and heteroaromatic functionalities. These reactions offered a direct access to a variety of N-borylamines RN(H)BPin, which were in situ treated with aldehydes and carboxylic acids to produce a series of aldimines and secondary carboxamides without the need for dehydrating and/or coupling reagents. Combination of these transformations in a sequential one-pot manner allowed for direct and selective synthesis of aldimines and secondary carboxamides from readily available and inexpensive nitro compounds.
- Gudun, Kristina A.,Hayrapetyan, Davit,Khalimon, Andrey Y.,Segizbayev, Medet,Slamova, Ainur,Zakarina, Raikhan
-
-
- Hydrosilylative reduction of primary amides to primary amines catalyzed by a terminal [Ni-OH] complex
-
A terminal [Ni-OH] complex1, supported by triflamide-functionalized NHC ligands, catalyzes the hydrosilylative reduction of a range of primary amides into primary amines in good to excellent yields under base-free conditions with key functional group tolerance. Catalyst1is also effective for the reduction of a variety of tertiary and secondary amides. In contrast to literature reports, the reactivity of1towards amide reduction follows an inverse trend,i.e., 1° amide > 3° amide > 2° amide. The reaction does not follow a usual dehydration pathway.
- Bera, Jitendra K.,Pandey, Pragati
-
supporting information
p. 9204 - 9207
(2021/09/20)
-
- Green method for catalyzing reduction reaction of aliphatic nitro derivative
-
The invention relates to a green method for catalyzing reduction reaction of aliphatic nitro derivatives. According to the method, non-transition metal compounds, namely triethyl boron and potassium tert-butoxide, are used as a catalytic system for the first time, an aliphatic nitro derivative and pinacolborane which is low in price and easy to obtain are catalyzed to be subjected to a reduction reaction under mild conditions, and an aliphatic amine hydrochloride product is synthesized after acidification with a hydrochloric acid aqueous solution. Compared with a traditional method, the method generally has the advantages that the catalyst is cheap and easy to obtain, operation is convenient, and reaction is safe. The selective reduction reaction of the aliphatic nitro derivative catalyzed by the non-transition metal catalyst and pinacol borane is realized for the first time, and the aliphatic amine hydrochloride product is synthesized through acidification treatment of the hydrochloric acid aqueous solution, so that a practical new reaction strategy is provided for laboratory preparation or industrial production.
- -
-
Paragraph 0005-0006; 0013-0016
(2021/07/31)
-
- Transition metal-free catalytic reduction of primary amides using an abnormal NHC based potassium complex: Integrating nucleophilicity with Lewis acidic activation
-
An abnormal N-heterocyclic carbene (aNHC) based potassium complex was used as a transition metal-free catalyst for reduction of primary amides to corresponding primary amines under ambient conditions. Only 2 mol% loading of the catalyst exhibits a broad substrate scope including aromatic, aliphatic and heterocyclic primary amides with excellent functional group tolerance. This method was applicable for reduction of chiral amides and utilized for the synthesis of pharmaceutically valuable precursors on a gram scale. During mechanistic investigation, several intermediates were isolated and characterized through spectroscopic techniques and one of the catalytic intermediates was characterized through single-crystal XRD. A well-defined catalyst and isolable intermediate along with several stoichiometric experiments, in situ NMR experiments and the DFT study helped us to sketch the mechanistic pathway for this reduction process unravelling the dual role of the catalyst involving nucleophilic activation by aNHC along with Lewis acidic activation by K ions.
- Bhunia, Mrinal,Sahoo, Sumeet Ranjan,Das, Arpan,Ahmed, Jasimuddin,Sreejyothi,Mandal, Swadhin K.
-
p. 1848 - 1854
(2020/03/03)
-
- NNP-Type Pincer Imidazolylphosphine Ruthenium Complexes: Efficient Base-Free Hydrogenation of Aromatic and Aliphatic Nitriles under Mild Conditions
-
A series of seven novel NImNHP-type pincer imidazolylphosphine ruthenium complexes has been synthesized and fully characterized. The use of hydrogenation of benzonitrile as a benchmark test identified [RuHCl(CO)(NImNHPtBu)] as the most active catalyst. With its stable Ru-BH4 analogue, in which chloride is replaced by BH4, a broad range of (hetero)aromatic and aliphatic nitriles, including industrially interesting adiponitrile, has been hydrogenated under mild and base-free conditions.
- Adam, Rosa,Alberico, Elisabetta,Baumann, Wolfgang,Drexler, Hans-Joachim,Jackstell, Ralf,Junge, Henrik,Beller, Matthias
-
p. 4991 - 5002
(2016/04/05)
-
- Synthesis of transparent aminosilane-derived silica based networks for entrapment of sensitive materials
-
A novel sol-gel synthesis route is reported which results in the formation of optically transparent silica based hydro- and xerogels from an aminosilane precursor in aqueous solutions. These materials can be used for entrapment of microalgae and light-harvesting complex (LHC) samples. The Royal Society of Chemistry 2013.
- Mueller, Christiane,Kraushaar, Konstantin,Doebbe, Anja,Mussgnug, Jan H.,Kruse, Olaf,Kroke, Edwin,Patel, Anant V.
-
p. 10163 - 10165
(2013/10/22)
-
- A catalytic version of hypervalent aryl-λ3-iodane-induced Hofmann rearrangement of primary carboxamides: Iodobenzene as an organocatalyst and m-chloroperbenzoic acid as a terminal oxidant
-
The first catalytic version of hypervalent aryl-λ3- iodane-induced Hofmann rearrangement of primary carboxamides, which probably involves in situ generation of a tetracoordinated bis(aqua)(hydroxy)phenyl- λ3-iodane complex as an active oxidant from a catalytic amount of iodobenzene by the reaction with m-chloroperbenzoic acid in the presence of HBF4 in dichloromethane-water under mild conditions, was developed.
- Miyamoto, Kazunori,Sakai, Yuuta,Goda, Shunsuke,Ochiai, Masahito
-
supporting information; experimental part
p. 982 - 984
(2012/02/04)
-
- Zinc/hydrazine: A low cost-facile system for the reduction of nitro compounds
-
The nitro group in aliphatic and aromatic nitro compounds also containing reducible substituents such as ethene, nitrile, carboxylic acid, phenol, halogen, ester etc., are selectively and rapidly reduced at room temperature to corresponding amines in good yields by employing 99-100% hydrazine hydrate, in the presence of commercial zinc dust. It was observed that, this system is equally compatible with existing methods, which employ expensive catalysts like palladium, platinum, ruthenium etc.
- Gowda, Shankare,Gowda, D. Channe
-
p. 180 - 183
(2007/10/03)
-
- Hydrazinium monoformate: A new hydrogen donor. Selective reduction of nitrocompounds catalyzed by commercial zinc dust
-
The nitro group in aliphatic and aromatic nitro compounds also containing reducible substituents such as ethene, nitrile, acid, phenol, halogen, ester, etc., are selectively and rapidly reduced at room temperature to corresponding amines in good yields by employing hydrazinium monoformate, in the presence of commercial zinc dust. It was observed that, hydrazinium monoformate is more effective than hydrazine or formic acid and reduction of nitro group occurs without hydrogenolysis in the low cost zinc dust compared to expensive metals like palladium.
- Gowda, Shankare,Gowda, B. K. Kempe,Gowda, D. Channe
-
p. 281 - 289
(2007/10/03)
-
- Nickel-catalyzed formic acid reductions. A selective method for the reduction of nitro compounds
-
Aliphatic and aromatic nitro compounds were selectively reduced to their corresponding amino derivatives in good yields using formic acid and raney nickel. This system is found to be compatible with several sensitive functionalities such as halogens, -OH, -OCH3, -CHO, -COCH3-COC6H5, -COOH, -COOC2H5, -CONH2, -CN, -CH=CH-COOH, -NHCOCH3. The reduction can be carrid out not only with HCOOH but also with HCOONH4.
- Channe Gowda,Prakasha Gowda,Ramesha Baba,Gowda, Shankare
-
p. 2889 - 2895
(2007/10/03)
-
- Oxidative deprotection of diphenylmethylamines
-
(formula presented) The diphenylmethyl amino protecting group can be efficiently removed by initial oxidation of the amine to an imine by 2,3-dichloro-5,6-dicyanobenzoquinone. The resulting imine can then be easily hydrolyzed under mildly acidic conditions. This method is particularly well suited for the preparation of α-amino phosphinates and α-amino phosphonates.
- Sampson, Peter B.,Honek, John F.
-
p. 1395 - 1397
(2008/02/09)
-
- Incorporation and Deoxygenation of Carbon Dioxide: A Metal-Assisted Facile Conversion of Carbon Dioxide and Primary Amines to Isocyanates
-
Metal N-alkylcarbamato complexes (M = Na, n = 1; M = Mn, Co, n =2) were prepared by treating CO2 with a primary amine RNH2 (R = Ph, Cy, Pr) and various complex precursors.For M = Mn or Co and R = Cy, MCl2 can be used as starting material.These complexes were readily decomposed by acyl halides R'COCl (R' = Ph, Me), and two reaction pathways were observed.One led to decarboxylation and formation of amides RNHC(O)R', while the other afforded isocyanate RNCO and carboxylic acid (M = Na) or carboxylic anhydride (M = Mn, Co).Analysis of the reaction products showed that the metal plays a major role in the formation of the isocyanate, intercepting one of the reaction products.A mechanistic rationalization is proposed.
- Belforte, Antonio,Dell'Amico, Daniela Belli,Calderazzo, Fausto
-
p. 1891 - 1898
(2007/10/02)
-
- A GENERAL PROCEDURE FOR MILD AND RAPID REDUCTION OF ALIPHATIC AND AROMATIC NITRO COMPOUNDS USING AMMONIUM FORMATE AS A CATALYTIC HYDROGEN TRANSFER AGENT
-
Various aliphatic and aromatic nitro compounds were selectively and rapidly reduced to their corresponding amino derivatives in very good yield using anhydrous ammonium formate as a catalytic hydrogen transfer agent.
- Ram, Siya,Ehrenkaufer, Richard E.
-
p. 3415 - 3418
(2007/10/02)
-
- A Simple Synthesis pf Primary Amines via their N,N-Bis(trimethylsilyl) Derivatives
-
Primary halogen compounds 1 or the corresponding tosylates react with sodium bis(trimethylsilyl)amide (2) in hexamethyldisilazane to form N,N-bis(trimethylsilyl)amines 3, which are converted into the amine hydrochlorides 5 by treatment with aqueous HCl.
- Bestmann, Hans Juergen,Woelfel, Gerhard
-
p. 1250 - 1254
(2007/10/02)
-
- Lithiation of α-Nitrosaminoalkyl Ethers. Synthetic Equivalents of α-Primary Amino Carbanions
-
Successful experiments directed toward the C-1 alkylation and hydroxyalkylation of primary amines are reported.Primary amines are converted into their N-nitroso-N-(1-methoxyethyl) derivatives, which are subsequently lithiated and condensed with various electrophiles, denitrosated, and hydrolyzed to produce the desired compounds in good to excellent yields.
- Saavedra, Joseph E.
-
p. 2388 - 2392
(2007/10/02)
-
- Substituent Effects on Tautomerisation Constants of Alkylaryltriazenes
-
Both tautomers of propyl-p-nitrophenyl-, -p-cyanophenyl-, -3,5-dichlorophenyl-, and -p-chlorophenyl-triazenes are directly observable by 1H n.m.r. at 200 MHz in CD3CN at 25 deg C.In addition, lower temperature studies enable the two tautomers of propyl-p-methylphenyl- and -p-methoxyphenyl-triazenes to be quantitated.At -45 deg C rotamers about the N-N bond of the conjugated tautomers are also separately observable. 13C N.m.r. studies of the p-nitro- and p-chloro-compounds suggest tautomerisation involves the less abundant rotamer of the conjugated tautomer and the unconjugated tautomer.The position of equilibrium at 25 deg C is described by log (/) = (0.67 +/- 0.13) - (0.31 +/- 0.04)pKa (ArNH3+). 13C, as well as 1H n.m.r. studies indicate that change of solvent to (CD3)2SO, CD3CN-(CD3)2SO, or CD3CN-(CD3)2SO-H2O has little effect.Neither, in the p-nitrophenyl case, does change of the propyl group for benzyl.
- Kelly, Miguel A.,Murray, Martin,Sinnott, Michael L.
-
p. 1649 - 1654
(2007/10/02)
-
- Carbamate derivatives and method for manufacture thereof
-
Novel carbamate derivatives and a method for the manufacture thereof are disclosed. The carbamate derivatives or insecticidal compositions containing such carbamate derivatives as the active component exhibit an outstanding insecticidal effect on the organophosphorus or carbamate resistant green rice leafhoppers (Nephotettix cincticeps Uhler).
- -
-
-
