- 2-catalyzed directed N -Boc amidation of arenes "on water"
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Rhodium(III) catalysis "on water" is effective for directed C-H amidation of arenes. The catalytic process is promoted by OH groups present on the hydrophobic water surface and is inefficient in all (most) common organic solvents investigated so far. In the presence of easily prepared tert-butyl 2,4-dinitrophenoxycarbamate, a new and stable nitrene source, the "on water" reaction can efficiently provide the desired N-Boc-aminated products with good functional group tolerance.
- Ali, Md Ashif,Yao, Xiayin,Sun, Hao,Lu, Hongjian
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supporting information
p. 1513 - 1516
(2015/03/30)
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- Mn-catalyzed aromatic C-H alkenylation with terminal alkynes
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The first manganese-catalyzed aromatic C-H alkenylation with terminal alkynes is described. The procedure features an operationally simple catalyst system containing commercially available MnBr(CO)5 and dicyclohexylamine (Cy2NH). The reaction occurs readily in a highly chemo-, regio-, and stereoselective manner delivering anti-Markovnikov E-configured olefins in high yields. Experimental study and DFT calculations reveal that (1) the reaction is initiated by a C-H activation step via the cooperation of manganese and base; (2) manganacycle and alkynylmanganese species are the key reaction intermediates; and (3) the ligand-to-ligand H-transfer and alkynyl-assisted C-H activation are the key steps rendering the reaction catalytic in manganese.
- Zhou, Bingwei,Chen, Hui,Wang, Congyang
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p. 1264 - 1267
(2013/03/14)
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- Facile diversity-oriented synthesis and antitubercular evaluation of novel aryl and heteroaryl tethered pyridines and dihydro-6H-quinolin-5-ones derived via variants of the Bohlmann-Rahtz reaction
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The diversity oriented synthesis of substituted pyridines and dihydro-6H-quinolin-5-ones tethered with aryls and heteroaryls was achieved in very good yields through CeCl3?7H2O-NaI catalyst via variants of the Bohlmann-Rahtz reaction
- Kantevari, Srinivas,Patpi, Santhosh Reddy,Addla, Dinesh,Putapatri, Siddamal Reddy,Sridhar, Balasubramanian,Yogeeswari, Perumal,Sriram, Dharmarajan
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scheme or table
p. 427 - 435
(2011/09/14)
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- PIPERIDINE ARYL SULFONAMIDE DERIVATIVES AS Kv1.3 MODULATORS
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Compounds of the formula (I), or pharmaceutically acceptable salts thereof, wherein m, n, p, X, R1, R2, R3, R4 R5 and R6 are as defined herein. Also disclosed are methods of making the comp
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Page/Page column 55-56
(2011/07/07)
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- PIPERIDINE ARYL SULFONAMIDE DERIVATIVES AS KV1.3 MODULATORS
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Compounds of the formula (I) or pharmaceutically acceptable salts thereof, wherein m, R1, R2, R3, R4 and R5 are as defined herein. Also disclosed are methods of making the compounds and using the comp
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Page/Page column 62-63
(2011/07/07)
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- Microwave-assisted diversity-oriented domino synthesis of functionalized nicotinic acid derivatives
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The microwave-assisted diversity-oriented domino synthesis of functionalized alkyl nicotinates from propargyl vinyl ethers is described. The domino manifold comprises a complex network of reactions involving at least five distinct chemical steps. The obtained alkyl nicotinates incorporate two diversity points at the ring and one ester functionality as convenient handles for further elaboration. Copyright
- Tejedor, David,Mendez-Abt, Gabriela,Garcia-Tellado, Fernando
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experimental part
p. 6582 - 6587
(2011/02/24)
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- A convenient domino access to substituted alkyl 1,2-dihydropyridine- 3carboxylates from propargyl enol ethers and primary amines
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A convenient domino access to substituted alkyl 1,2-dihydropyridine-3- carboxylates from propargyl enol ethers and primary amines was reported. A solution of propargyl sinyl ether 1a and p-anisidine in toluene was placed in a microwave-special closed vial and the solution was irradiated for 30 minutes in a single-mode microwave oven. The reaction mixture was dried over anhydrous sodium sulfate and filtrated using dichloromethane as solvent. After removing the solvent at reduced pressure the products were purified by flash column chromatography. Accordingly, the microwave irradiation of an ethanolic mixture of propargyl enol ether 1 a and MeONH2.HCl in the presence of NaOAc yielded the methyl 2-phenyl-4-pyridinecarboxylate in a convenient 54% yield. These results seem to point out to a new reaction pathway involving different thermally-driven rearrangements of the 2,4-dienal 3 intermediate.
- Tejedor, David,Mendez-Abt, Gabriela,Garcia-Tellado, Fernando
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supporting information; experimental part
p. 428 - 431
(2010/06/13)
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- Reaction of N-vinylic phosphazenes with α,β-unsaturated aldehydes. Azatriene-mediated synthesis of dihydropyridines and pyridines derived from β-amino acids
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Aza-Wittig reaction of N-vinylic phosphazenes (1,2 addition), derived from diphenylmethylphosphine or derived from trimethylphosphine with α,β-unsaturated aldehydes, leads to the formation of 3-azatrienes through a [2 + 2]-cycloaddition-cycloreversion sequence. The presence of an alkyl substituent in position 3 of N-vinylic phosphazenes increases the steric interactions, and [4 + 2] periselectivity (1,4 addition) is observed. Reaction of azatrienes with α,β-unsaturated aldehydes yields pyridines.
- Palacios, Francisco,Herran, Esther,Alonso, Concepcion,Rubiales, Gloria,Lecea, Begona,Ayerbe, Mirari,Cossio, Fernando P.
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p. 6020 - 6030
(2007/10/03)
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- Syntheses of substituted pyridines, quinolines and diazines via palladium-catalyzed cross-coupling of aryl Grignard reagents
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The palladium-catalyzed cross-coupling reactions between arylmagnesium halides (phenylmagnesium chloride, mesitylmagnesium bromide, 4-(methoxycarbonyl)phenylmagnesium chloride and 4-cyanophenylmagnesium chloride) and halopyridines allowed the synthesis of substituted pyridines. Owing to the remarkably mild conditions used (often below 0°C), the reaction could be extended to the use of functionalized halopyridines, haloquinolines and halodiazines.
- Bonnet, Véronique,Mongin, Florence,Trécourt, Fran?ois,Quéguiner, Guy,Knochel, Paul
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p. 4429 - 4438
(2007/10/03)
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- Preparation of polyfunctional pyridines by a palladium(0)-catalyzed cross-coupling of functionalized aryl Grignard reagents
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Difunctionalized pyridines can be prepared by a Pd(0)-catalyzed cross-coupling of functionalized arylmagnesium compounds with chloro- or bromopyridines at temperatures as low as -40°C. An addition-elimination mechanism involving a palladate intermediate is proposed.
- Bonnet, Véronique,Mongin, Florence,Trécourt, Francois,Quéguiner, Guy,Knochel, Paul
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p. 5717 - 5719
(2007/10/03)
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- Unusual reactivity of (vinylimino)phosphoranes and their utility in the preparation of pyridine and dihydropyridine derivatives
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New reactions of (vinylimino)phosphoranes with aldehydes involving an initial nucleophilic attack of the β-carbon atom of the vinyl side chain on the carbonyl carbon atom are reported. Iminophosphorane 4 derived from ethyl β-azidoacrylate reacts with substituted cinnamyl aldehydes to give a mixture of 2-arylpyridine and 4-styryldihydropyridine derivatives, whereas the reaction with substituted benzaldehydes provides 4-aryldihydropyridine derivatives. However, the iminophosphorane 16 derived from the diethyl azidofumarate reacts with cinnamyl aldehydes through the expected aza-Wittig fashion to give 4-arylpyridine derivatives after dehydrogenation of the resulting dihydropyridine.
- Molina, Pedro,Pastor, Aurelia,Vilaplana, Maria Jesus
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p. 8094 - 8098
(2007/10/03)
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- Synthetic Application of Vinyliminophosphoranes Based on the Reactivity of the Vinyl Side Chain. Preparation of Dihydropyridines
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New reactions of vinyliminophosphoranes with aldehydes involving an initial nucleophilic attack of the β-carbon atom of the vinyl side chain on the carbonylic carbon atom is reported.The resulting betaines undergo either intra- or intermolecular cyclization to give pyridines or dihydropyridines.
- Molina, Pedro,Pastor, Aurelia,Vilaplana, Maria Jesus
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p. 8283 - 8286
(2007/10/02)
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