Pyridine, 3,5-dimethyl-, palladium

C2H,N, Pyridine, 3,5-dimethyl-palladium complex, 26 210 CbHsNO, Benzoyl isocyanide chromium com-C HbO, Ethanone, 1-phenyl-manganese complex, 26 156-158 CBH, 02, Methyl benzoate chromium complex, 26 32 C H i, o-Xylylene magnesium complex, 26 147 ChH P, Phosphine, dimethylphenyl-iron complex, 26 61 ruthenium complex, 26 273 ChH12, 1,5-Cyclooctadiene iridium complex, 26 122 ruthenium complexes, 26 69-72, 253-256 ChH OjPS, 2-Butenedioic acid, 2-(dimethylphosphinothioyl)-dimethyl ester, manganese complex, 26 163... 

CjHgOjS, Benzenesulfonic acid, 4-methyl-, rhodium complex 27 292 C,H,N, Pyridine, 3,5-dimethyl-, palladium complex, 26 210... 

CO, and methanol react in the first step in the presence of cobalt carbonyl catalyst and pyridine [110-86-1] to produce methyl pentenoates. A similar second step, but at lower pressure and higher temperature with rhodium catalyst, produces dimethyl adipate [627-93-0]. This is then hydrolyzed to give adipic acid and methanol (135), which is recovered for recycle. Many variations to this basic process exist. Examples are ARCO s palladium/copper-catalyzed oxycarbonylation process (136—138), and Monsanto s palladium and quinone [106-51-4] process, which uses oxygen to reoxidize the by-product... 

Reaction of -picoline with a nickel-alumina catalyst has been reported to give a mixture of four isomeric dimethylbipyridines, one of which has been identified at 6,6 -dimethyl-2,2 -bipyridine. With palladium-on-carbon, 2,4-lutidine was found to be more reactive than pyridine,and the isolated biaryl has been assigned the structure (2). However, some confusion arises from the statement that this... 

Several products other than 2,2 -biaryls have been isolated following reaction of pyridines with metal catalysts. From the reaction of a-picoline with nickel-alumina, Willink and Wibaut isolated three dimethylbipyridines in addition to the 6,6 -dimethyl-2,2 -bipyridine but their structures have not been elucidated. From the reaction of quinaldine with palladium-on-carbon, Rapoport and his co-workers " obtained a by-product which they regarded as l,2-di(2-quinolyl)-ethane. From the reactions of pyridines and quinolines with degassed Raney nickel several different types of by-product have been identified. The structures and modes of formation of these compounds are of interest as they lead to a better insight into the processes occurring when pyridines interact with metal catalysts. 

The supported aqueous phase methodology was applied to the system Pd(OAc)2/5 TPPTS, a catalytic precursor for the Trost-Tsuji reaction. The characterization of the solid by 31P MAS NMR confirms the presence of Pd°(TPPTS)3 as the main surface species. The catalytic properties of the solid were tested for the allylic substitution of E-cinnamylethylcarbonate by different nucleophiles such as ethyl acetoacetate, dimethyl malonate, morpholine, phenol, and 2-mercapto-pyridine. The absence of palladium leaching was demonstrated, and having solved the problem of water leaching from the solid to the organic phase, the SAP-Pd catalyst was successfully recycled several times without loss in its activity. It was used in a continuous flow experiment which... 

Several of the methods of synthesis of 2,2 -bipyridines have their counterpart in the preparation of 4,4 -bipyridine. The Ullmann reaction has been used to prepare 4,4 -bipyridine. Thus 4-halogenated pyridines afford 4,4 -bipyridine. Dehalogenation and dimerization of 4-bromopyridine may be accomplished too with hydrazine and alkali at 65°C in the presence of a palladium catalyst, whereas 4-chloropyridine is converted to 4,4 -bipyridine in 46% yield by reaction with alkaline sodium formate in the presence of palladium on charcoal and a surfactant. Several extensions of the Ullmann reaction have recently been reported, especially for the synthesis of substituted 4,4 -bipyridines. Thus 4-iodo-2-methylpyridine gives 2,2 -dimethyl-4,4 -bipyridine, 3-nitro-4-chloropyridine affords 3,3 -dinitro-4,4 -bipyridine, 4-bromo- or 4-iodotetrafluoropyridine gives octafluoro-4,4 -bipyridine, and 4-iodo- or 4-bromotetrachloropyridine gives octachloro-4,4 -bipyridine. Related syntheses have been de-... 

Table 7 Asymmetric cyclization/hydrosilylation of dimethyl diallyl malonate catalyzed by palladium pyridine-oxazoline complexes...

NC12Hm, Pyridine, 2-(phenylmethyl)-palladium complex, 26 208-210 NCi2H,j, Naphthalenamine, /V.A -dimethyl-lithium complex, 26 154 NCi2Hv, Benzo[/i]quinoline ruthenium complex, 26 177 NCojCuO CuH, Ruthenium, (acetonitrile)-dodecacarbonyltricobaltcopper-, 26 359 NCo Oi RuC,2H2(1, Ruthenate(l-), dodeca-carbonyltricobalt-tetraethylammonium, 26 358 NCrFeOvP2C45Hji, Chromate(l-), hydri-dononacarbonyliron-(x-nitrido-bis( triphenylphosphorus)( 1 +), 26 338... 

Carboxylation of dienes and trienes, which takes place in a stepwise fashion, affords mono- or dicarboxylated products.146 Cobalt carbonyl,147 palladium chloride,148 149 and palladium complexes150 were used. 1,4 Addition to 1,3-butadiene gives the corresponding unsaturated tram ester (methyl trans-3-pentenoate) in the presence of [Co(CO)4]2 and a pyridine base.147 The second carboxylation step requires higher temperature than the first one to yield dimethyl adipate. In a direct synthesis (110°C, 500 atm, then 200°C, 530 atm) 51% selectivity was achieved.147... 

Heath and Rees corrected the earlier conclusions of Potts et al. (66JOC265) and Sai et al. [81IJC(B)10] who had reacted 1,2,4-triazolo[4,3-a]pyridine with dimethyl acetylenedicarboxylate in boiling toluene and benzene. The latter believed that 3-substituted triazolopyridines 209 and 210 were the products. Heath and Rees repeated the experiments in refluxing benzene and in refluxing toluene both in the presence and absence of 5% palladium-on-charcoal, and showed that under all sets of conditions 3-cyano-4-oxo-4f/-pyrido[l,2-a]pyrimidine-2-carboxylate 212, 5-(2-pyridyl)pyrazole-3,4-dicarboxylate 213, and an adduct 211 were isolated from the complex reaction mixtures in 20%, 20%, and 1% yields, respectively (82CC1280). When the reaction was carried out in methanol, only 3-cyano-4-oxo-4//-pyrido[ 1,2-a]pyrimidine-2-carboxylate 212 was obtained... 

C12H111N2, Azobenzene, cobalt and palladium complexes, 26 175, 176 manganese complex, 26 173 C12H11N, Pyridine, 2-(phenylmethyl)-, palladium complex, 26 208-210 C12H11P, Phosphine, diphenyl-, manganese complex, 26 158, 226-230 ruthenium complex, 26 264 Ci2H,20,S, Thiophenetetracarboxylic acid, tetramethyl ester, 26 166 C 2H,5N, Naphthalenamine, A ,iV-dimethyl-, lithium complex, 26 154 Cj2Hih, Benzene, hexamethyl-, ruthenium complex, 26 181, 182... 

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