Hetero-Aromatic Nitrogen Compounds

Schofield, K.

doi:10.1007/978-1-4899-5892-1

Cited by 134 publications

(82 citation statements)

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“…The conversions are lower confirming a strong influence of steric and electronic factors, as reported by FishÕs studies [12][13][14][15]. 1 In conclusion, the three complexes (1)- (3) are catalytically active in the hydrogenation of nitrogen containing heterocycles giving results comparable with those reported in the literature for other ruthenium systems like RuCl 2 (CO) 2 (PPh 3 ) 2 and Ru 4 H 4 (CO) 12 , but operating under milder reaction temperatures (353-373 K against 453 K) and lower catalyst/substrate ratio (1/100 against 1/10) [15].…”

Section: Resultssupporting

confidence: 69%

“…The RuH 2 (PPh 3 ) 4 (3) presents a greater catalytic activity with respect to (1) and (2): just after 3 h the conversion in the presence of (3) is 54.4% (entry 11), while it is 5.4% in the presence of (1) (entry 1) and 7.5% in the presence of (2) (entry 6). After a reaction time of 24 h, the conversion rises up to 86.7% in the presence of (3) (entry 14).…”

Section: Reaction Timementioning

confidence: 99%

“…Kinetic analysis of the data reported in Table 1 (entries [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17], following the procedure reported by Frediani et al [8], shows a first partial order with respect to reaction time with all the catalysts tested. The kinetic rates (K c ) are in the following order: (3) ) (2) @ (1) (14.60, 6.37 and 6.36 · 10 À6 s À1 , respectively) ( Table 2).…”

Section: Reaction Timementioning

confidence: 99%

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Catalytic activity of dihydride ruthenium complexes in the hydrogenation of nitrogen containing heterocycles

Frediani

Pistolesi

Frediani

et al. 2006

Inorganica Chimica Acta

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The catalytic activity of the dihydride ruthenium complexes, RuH 2 (CO) 2 (P n Bu 3 ) 2 , RuH 2 (CO) 2 (PPh 3 ) 2 and RuH 2 (PPh 3 ) 4 , in the hydrogenation of nitrogen containing heterocycles has been tested by analyzing the influence of reaction parameters such as temperature, hydrogen pressure, catalyst concentration, on the rate and regioselectivity of the reaction.RuH 2 (PPh 3 ) 4 shows a better catalytic activity with an 86.7% conversion of quinoline after 24 h at 100°C under a hydrogen pressure of 25 bar, while RuH 2 (CO) 2 (PPh 3 ) 2 and RuH 2 (CO) 2 (P n Bu 3 ) 2 in the same conditions give a conversion of 37.1% and 35.6%, respectively. These results are confirmed by the reaction rate of the hydrogenation of quinoline, since the K c in the presence of RuH 2 (PPh 3 ) 4 (1.46 · 10 À5 s À1 ) is higher than others (6.37 · 10 À6 s À1 for RuH 2 (CO) 2 (PPh 3 ) 2 and 6.36 · 10 À6 s À1 for RuH 2 (CO) 2 (P n Bu 3 ) 2 ).Noteworthy is the selectivity of these catalytic systems in the hydrogenation of quinoline: in all tests the three catalysts lead to 1,2,3,4-tetrahydroquinoline as the major product, furthermore this compound is the only formed in the presence of RuH 2 (CO) 2 (PPh 3 ) 2 . The selectivity is affected by the presence of an acid (CH 3 COOH) or a base (N n Bu 3 ) in the reaction media.The complex RuH 2 (PPh 3 ) 4 is catalytically active, even if in a minor extent, in the hydrogenation of isoquinoline, pyridine and 2-methylpyridine.The basicity of the substrate and steric hindrance around the nitrogen atom show a great influence on the conversion. The results obtained suggest that the catalytic system activates a heterocyclic ring through the coordination of the heteroatom to the metal centre of the complexes.

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Section: Resultssupporting

confidence: 69%

Section: Reaction Timementioning

confidence: 99%

Section: Reaction Timementioning

confidence: 99%

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Catalytic activity of dihydride ruthenium complexes in the hydrogenation of nitrogen containing heterocycles

Frediani

Pistolesi

Frediani

et al. 2006

Inorganica Chimica Acta

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“…It is known that pyrrole units in polypyrrole (PPy) are linked through their a-carbons [3]. As such, when the reaction mixture is subjected to oxidizing polymerization, the bare pyrrole molecules would polymerize first to form PPy nuclei and the growth of the nuclei would be terminated upon the participation of the a-substituted pyrrole molecules i.…”

Section: Discussionmentioning

confidence: 99%

Nanoparticles of Polypyrrole and Their Effect on Mediating Li Ion Transport from Liquid Electrolyte to Cathode

2001

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ABSCTRACT Nano-scale particles of polypyrrole (PPy) have been synthesized by polymerizing the respect monomer in the presence of its substituted homologue with oxyethylene (POE) oligomers as the substitute groups. The polymerization was carried out by introducing an aqueous solution of oxidant into the tetrahydrofurane (THF) solution of the monomers. The particles obtained possess brush-like architectures in the dispersing medium, and their sizes in dry state fall into the range of 10 to 40 nm according to TEM analysis. When dispersed by a low content (< 0.1 wt %) in an aprotic organic solvent, the nanoparticles synthesized have been found to affect the conduction of lithium ion. The effect is interpreted as a significant reduction in the electrical resistance at the electrode/electrolyte interface according to gain-phase impedance measurement. This has been attributed to the mediating role of the graft POE chains on the colloidal particles.

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“…Nauclefine (11), was isolated in 1975 first by Pousset as a minor indole alkaloid from Nauclea latifolia [10] and later as a major alkaloid by Sainsbury from Nauclea parva [11]. The extract of one such plant N. parva Merrill showed activity against the experimental P. 388 lymphocytic leukaemia in mice [12], Considerable interest has therefore developed in the synthesis of this alkaloid [13][14][15][16][17][18][19][20][21],…”

mentioning

confidence: 99%