4-hydroxyphenyl pyridine

The introduction of polar-pyiidine moieties was achieved by the use of the appropriate monomer diol and more specifically 2,5-bis(4-hydroxyphenyl) pyridine, which combines the rigid oligo-phenyl main chain strucmre with the presence of polar pyridine groups. The monomer can be prepared using palladium-mediated cross coupling of 2,5- dibromopyridine with a properly protected boronic acid. ... 

Scheme 5.1 Reaction sequences employed for the prep- bis(4-fluorophenyl)phenylphosphine oxide producmg aration of 2,5-bis(4-hydroxyphenyl)pyridine and 2,6-bis Homopolymers I and II, respectively. Reproduced fiom (4-hydroxyphenyl)pyridine and their polymerization with [7] with permission of the American Chemical Sodely...

As was expected the homopolymer composed from the 2,5-bis(4-hydroxyphenyl) pyridine and... 

As mentirmed before, another approach to improve solubility is the use of different n(Mi-substituted monomers that are randomly co-polymerized. Thus, non-substituted aromatic copolyethers containing main chain pyridine units were also synthesized by copolymerization of aromatic diphenols [11] and more particularly 2,5-bis(4-hydroxyphenyl) pyridine and 4,4 -biphenol or hydroquinone. Copolymer HI and rV, respectively. Using the previously... 

Beryllium chelates such as bis[2-(2-hydroxyphenyl)-pyridine]beryllium (Beq2, 86) (Scheme 3.74) emit pure blue light with an emission peak centered at 465 nm [269]. ITO/NPD/Bepp2/LiF/Al exhibited a maximum luminance of 15,000 cd/m2 and amaximum luminescent efficiency of 3.43 lm/W (3.8 cd/A). The emission color may have contributions from both NPD and Bepp2 as stated by the authors. 

Y. Liu, J. Guo, J. Feng, H. Zhang, Y. Li, and Y. Wang, High-performance blue electroluminescent devices based on hydroxyphenyl-pyridine beryllium complex, Appl. Phys. Lett., 78 2300-2302 (2001). 

Most complexes with catalytic properties are tetradentate derivatives of salen but other ligands, e.g., A-(hydroxyphenyl)salicyldimine and A-(hydroxyphenyl)pyridine-2-carboxaldimine, form ternary complexes with bipy and CU ((14) and (15), respectively) that are catalytically competent. 

Ru(H20)(bpy)(app)]Clj (H3app=A-(hydroxyphenyl)pyridine-2-carboxaldimine) is made by reaction of RuClj with 2-aminophenol and 2-pyridine carboxaldehyde under reflux followed by addition of (bpy). Infrared and electronic spectra were measured, and the room-temperature magnetic moment is 1.98 B.M. The system [Ru(H30)(bpy) (app)] +/TBHP/(BTBAC)/CH3Clj (BTBAC=benzyltributylammonium chloride) oxidised benzyl alcohol to benzaldehde and alkenes to mixtures (e. g. cis- and trans-stilbene to benzaldehyde and cis- and tranx-stilbene oxides). Alkanes gave mixtures... 

Azide ion will catalyze rearrangements of N- (aryloxy)pyridinium salts to give 3-(o-hydroxyphenyl)pyridines (Scheme 114). It is suggested that azide addition to the a-position... 

Mixed hydroxyphenyl-pyridine tripods (120) are also known.1 9 They act as anionic, tetradentate, N30-tripod ligands, ensuring fivefold coordination in their zinc complexes.189... 

The tautomeric equilibrium in 2-(2-hydroxyphenyl)pyridines 117 (R1 = H), except for 117 (R1 = H R2 = R3 = N02), is shifted completely toward the aromatic form 117a in chloroform, ethanol, DMF, and DMSO solution. A significant amount of the quinoid form 117b, however, was observed for 117 (R1 = H R2 = R3 = N02) in chloroform the molar fraction of 117b increases on addition of more polar acetonitrile (90KG75). 

It was noted that the 2-(2-hydroxyphenyl)pyridine N-oxide and its methyl ether, like orellanine itself and its tetramethyl ethers (295,296,298,314), are more prone to undergo loss not only of the oxygen atom but also of the hydroxyl or methoxy group, respectively, at the begining of MS fragmentation with the formation of an isoxazolinium-type cation. This would confirm the assumption (315) that the deoxidation mechanism also involves the process shown for the model compound in Scheme 55. 

Cu(BHPPDAH) H20-catalyzed one-pot synthesis of benzimidazoles was first reported by Sharghi et al. (2008). The catalyst was prepared from Cu(OAc)2 and A/,A-bis(2-hydroxyphenyl)-pyridine-2,6-dicarboxamide (BHPPDAH) (Scheme 4.43). Facilitated by the recyclable Cu(II) complex, various o-phenylenediamines smoothly cyclized with aromatic aldehydes to give benzimidazoles at room temperature under air atmosphere (Scheme 4.44). 

Hydroxypyridine 1-oxide 2-(2-Hydroxyphenyl)pyridine Phenyl(2-pyridyl)methanol 2-(l-Hydroxyethyl)pyridine... 

Addition of Arynes. Arynes generated from the decomposition of ortAo-trimethylsilylaryl triflates upon treatment with CsF have been reacted with the title compound to give 3-(2-hydroxyphenyl)pyridine in very good yields. The reaction is mostly selective, although the introduction of hindrance or... 

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