2,2 -Bipyridines, synthesis

Cinellu, M.A., Minghetti, G., Pinna, M.V., Stoccoro, S., Zucca, A., Manassero, M. and Sansoni, M. (1998) X-Oxo and alkoxo complexes of gold(III) with 6-alkyl-2,2 -bipyridines. Synthesis, characterization and X-ray structures. Journal of the Chemical Society,... 

Bipyranylidene, 2,2, 6,6 -tetraphenyl-, formation, 60, 156 Bipyridines, synthesis by catalytic... 

FUNCTIONALIZED BIPYRIDINES SYNTHESIS AND USES OF COMMON BUILDING BLOCKS 6... 

A variation by Potts utilizes a-oxoketene ditioacetals in a condensation-cyclization bipyridine synthesis.49,50 For example, reaction of the Q-oxoketenc dithioacetal 3,3-bis(methylthio)-l-(2-pyridinyl)-2-propen-l-one with acetone and potassium /-butoxide, followed by treatment of the intermediate 1,5-enedione potassium salt, (9), with ammonium acetate produced the unsymmetric 6-methyl-4-(methylthio)-bpy, (10) (Scheme 5). Desulfurization with nickel boride afforded 6-methyl bipyridine in 72% yield. Various substituted bpys with alkyl and alkylsulfonyl groups were similarly produced in yields ranging from 37% to 94%. 

Maggini M, Done A, Scorrano G and Prato M 1995 Synthesis of a [60]fullerene derivative covalently linked to a ruthenium (II) tris(bipyridine) complex J. Chem. Soc., Chem. Commun. 845-6... 

Chiral carbenoid complexes with 2,2 -bipyridine ligands for asymmetric synthesis 98YGK764. 

Reaction of -picoline over degassed Raney nickel was found to give 5,5 -dimethyl-2,2 -bipyridine (5), the structure of which was established by its synthesis from 2-bromo-5-methylpyridine. Oxidation of this dimethyl-2,2 -bipyridine, and similar oxidation of the diethyl-2,2 -bipyridine derived from 3-ethylpyridinc, gave the corresponding dicarboxylic acid and the same acid was produced by the action of degassed Raney nickel on sodium nicotinate (in water) or on ethyl nicotinate. These transformations established the 5,5 -substitution pattern for three 2,2 -bipyridines derived from 3-substituted pyridines but such evidence is not available for the biaryls... 

In their search for new hgands with a very high binding affinity for the nicotinic acetylchohne receptor (nAChR), potentially useful in positron emission tomography (PET) when radiolabeled with [ F], Horti et al. described the synthesis of BOC-protected 5-(azetidin-2-ylmethoxy)-2-chloro-6 -fluoro-3,3 -bipyridine via a sequential classical heating and microwave irradiation of (2-fluoro-5-pyridinyl)(trimethyl)stannane with f-butyl 2- [(6-chloro-5-... 

Homolytic aromatic substitution often requires high temperatures, high concentrations of initiator, long reaction times and typically occurs in moderate yields.Such reactions are often conducted under reducing conditions with (TMSlsSiH, even though the reactions are not reductions and often finish with oxidative rearomatization. Reaction (68) shows an example where a solution containing silane (2 equiv) and AIBN (2 equiv) is slowly added (8h) in heated pyridine containing 2-bromopyridine (1 equiv) The synthesis of 2,3 -bipyridine 75 presumably occurs via the formation of cyclohexadienyl radicals 74 and its rearomatization by disproportionation with the alkyl radical from AIBN. ... 

These authors further described the synthesis and resolution (by chiral HPLC) of a new C2-symmetric planar-chiral bipyridine ligand [43] (see structure 35 in Scheme 18). They obtained an X-ray crystal structure of the corresponding copper complex proving a bidentate complexation. This system led to high diastereo- (up to 94%) and enantioselectivity (up to 94%) in the... 

The synthetic route represents a classical ladder polymer synthesis a suitably substituted, open-chain precursor polymer is cyclized to a band structure in a polymer-analogous fashion. The first step here, formation of the polymeric, open-chain precursor structure, is AA-type coupling of a 2,5-dibromo-1,4-dibenzoyl-benzene derivative, by a Yamamoto-type aryl-aryl coupling. The reagent employed for dehalogenation, the nickel(0)/l,5-cyclooctadiene complex (Ni(COD)2), was used in stoichiometric amounts with co-reagents (2,2 -bipyridine and 1,5-cyclooctadiene), in dimethylacetamide or dimethylformamide as solvent. 

In 2008, Rykowski et al. reported the synthesis of optically active 2,2 -bipyridine alkyl sulfoxides by asymmetric oxidation of their corresponding readily accessible 2,2 -bipyridine alkyl sulfides. These sulfoxides were further evaluated as ligands for the enantioselective addition of ZnEt2 to benzaldehyde, providing only low enantioselectivities of up to 14% ee (Scheme 3.34). 

Detailed procedures for the synthesis of various often used [Ni°L4] complexes (L = phosphines, arsines, stibines, alkyl isocyanides) and [Ni°L 2] complexes (L = bipyridine, phenantroline, diphosphines, diarsines) have been compiled.2413... 

A tridentate SNO ligand coordinates with a bipyridine to give ((2,2 -bipyridine)[2-(2-mercapto-phenyl)iminophenoxy])zinc. The monomeric complex has a distorted trigonal bipyramidal geometry with a phenolate and a thiolate coordinated. The synthesis was carried out electrochemically from anodic zinc in the presence of a disulfide-linked ligand precursor.867... 

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