2,2 ’-Bipyridine, reagent

Bipyridine — Iron(III) Chloride Reagent (Emmerie-Engel Reagent) 217... 

Note The dipping reagent, which can also be applied as a spray reagent, can be employed on cellulose and silica gel layers. A 3% solution of 2,2 -bipyridine in 40% thioglycolic acid can be employed as a specific spray reagent for the detection of iron (red coloration) [7],... 

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. 

Tris(2,2 -bipyridine)iron(3+) ion, 14 549 Tris(2,2 -bipyridine)iron(2+) ion, 14 549 Tris(2,2 -bipyridyl)ruthenium(II) complex chemiluminescence reagent, 5 856-857 Tris(2,3-dibromopropyl) phosphate, 11 502 Tris(2,3-dihydroxypropyl)isocyanurate, 8 204... 

The ability to conduct radical reactions without the use of tin reagents is important. Allylic triflones have been used to conduct allylation reactions on a range of substrates (39) as a replacement for allyltributylstannane (Scheme 28). The main limitation was that unactivated or trisubstituted triflones failed to undergo reactions. In other nontin radical methods, arenesulfonyl halides have been used as functional initiators in the CuCl/4,4 -dinonyl-2, 2 -bipyridine-catalysed living atom-transfer polymerization of styrenes, methacrylates, and acrylates.The kinetics of initiation and propagation were examined with a range of substituted arylsulfonyl halides with initiator efficiency measured at 100%. 

Automated parallel experiments were carried out to rapidly screen and optimize the reaction conditions for ATRP of methyl methacrylate (MMA) [34]. A set of 108 different reactions was designed for this purpose. Different initiators and different metal salts have been used, namely ethyl-2-bromo-tTo-butyrate (EBIB), methyl bromo propionate (MBP), (1-bromo ethyl) benzene (BEB), and p-toluene sulfonyl chloride (TsCl), and CuBr, CuCl, CuSCN, FeBr2, and FeCl2, respectively. 2,2 -Bipyridine and its derivatives were used as ligands. The overall reaction scheme and the structure of the used reagents are shown in Scheme 2. 

Several lithium reagents have been found to convert pyridine to 2,2 -bipyr-idines in satisfactory yield. Following from the formation of 2,2 -bipyridines from 2-lithiopyridines, it has been found that 2-benzyl-2-lithio-1,3-dithiane forms 2,2 -bipyridine in 30-75% yield when refluxed with pyridine in tetrahydrofuran, " and related compounds behave similarly. Lithium diisopropylamide with pyridine in ether affords up to 50% 2,2 -... 

Reagents (a) (CHaOln, HBr, HOAc (b)4,4 -bipyridine, CH3CN (c) 1,3-bis(bromomethyl)benzene, aq. CH3NO2... 

In early 1990 we began to work on catalyzed carboligations using organozinc reagents [1]. The reactions commonly involved diethylzinc 2, which was added enantioselectively to aldehydes 1 affording secondary alcohols 3. Initially, bipyridine 4 [2-6], pyridine 5 [3], and sulfoximines 6 [7] were applied as catalysts, which in some cases led to enantioselectivities greater than 95% ee [8, 9]. 

The direct electrochemical synthesis (Scheme 2) of the addncts of organomagnesinm halides with 2,2 -bipyridine (6) and salts of organodihalogenomagnesinm(II) anions (7) was reported by Hayes and coworkers . Adducts of different stoichiometry and 7 were obtained in the electrochemical oxidation of magnesium in ACN solutions containing organic halides RX (8), a.ro-dihalides XR X (9) and 8 with ammonium salts R NX, respectively. All new products showed none of the typical reactions of Grignard reagents. 

It has already been known for a long time that haloalkylzinc compounds are excellent reagents in cyclopropanation reactions . Such compounds, however, are rather unstable and are usually prepared in situ. It appears that 2,2 -bipyridine and 2,2 -biquinoline stabilize these haloalkylzinc compounds to a large extent . Compounds 110 and 111 (Table 6) are examples of stabilized cyclopropanating reagents that can be stored as solid materials over a longer period of time. 

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