Metalation, directed, of pyridines, quinolines

Mass spectral techniques in heterocyclic chemistry applications and stereochemical considerations in carbohydrates and other oxygen heterocycles, 42, 335 Mass spectrometry of heterocyclic compunds, 7, 301 of nucleic acids, 39, 79 Medium-large and large 7r-excessive heteroannulenes, 23, 55 Meso-ionic compounds, 19, 1 Metal catalysts, action on pyridines, 2, 179 Metalation, directed, of pyridines, quinolines, and diazines, 52, 187... 

Queguiner, G., Marsais, F., Snieckus, V., Epsztajn, J., Directed Metalation of n-Deficient Azaaromatics Strategies of Functionalization of Pyridines, Quinolines, and Diazines, 52, 187. 

Directed metalation of -deficient azaaromatics strategies of functionalization of pyridines, quinolines, and diazines, 52, 187 gem-Dithienylalkanes and their derivatives, 32, 83... 

Directed metallation of pyridines, quinolines, and diazines 91AHC (52)187. 

Mongin, F., Queguiner, G. Advances in the directed metallation of azines and diazines (pyridines, pyrimidines, pyrazines, pyridazines, quinolines, benzodiazines and carbolines). Part 1 Metallation of pyridines, quinolines and carbolines. Tetrahedron 2001, 57,4059-4090. 

Heteroatom-facilitated lithiations , Gschwend, H. W. and Rodriguez, H. R., Org. React., 1979, 26, 1 Directed metallation of 7r-deficient azaaromatics strategies of functionalisation of pyridines, quinolines, and diazines , Queguiner, G., Marsais, F., Snieckus, V., and Epsztajn, J., Adv. Heterocycl. Chem., 1991, 52, 187 Metallation and metal-assisted bond formation in 7r-electron deficient heterocycles , Undheim, K. and Benneche, T., Heterocycles, 1990, 30, 1155 Directed ortho metallation. Tertiary amide and O-carbamate directors in synthetic strategies for polysubstituted aromatics , Snieckus, V., Chem. Rev., 1990, 90, 879. 

High-valency metal fluoride fluorination of pyridine [82JFC(21)171], quinoline [82JFC(21)413], and 2-methylfurans [91 JFC(51)179] has been reported. With 2-methylfuran a complex mixture of stereoisomers of partially fluorinated oxolans was obtained. These can be dehydrofluorinated to fluorooxolens and no furans have been observed. Conformation and structural group were found to influence the direction and readiness toward dehydrofluorination [91 JFC(52) 165]. 

The direct introduction of an acetylide moiety, using pyridine A-oxide (or quinoline, diazine and triazine iV-oxides) can be achieved in a comparable way, by reaction with potassium phenylacetylide reaction with the lithium salt requires addition of acetyl chloride at the end of the reaction to aromatise. At low temperature, and using i-PrMgCl, 2-metallation of pyridine iV-oxides can be achieved, and thus, the introduction of electrophiles at the 2-position. ... 

In a series of interesting investigations, Suggs and Jun [152] have shown ready C-C cleavage by directed attack in quinoline-derived ketones where the metal binds in such a way as to bring it into close proximity with the bond to be cleaved (Eq. 2.60 R = CH2Ph, Et py = pyridine). Addition of PPha causes reductive elimination back to the starting ketone. Intermolecular versions of this reaction were also observed [153]. 

In contrast, nitrogen-containing bases are contained in many crude-oil fractions. In a typical starting material, 25 35 % of the nitrogen compounds have basic character. The sensitivity of solid acids towards these poisons correlates directly with their basicity. For example, pyridine, quinoline, amines, and indoles are basic, while pyrrole and carbazole are nonbasic. These poisons are best removed by hydrogenation, together with sulfur and most of the heavy metal poisons. 

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