Tris pyridine

NOhOs,C,H3, Osmium, (acetonitrile)unde-cacarbonyltri-, 26 290 NO Os,ClsHj, Osmium, undecacarbonyl-(pyridine)tri-, 26 291 NiBCIFjIrPjCjoHji, Iridium(III), chloro-(dinitrogen)hydrido(tetrafluoro-borato(l - )]bis(triphenylphosphine)-, 26 119... 

Cyclooctadiene) (pyridine) (tri-cyclohexylphosphine)iridium(I) hexa-fluorophosphate, 88 Palladium catalysts, 230 Potassium-Graphite, 252 Sodium borohydride-Molybdenum(VI) oxide, 279... 

Regioselective lithiation.1 This complex undergoes selective lithiation at the orf/io-position, which can be trapped by methylation to give (2-methylpyridine)tri-carbonylchromium. The disilyl complex 2 undergoes selective lithiation at C4 because of steric effects. Reduction (DIBAH) of 1 provides (l,2-dihydro-pyridine)tri-carbonylchromium (3) after quenching (MeOH). Reaction of 1 with RLi followed by alkylation with CH3I provides the complex 4. 

The water-soluble fraction (from the original extraction of the reaction mixture described above) is evaporated to dryness, dissolved in 2 ml water, and applied to a Dowex AG 50 W x 8 column (H form, 200-400 mesh-column size, 0.6 x 5 cm). Water is used as the eluant, and the P-containing components are collected. The latter could be evaporated to dryness and silylated using the reagent pyridine/Tri-Sil TBT and BSTFA (1 2 2, v/v) (Pierce Chemical Co., Rockford, 1L). Subsequently an aliquot of this TMS derivative can be analyzed directly by the gas-liquid chromatography technique of Karlsson (1970). For further information on the detection and assay of choline and phosphocholine, suggested reading is an article by Kennedy (1991). 

O11NOS3C13H3, Osmium, (acetonitrile)un-decacarbonyltri-, 26 290 0 ]N0s3C (H5, Osmium, undecacar-bonyl(pyridine)tri-, 26 291 O11PRU3C19H11, Ruthenium, undecacar-bonyl(dimethylphenylphosphine)tri-, 26 273... 

Dipicolinicacid,H20/1 -(2-pyridylazo-)-2-naphthol,pyridine/ Tris(3,5-diisopropyl-pyrazol-l-yl)borate, h2o 3,1 22 152-154... 

Other direct one-pot syntheses are known and have been cited in the literature but are not practiced commercially. One example involves the formation of a diacid containing internal di-imide groups from the reaction of TMA and a diamine. The amide bond is then condensed in a second step in the same pot with additional diamine, using pyridine, tri-phenylphosphite, and lithium chloride in NMP [14]. This amide condensation may also be completed by the addition of a thionyl chloride/NMP complex to the diacid in the presence of an acid acceptor [15]. 

An interesting case of partial esterification is the acylation of Z-quinic acid. If the acid and acetic anhydride are refluxed briefly, one obtains tri-O-acetylquinide (the lactone of quinic acid). If zinc chloride is present, tetra-O-acetylquinic acid is formed 114)- However, if quinic acid and benzoyl chloride are heated at 130 to 140°, the main product is tetra-O-ben-zoylquinic acid. If the reaction is carried out in the presence of pyridine, tri-O-benzoylquinide is the chief product 116). 

Chloro-l-methylpyridinium iodide (1) reacts with a mixture of a carboxylic acid and an alcohol, in the presence of two equivalents of base, to form an ester (eq 1). The pyridinium salt (2) is formed rapidly by displacement of chloride from (1) by the carboxylate subsequent reaction with the alcohol results in formation of the ester, along with 1 -methyl-2-pyridone (3). A variety of solvents may be employed, but yields are highest in dichloromethane or pyridine. Tri-n-butylamine or Triethylanune are often used as base. The co-product (3) is insoluble in dichloromethane and so precipitates from this solvent. Good results are obtained even for hindered carboxylic acids and alcohols. 

Py complex [33134-16-6]. (Pyridine)tris(2,2,6,6-tetramethyl-3,5-heptanedionato-0,0 )gadolinium(lll)... 

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