Chloro-4-Trimethylsilyl-Pyridine

The inductive electron-withdrawal of chlorine in 3-chloropyridine causes an increase in the acidities of the hydrogen atoms in the 2- and 4-positions. It is difficult to predict which proton will be preferentially abstracted by a given base. The 

If the same experiment is carried out in a THF-hexane mixture, the product obtained by distillation (low yield) consists predominantly of 3-chloro-4-methyl-thiopyridine. 

Stirring should be carried out at a moderate rate to prevent splashing of the reaction mixture into the relatively warm upper part of the flask, where decomposition can occur (brown colour). 

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Trimethylsilyl)pyridine-l-oxide and phosphorus oxyehloride give 2- and 4-chloro-3-(tiimethylsilyl)pyiidine, which are difficult to separate but which... 

Chloro-3-triinethylsilylpyri-dine, from 3-trimethylsilyl-pyridine-l-oxide, 122 hydrolysis, 122... 

Subsequent to the 1982 compilation of Lounila and Jokisaari [237], a large number of studies report chemical shift anisotropies for various nuclei in liquid crystalline solvents. Representative examples include ACTh in dichloromethylphosphine [243], methylisothiocyanide [244], and norborna-diene [141] A(Tc in chloro- and bromoform [245], bis(trimethylsilyl)diacetylene [246], and pyridine, pyrazine, pyridazine, and pyrimidine [247] ACTh and ACq in butyne [248], fluoro- [245,249], bromo- [245], and iodomethane [244, 245, 250], ethylene [251], methylisocyanide [252], dimethyl-mercury [253], benzene [250, 254, 255], 1,3,5-trichloro- [99, 256], 1,3,5-tribromo-[244], and 1,3,5-trinitrobenzene [244] Afluoro-methane [249] Aa in dimethylmercury [253] AcTsein carbon diselenide [258] AcTje in tellurophene [259] and AOxe [260]. 

Functionally substituted (77 -cyclopentadienyl)dicarbonyl iridium compounds were prepared from reactions of the corresponding substituted cyclopentadienyl-Na, -Li, or -T1 reagents with chlorodicarbonyl(pyridine)iridium. Ring-substituted compounds include chloro, benzyl, acetyl, carbomethoxy, methyl, benzoyl, trimethylsilyl, cyano, dimethylamino, tetra-Ph, dimethylaminoethyl, (tetramethyl)dimethylaminoethyl, methoxyethyl, pcntabenzyl, and pentamethyl. The symmmetric and antisymmetric carbonyl stretching frequencies as well as the NMR chemical shifts of the carbonyl substituents were correlated with various Hammett substituent parameters. ... 

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