Search results
Results from the WOW.Com Content Network
The synthesis of tropinone can be seen as a variation of the Petrenko-Kritschenko reaction in which the two aldehyde functions are covalently linked in a single molecule. Apart from the Hantzsch synthesis the Petrenko-Kritschenko reaction is one of the few examples in which a symmetric pyridine precursor can be obtained in a multicomponent ring ...
The Kröhnke pyridine synthesis provides a fairly general method for generating substituted pyridines using pyridine itself as a reagent which does not become incorporated into the final product. The reaction of pyridine with bromomethyl ketones gives the related pyridinium salt, wherein the methylene group is highly acidic.
[1] [2] The initial reaction product is a dihydropyridine which can be oxidized in a subsequent step to a pyridine. [3] The driving force for this second reaction step is aromatization. This reaction was reported in 1881 by Arthur Rudolf Hantzsch. A 1,4-dihydropyridine dicarboxylate is also called a 1,4-DHP compound or a Hantzsch ester.
The reaction conditions for the Kröhnke synthesis are generally facile and the reactions often proceed in high yields with reaction temperatures generally not exceeding 140 °C. [6] The Kröhnke synthesis is generally performed in either glacial acetic acid or methanol, but it can also be done under aqueous conditions, and more recently under ...
Piperidine is also commonly used in chemical degradation reactions, such as the sequencing of DNA in the cleavage of particular modified nucleotides. Piperidine is also commonly used as a base for the deprotection of Fmoc-amino acids used in solid-phase peptide synthesis.
2-Phenylpyridine is an organic compound with the formula C 6 H 5 C 5 H 4 N (or C 11 H 9 N). It is a colourless viscous liquid. It is a colourless viscous liquid. The compound and related derivatives have attracted interest as precursors to highly fluorescent metal complexes of possible value as organic light emitting diodes (OLEDs).
Dimerization is a side reaction that can occur. When heated in xylene and sodium amide at atmospheric pressure, the substrate 4-tert-butylpyridine produces 89% of the dimer product (4,4'-di-tert-butyl-2,2'-bipyridine) and only 11% of the aminated Chichibabin product (2-amino-4-tert-butylpyridine). [3]
The reaction of 3-bromo-4-chloropyridine with furan and lithium amalgam gives 1,4-epoxy-dihydroquinoline through the 2,3-pyridyne intermediate. The reaction of 4-bromopyridine with sodium in liquid ammonia gives both 3-aminopyridine and 4-aminopyridine through the 3,4-pyridyne intermediate and an E1cB-elimination reaction. [2]