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The Kröhnke method is featured in a solvent-free synthesis of triarylpyridines that proceeds via a homo-coupling of two diaryl substituted α, β-unsaturated carbonyl compounds. [12] This strategy offers a facile means for preparation of pyridnyl aryl systems that are important fragments of many useful drug scaffolds. Figure 7
The Chichibabin pyridine synthesis (/ ˈ tʃ iː tʃ iː ˌ b eɪ b iː n /) is a method for synthesizing pyridine rings. The reaction involves the condensation reaction of aldehydes, ketones, α,β-Unsaturated carbonyl compounds, or any combination of the above, with ammonia. [1] It was reported by Aleksei Chichibabin in 1924.
Pyridine is a basic heterocyclic organic compound with the chemical formula C 5 H 5 N. It is structurally related to benzene, with one methine group (=CH−) replaced by a nitrogen atom (=N−). It is a highly flammable, weakly alkaline, water-miscible liquid with a distinctive, unpleasant fish
Preparation [ edit ] 3-Aminopyridine is prepared by heating nicotinamide with sodium hypobromite ( Hofmann rearrangement ), which is in turn prepared in situ by the reaction of sodium hydroxide and bromine at 70 °C.
Dissolving Knorr's pyrrole in concentrated sulfuric acid, and then pouring the resulting solution into water will hydrolyze the 4-ester group selectively. The 5-methyl group can be variously oxidized to chloromethyl, aldehyde, or carboxylic acid functionality by the use of stoichiometric sulfuryl chloride in glacial acetic acid. [ 7 ]
Upon metabolism, 1,4-DHP based antihypertensive drugs undergo oxidation by way of cytochrome P-450 in the liver and are thus converted to their pyridine derivatives. [11] As a result, particular attention has been paid to the aromatization of 1,4-DHPs as a means to understand biological systems and so as to develop new methods of accessing ...
PDTC can be synthesized in the laboratory by treating the diacid dichloride of pyridine-2,6-dicarboxylic with H 2 S in pyridine: NC 5 H 3 (COCl) 2 + 2 H 2 S + 2 C 5 H 5 N → [C 5 H 5 NH +][HNC 5 H 3 (COS) − 2] + [C 5 H 5 NH]Cl. This route produces the pyridinium salt of pyridinium-2,6-dicarbothioate.
2,6-Di-tert-butylpyridine is prepared by the reaction of tert-butyllithium with pyridine. [2] The synthesis is reminiscent of the Chichibabin reaction . Some related bulky pyridine compounds have been described, including 2,4,6-tri-t-butylpyridine [ 3 ] and 2,6-di-tert-butyl-4-methylpyridine.