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The Kröhnke method in this synthesis was crucial due to the failure of other cyclization techniques such as the Glaser coupling or Ullmann coupling. Figure 13. Another use of the Kröhnke pyridine synthesis was the generation of a number of 2,4,6-trisubstituted pyridines that were investigated as potential topoisomerase 1 inhibitors.
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 ...
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.
Using secondary amines (as opposed to primary amines) the Zincke reaction takes on a different shape forming Zincke aldehydes in which the pyridine ring is ring-opened with the terminal iminium group hydrolyzed to an aldehyde. The use of the dinitrophenyl group for pyridine activation was first reported by Theodor Zincke.
2-Picoline was the first pyridine compound reported to be isolated in pure form. It was isolated from coal tar in 1846 by T. Anderson. [2] This chemistry was practiced by Reilly Industries. [3] It is now mainly produced by two principal routes. One method involves the condensation of acetaldehyde and ammonia in the presence of an oxide catalyst ...
This yellow crystalline solid is a derivative of pyridine. The compound and its derivatives serve primarily as acylating agents. A few of 2-mercaptopyridine's other uses include serving as a protecting group for amines and imides as well as forming a selective reducing agent. 2-Mercaptopyridine oxidizes to [[2,2 ′-dipyridyl disulfide]]. [1]
Benzyl groups can be removed by catalytic hydrogenolysis over palladium on carbon, and tertiary-butyl groups can be removed by treatment with trifluoroacetic acid, or boiling aqueous acetic acid. R 1 and R 3 (as well as R 2 and "Et") can be varied by the application of appropriate β-ketoesters readily made by a synthesis emanating from acid ...
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.