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4-Methylpyridine is the organic compound with the formula CH 3 C 5 H 4 N. It is one of the three isomers of methylpyridine. This pungent liquid is a building block for the synthesis of other heterocyclic compounds. Its conjugate acid, the 4-methylpyridinium ion, has a pK a of 5.98, about 0.7 units above that of pyridine itself. [1]
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 ]
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. [ 20 ] 2-acetylthiophene ( 46 ) was treated with iodine and pyridine to generate α-pyridinium acyl ketone 47 .
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. [ 4 ]
DNA is defined by containing 2'-deoxy-ribose nucleic acid while RNA is defined by containing ribose nucleic acid. [1] In some occasions, DNA and RNA may contain some minor bases. Methylated forms of the major bases are most common in DNA. In viral DNA, some bases may be hydroxymethylated or glucosylated.
3-Methylpyridine degrades more slowly than the other two isomers, likely due to the impact of resonance in the heterocyclic ring. Like most simple pyridine derivatives, the picolines contain more nitrogen than is needed for growth of microorganisms, and excess nitrogen is generally excreted to the environment as ammonium during the degradation ...
Pyridine N-oxide is five orders of magnitude less basic than pyridine: the pK a of protonated pyridine-N-oxide is 0.8. [7] Protonated derivatives are isolable, e.g., [C 5 H 5 NOH]Cl. [3]
A synthesis of 1,4-dihydropyridines in aqueous micelles catalyzed by PTSA under ultrasonic irradiation. Using condensation of benzaldehyde , ethyl acetoacetate and ammonium acetate as a model, experiments have proven that when catalyzed by p-toluenesulfonic acid (PTSA) under ultrasonic irradiation, the reaction can have a product yield of 96% ...