Methyl 2 pyridone

It is found in practice that for a number of compounds reacting ma the predominant species an almost horizontal plot is obtained. For compounds presumed to be nitrated via the free bases, such as 2,6-lutidine i-oxide and 3- and 5-methyl-2-pyridone, slopes of approximately unity are obtained. Since this type of plot allows for the incomplete ionisation of nitric acid, it can be used at higher acidities than plots using — ( H + logio Hjo) which break down when the condition is no longer true. 

The similarity of their rate profiles, and the similarity of their rate constants for nitration at a particular temperature and acidity show that 4-pyridone, i-methyl-4-pyridone, and 4-methoxypyridine are all nitrated as their cations down to about 85 % sulphuric acid. The same is true of 2-methoxy-3-methylpyridine. In contrast, 3- and 5-methyl-2-pyridone, i,5-dimethyl-2-pyridone and 3-nitro-4-pyridone all react... 

The N-oxide function has proved useful for the activation of the pyridine ring, directed toward both nucleophilic and electrophilic attack (see Amine oxides). However, pyridine N-oxides have not been used widely ia iadustrial practice, because reactions involving them almost iavariably produce at least some isomeric by-products, a dding to the cost of purification of the desired isomer. Frequently, attack takes place first at the O-substituent, with subsequent rearrangement iato the ring. For example, 3-picoline N-oxide [1003-73-2] (40) reacts with acetic anhydride to give a mixture of pyridone products ia equal amounts, 5-methyl-2-pyridone [1003-68-5] and 3-methyl-2-pyridone [1003-56-1] (11). 

By contrast, the rate-acidity profiles for nitration of 3-nitro-4-pyridone, 3-and 5-methyl-2-pyridone and l,5-dimethyl-2-pyridone resemble each other and differ from the above-indicated reaction upon the free base, and correction of the observed rates to allow for the concentration of free base actually present gave rate-acidity profiles of the expected form the corrected entropies of activation then turned out to be positive. Furthermore, if the logarithms of the corrected rate coefficients obtained in media of low acidity were plotted against +log aHlQ, then slopes of near unity were obtained (see above, p. 18), but not otherwise. A similar result was obtained from the nitration data for 4-pyridone in media of low acidity suggesting that here it reacts as the free base. A further test which was applied was to calculate the concentration of nitronium ions in the various media and to correct the observed rate coefficients for this the logarithms of these coeffi-... 

Examples of other organic materials prepared by mechanochemical procedures, for which stmcture determination has been carried out directly from powder XRD data, include a hydrate cocrystal of 5-methyl-2-pyridone and trimesic acid, which was prepared by grinding a methanol solvate cocrystal of the same components... 

Trimesic acid 5-Methyl-2-pyridone Structure of a new cocrystal product generated by solid-state grinding of the methanol solvate cocrystal [52]... 

Figure 2.2.7 Distance between 5-methyl-2-pyridone 66 a molecules in 74.

Studies with 3-substituted pyridines indicate that the product distribution depends on the substituent. When the group in the 3-position is methyl, the two isomeric 2-pyridones are formed in about equal amoxmts. However, when the group is inductively electron withdrawing, the 3-substituted-2-pyridone either predominates or is the only isolated product. 3-Picoline-l-oxide and acetic anhydride give 3-methyl-2-pyridone (35-40%), 5-methyl-2-pyridone (35-40%), and 3-methyl-l-(5-methyl-2-pyridyl)-2-pyridone (4%) after hydrolysis with water. In a later study, much less 3-methyl-2-pyridone was detected. ... 

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