N-methyl-2-pyridone

Bromopyridine has been made by direct bromination of pyridine - from N-methyl-2-pyridone with phosphorus penta-bromide and phosphorus oxybromide from 2-aminopyridine by diazotization with amyl nitrite in 20% hydrobromic acid from sodium 2-pyridinediazotate by solution in concentrated hydrobromic acid and from 2-aminopyridinc by diazotization in the presence of bromine and concentrated hydrobromic acidd The method described here is essentially that of Craig. 

R-methyl-2-pyridone- N-methyl-2-pyridone-3-carboxylic acid 3-carhoxylic acid amide... 

Grabowska et al [112] reported methylation of 2-hydroxypyridine with methanol over hydrothermally synthesized zinc aluminate spinels. N-methyl-2-pyridone was formed selectively (95%) and 100% 2-hydroxy pyridine conversion was achieved at 340°C. During the experiment the activity of the catalyst was shown to be stable and catalyst can be regenerated repeatedly without any significant loss of activity by passing air through the catalyst bed at 500°C. 

Several other heterocyclic compounds have been used in the vinyl substitution. Quinones, for example, are readily substituted with a variety of heterocycles as well as with benzene.7 Heterocycles which react include 2-acetylfuran (5-position), furfural (5-position) (equation 5) methyl furoate (5-position), 2-ace-tylthiophene (5-position), N-benzenesulfonylpyirole (2-position), N-benzenesulfonylindole (3-position), 4-pyrone (3-position) and N-methyl-2-pyridone (3- and 5-positions). 

A-Methylpyridinium or A-methylquinolinium salts [246] may be oxidized to the N-methyl-2-pyridone or A-methyl-2-quinolone, respectively, in alkaline medium containing some potassium hexacyanoferrate (III). The reaction is probably an indirect electrolysis in which the hexacyanoferrate oxidizes the pseudobase and is, in turn, reoxidized at the anode. 

Excess niacin is excreted mainly as the N-methylnico-tinamide (NMN), after methylation in the liver, and the two oxidation products of NMN, N-methyl-2-pyridone-5-carboxamide, and N-methyl-4-pyridone-carboxamide. ... 

At present, no blood markers are commonly used as indicators of niacin status. Most assessments of niacin nutriture have been based on measurement of the 2 urinary metabolites, N -methylnicotinamide and N -methyl-2-pyridone-5-carboxamide. Normally, adults excrete 20% to 30% of their niacin in the form of methylnicotinamide and 40% to 60% as the pyridone. An excretion ratio of pyridone to methylnicotinamide of 1.3 to 4.0 is thus normal, but latent niacin deficiency is indicated by a value below 1.0. As depletion occurs, the pyridone is absent for weeks before clinical signs are noted, and the methylnicotinamide excretion falls to a minimum at about the time that clinical signs are evident.f HPLC methods are currently the methods of choice, though some capillary electrophoresis methods have been developed. However, the measurement of 2-pyridone and N -methylnicotinamide concentrations in plasma may provide a more reliable metabolite ratio than urine measurements. A newer approach that may prove valuable is the ratio of NAD/NADP in erythrocytes and plasma tryptophan. A ratio of NAD/NADP below 1.0 would be indicative of a risk of developing niacin deficiency. ... 

In the more rigorous of the two approaches Beak el al.n determined calorimetrically AH° for the equilibrium between N-methyl-2-pyridone (la, R = Me) and 2-methoxypyridine (lb, R = Me) (A/fdeioo0) and also for that between the saturated analogs (4a, 4b, R = Me) (A ioc°). Equilibrations were performed using catalytic amounts of the appropriate... 

Of special interest are the photochemical intramolecular (2 + 2)-cycloadditions of 2-pyrones and 2-pyridones because the resulting 2-oxa- or 2-azabicyclo[2.2.0]hex-5-en-3-ones are precursors of cyclobutadiene and stable complexes of cyclobutadiene.12,238-261 In 1964 Corey and Streith238 reported the photochemical conversion of 2-pyrone (222) and N-methyl-2-pyridone (223) into the corresponding bicyclic isomers (224 and 225) at —20°. More recent studies performed at a temperature as low as 8°K with 2-pyrones in a matrix of argon or nitrogen showed that the intramolecular (2 + 2)-cycloaddition is only a minor photochemical pathway.12,260-262 The major reaction proved to be... 

The electron-transfer-sensitized coupling of 1,2-dimethylindole with N-methyl-2-pyridone is also thought to proceed via side-chain deprotonation of an indole radical cation, as shown in Scheme 54 [105]. 

V2. Vivian, V. M., Chaloupka, M. M., and Reynolds, M. S., Some aspects of tryptophan metabolism in human subjects. I. Nitrogen balances, blood pyridine nucleotides and urinary excretion of N-methyliiicotinamide and N-methyl-2-pyridone-5-carboxamide on a low-niacin diet. J. Nutr, 66, 587-598 (1958). 

Nicotinic acid and nicotinamide These are sometimes known by the generic term niacin. Their importance is in combination with tryptophan, as the coenzyme forms nicotinamide adenine dinucleotide (NAD + ) and nicotinamide adenine dinucleotide phosphate (NADP). HPLC is too insensitive to measure endogenous plasma levels, but the urinary metabolites N-methyl-2-pyridone-5-carboxylamide and N -methylnicotinamide can be measured to assess niacin status. Preliminary cleanup of urine by anion-exchange resins is followed by reversed-phase HPLC with UV detection. 

The status of niacin in relation to most other vitamins is different as it can be synthesized by humans to some extend from tryptophan. Body status determination has been based on the determination of urinary excretion of niacin metabolites, predominately N-methyl-2-pyridone-5-carboxylamide and N-methyl-nicotinamide. The ratio of these compounds has been used as indicator of niacin status. Recent studies suggest that the determination of the two niacin-derived coenzymes, NAD and NADP, in erythrocytes, and their ratio are more reliable indicators of niacin status. However, a broadly accepted and easy to use determination method does not seem to exist. 

The 2-cyano-N-methylpyridinium ion, the 2-carboxy-l-methylpyridinium ion and N-methyl-2-pyridone have been identified as metabolites of V-methylpyri-dinium-2-aldoxime iodide (2-PAM) (Xn-413) in rats. 

Although early attempts were unsuccessful, it is possible to reduce 7V-methyl-2-pyridones with lithimn aluminum hydride and aluminum chloride in tetrahydro-furan or ether, or without aluminum chloride in tetrahydrofuran. N-Methyl-2-pyridone (MI-640, R = H) gives l-methyl-3-piperideine (XII-641, R = H) as the major product and 1,4-dimethyl-2-pyridone (XD-640, R = CH3) gives... 

It has been suggested that deuteration of N-methyl-2-pyridone occurs at the methyl group.Base-catalyzed hydrogendeuterium exchange, however, takes place at the 2- and 6-positions of 4-pyridones (MI-686, R = H, CH3, Br) and 4-methoxy-l-methylpyridinium tetrafluoroborate (MI-687) and at the 6-posi-tion of Mmethyl-2-pyridone in deuterium oxide via an ylide mechanism. The rates of exchange relative to A-methyl-4-pyridone are ... 

Shibata, K., and Matsuo, H., 1989. Correlation between niacin equivalent intake and urinary excretion of its metabolites, N -methylnicotinamide, N -methyl-2-pyridone-5-carboxamide, and N -methyl-4-pyridone-3-carbox-amide, in humans consuming a self-selected food. The American Journal of Clinical Nutrition. 50 114-119. 

The stabilities of the C(6)-centred carbanions derived from 1,3-dimethyluracil, N-methyl-2-pyridone, and A-methyl-4-pyridone have been systematically investigated in the gas phase, DMSO (dimethyl sulfoxide) and in water solutions." The stabilities of the carbanions in the gas phase and DMSO were directly measured through their reactions with carbon acids with known proton affinity or pTTa values. The carbanions derived from the two pyridones were found to have the same stability, whereas the carbanion... 

C14H15I3N2O2, Benzamide - hydrogen triiodide, 29, 656 Ci4Hi9N30ft, N-Methyl-2-pyridone - 5,5-diethylbarbituric acid (1 1), 40B, 555... 

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