2-methyl-5-ethylpyridine

Although an inherently more efficient process, the direct chemical oxidation of 3-methylpyridine does not have the same commercial significance as the oxidation of 2-methyl-5-ethylpyridine. Liquid-phase oxidation procedures are typically used (5). A Japanese patent describes a procedure that uses no solvent and avoids the use of acetic acid (6). In this procedure, 3-methylpyridine is combined with cobalt acetate, manganese acetate and aqueous hydrobromic acid in an autoclave. The mixture is pressurized to 101.3 kPa (100 atm) with air and allowed to react at 210°C. At a 32% conversion of the picoline, 19% of the acid was obtained. Electrochemical methods have also been described (7). 

The second alkaloid solanocapsidine, C2gH4404N2, m.p. S05° (approx.), is amorphous. It was used for a selenium dehydrogenation experiment and yielded Diels s hydrocarbon, y-methylci/ciopentenophenanthrene (picrate, m.p. 117°) and a mixture of bases from which 2-methyl-5-ethylpyridine (picrate, m.p. 162°) and 4-methyl-2-ethylpyridine (picrate, m.p. 125°) were isolated. 

In a process developed by Hoffmann La Roche (Roessler, 1996) for the anti-Parkinsonian drug, lazabemide, palladium-catalysed amidocarbonylation of 2,5-dichloropyridine replaced an original synthesis that involved eight steps, starting from 2-methyl-5-ethylpyridine, and had an overall yield of 8%. The amidocarbonylation route affords lazabemide hydrochloride in 65% yield in one step, with 100% atom efficiency (Fig. 2.22). 

Nicotinic acid Nicotinic acid, pyridine-3-carboxylic acid (20.2.9) is synthesized industrially by heating a paraldehyde trimer of acetaldehyde, under pressure with ammonia, which leads to the formation of 2-methyl-5-ethylpyridine, followed by oxidation with nitric acid which gives the desired product [22-25]. 

There are now a reasonable number of reactions in which derivatives of pyrimidine are converted into pyridines. The tetrahydropyrimidine (792) is converted into a dihydropyridine by heating with silica and alumina (48HCA612). It was assumed that hydrolysis gave a ketoimine (also obtained directly from acetone and ammonia), which recydized. Pyrimidine itself is converted by hot (190 °C) aqueous ammonia or methylamine into 2-methyl-5-ethylpyridine (793) (71RTC1246), while 2-methoxy-5-arylpyrimidines (794) with... 

Methyl-1,3-diisopropylpseudourea, 170 Methylene compounds, nitrosation of, 395 4-Methylene-2-imidazolidinones, 140 4-Methylene-2-oxazolidinones, 140 2-Methyl-5-ethylpyridine, 96... 

It has been postulated that vinylamine is an intermediate in the catalytic condensation of ammonia with acetylene which leads to either acetonitrile or 2-methyl-5-ethylpyridine, depending on the reaction conditions [80] (Eq. 24). 

Synthetic Methods of Manufacture. Due to rising demand, production of the pyridine bases by large-scale synthesis passed the volume of tar bases extracted from coal tar in the 1960s. By the early 1970s. capacity in the United States for the synthetic manufacture of pyridine, the picolines, and 2-methyl-5-ethylpyridine (MEP) was in the tens of millions of pounds. All of these products can be made by condensation reactions of aldehydes and ammonia, MEP is no lunger made in the United Stales,... 

For production of niacinamide in the past, methylethylpyridine was oxidized with nitric acid to yield niacin, and P-picoline was treated with air and ammonia to produce the nitrile that was then hydrolyzed to niacinamide. A more modern process can produce both niacin and niacinamide from a single feedstock, either P-picoline or 2-methyl-5-ethylpyridine by oxidative ammonolysis, a combination of oxidation and animation. 

Pyridines - The industrially significant pyridine bases are pyridine, 2-methylpyridine (2-picoline) and 2-methyl-5-ethylpyridine (MEP)46. 

In addition to 2-methyl-5-ethylpyridine mentioned above, the following dialkylpyridines have been reduced by the Ladenburg method 3,5-dimethylpyridine,58 3-methyl-4-ethylpyridine,48 and 2,4-dimethylpyridine.48 3,5-Dimethyl-3-piperideine (62) and cis- and iratis-3,5-dimethylpiperidine are obtained from 3,5-dimethylpyri-dine.53... 

Somewhat less useful is the aluminum hydride reduction of quaternary pyridinium salts. Reduction of the salts may be more conveniently performed by the use of sodium borohydride (see Section II, B, 6). Moreover, the aluminum hydride reductions of some dialkyl-pyridinium salts are accompanied by reductive cleavage of the pyridine ring,77 For example, methiodides of 2,5-dimethylpyridine,77 2-methyl-5-ethylpyridine,77 and 2-ethyl-5-methylpyridine61 afford mixtures of the corresponding tetrahydro and hexahydro bases along with a secondary amine, viz., 5-methylaminomethyl-2,4-hexadiene, 5-methylaminomethyl-2,4-heptadiene, and 7-methylamino-6-methyl-2,4-heptadiene, respectively. 

In addition to compounds quoted by Lyle and Anderson," the following quaternary salts have recently been reduced with sodium borohydride ethiodides of pyridine and its homologs, methiodides of 3-ethylpyridine, 4-ethylpyridine, 2-methyl-5-ethylpyridine, and 3-methyl-4-ethylpyridine,102 and the methiodide of 2-benzyl-4-methylpyridine.103 Reductions (NaBH4) of l,2-dimethyl-5-ethyl-pyridinium iodide and l,3-dimethyl-4-ethylpyridinium iodide afford as principal products those 3-piperideines (94, 95) which carry the maximum number of substituents on the double bond, presumably due to hyperconjugation.102... 

SYNS ALDEHYDECOLLIDIKE ALDEHYDINE COLUDINE, ALDEHYDECOLLIDINE 3-ETHYL-6-METHYLPYRIDINE 5-ETHYL-2-.METHYLPYRIDINE 5-ETHYD2-PICOUNE MEP 2-METHYL-5-ETHYLPYRIDINE 6-METHYL-3-ETHYLPYRIDINE METHYL ETHYL PYRIDINE (DOT) 2-METHYL-5-ETHYLPYRIDINE (DOT)... 

ETHYL(PROPYLAMINO)PHOSPHINOTHIOYL)OXY )-2-BUTENOATE see MKB320 2-METHYL-5-ETHYLPYRIDINE see EOSOOO 6-METHYL-3-ETHYLPYRIDINE see EOSOOO METHYL ETHYL PYRIDINE (DOT) see EOSOOO... 

Source Food sources meat, fish, milk, whole grains, yeast. Commercial sources synthetic niacin is made by oxidation of nicotine, quinoline, or 2-methyl-5-ethylpyridine (from ammonia and formaldehyde or acetaldehyde). 

Methyl-5-ethylpyridine Nicotinic Acid, 3-Pyridine carboxylic acid... 

Pyridine derivatives are precursors of many chemical products of medicinal, agricultural, and industrial importance. Pyridine itself is used not only as a solvent, but also as a starting material for pharmaceuticals, herbicides, insecticides, and fungicides. a-Picoline is a precursor for 2-vinylpyridine which is used in the production of an adhesive for textile tire cord. The major use of y-picoline is in the production of isonicotinic hydrazide, an antituberculosis agent. / -Picoline and 2-methyl-5-ethylpyridine are important intermediates in the production of two members of the vitamin B family, nicotinamide, and nicotinic acid (also known as vitamin B3). All this shows there is a substantial need for the production of picolines. The following text describes a novel route to a-picoline which might in the future lead to new processes. 

METHYL ETHYL PYRIDINE or METHYL-2 ETHYL-5 PYRIDINE (French) or 2-METHYL-5-ETHYLPYRIDINE (104-90-5) CgHnN Combustible liquid [explosion limits in air (vol %) 1.1 to 6.6 flashpoint 155°F/68°C also reported at 165°F/73°C autoignition... 

METHYL-5-ETHYLPYRIDINE (104-90-5) Combustible liquid (flash point 155°F/68°C also listed at 165°F/73°C). Violent reaction with strong oxidizers. May form heat-sensitive explosive materials with digold ketenide. Incompatible with alcohols, aldehydes, alkylene oxides, cresols, caprolactam solution, epichlorohydrin, organic anhydrides, glycols, maleic anhydride, phenols. Attacks copper and its alloys. 

Other catalysts, used in types of reactions not listed above, vary with the specific reaction involved. A few examples are cited. For the reaction involving the removal of hydrogen from NHa and CH4 to produce HCN, noble-metal catalysts are used. For the synthesis of benzonitrile from toluene and NHs by splitting out hydrogen, molybdenum trioxide is used. 2-Methyl-5-ethylpyridine is produced by reacting methylvinyl ether and NHs at elevated temperatures and pressures over a titanium phosphate or manganese phosphate catalyst supported on calcined silica. ... 

Nitration of 2-methyl-5-ethylpyridine was successful only in KNH2 and the nitro compound was obtained in 42% yield (eq 19). Apparently NaNH2 is not a strong enough base to form the anion. Only starting material was recovered. 

---