Picholine

Methylpyridine. _{C 6} H ₇ N (93.13). Found in tar base oil, bone oil, etc. There are three isomers depending on the position of the methyl group. [ I ] α-picoline (2-methylpyridine): A colorless liquid with an unpleasant odor. It is synthesized by heating cyclohexylamine to 350°C in the presence of excess ammonia and zinc chloride, and isomerizing it. Melting point -69.9°C, boiling point 129°C. 0.950. 1.4983. K _b 1.05×10 ^-8 (25°C). The hydrogen in the methyl group is a highly reactive active hydrogen. It is irritating to the respiratory tract. LD ₅₀ 790 mg/kg (rat, oral). [ II ] β-picoline (3-methylpyridine): A liquid with a sweet, non-obvious odor. Melting point -17 to -18 °C, boiling point 143 to 144 °C. 0.9613. 1.5043. K _b 1.1 x 10 ^-8 (25 °C). The reactivity of the methyl group is not as high as in the other isomers. Used as a raw material for the manufacture of nicotinamide and insecticides. [ III ] γ-picoline (γ-picoline, 4-methylpyridine): Liquid with a sweet odor. Melting point 4.3 °C, boiling point 145 °C. 0.9571. 1.504. K _b 1.1 x 10 ^-8 (25 °C). Used as a raw material for the synthesis of isonicotinic acid. A common property of these isomers is that they are soluble in water, ethanol, and ether. When reduced, they become the corresponding pipecoline, and when oxidized, they become the corresponding pyridine carboxylic acid. They form addition compounds with metal salts and hydrogen halides. They are used as solvents and raw materials for dyes and synthetic resins.

Source: Morikita Publishing "Chemical Dictionary (2nd Edition)" Information about the Chemical Dictionary 2nd Edition

methylpyridine．C₆H₇N(93.13)．タール塩基油，骨油などのなかに存在する．メチル基の位置により次の3種類の異性体がある．【Ⅰ】α-ピコリン(α-picoline，2-methylpyridine)：不快臭のある無色の液体．シクロヘキシルアミンを過剰のアンモニアと塩化亜鉛の存在下に350 ℃ に加熱，異性化させて合成する．融点－69.9 ℃，沸点129 ℃．0.950．1.4983．K_b 1.05×10^－8(25 ℃)．メチル基の水素は反応性に富む活性水素．呼吸器に対する刺激性がある．LD₅₀ 790 mg/kg(ラット，経口)．【Ⅱ】β-ピコリン(β-picoline，3-methylpyridine)：甘い，不快でない臭いをもつ液体．融点－17～－18 ℃，沸点143～144 ℃．0.9613．1.5043．K_b 1.1×10^－8(25 ℃)．ほかの異性体ほどメチル基の反応性は大きくない．ニコチン酸アミドや殺虫剤の製造原料に用いられる．【Ⅲ】γ-ピコリン(γ-picoline，4-methylpyridine)：甘味臭のある液体．融点4.3 ℃，沸点145 ℃．0.9571．1.504．K_b 1.1×10^－8(25 ℃)．イソニコチン酸の合成原料に用いられる．これらの異性体に共通の性質は，水，エタノール，エーテルに可溶．還元すれば対応するピペコリンとなり，酸化すれば対応するピリジンカルボン酸となる．金属塩やハロゲン化水素と付加化合物をつくる．溶剤として用いられ，染料や合成樹脂の原料として使われている．

出典　森北出版「化学辞典（第2版）」化学辞典 第2版について　情報