Important derivatives of pyridine are niacin, nicotinamide, isonicotinic acid hydrazide, nicotine, strychnine, vitamin B6 and the like. Vitamin B6 is a class of tetrasubstituted pyridine derivatives with coenzyme action. Clinically used for the treatment of pregnancy vomiting, radiation vomiting, isoniazid poisoning, seborrheic dermatitis and pellagra. Pyridine is a colorless or slightly yellow liquid with a weak basic and special odor. It is naturally found in coal tar, shale oil, gas and petroleum. It is miscible with most organic solvents such as water, alcohol, ether, petroleum ether, oil, benzene, chloroform, etc. It is an important chemical raw material and solvent. Pyridine has a structure close to a regular hexagon, similar to benzene, and has the same electronic structure. Due to the electron-withdrawing action of nitrogen atoms in the ring, the electron cloud density at the 2, 4, and 6 positions is lower than the 3,5 position. In the acidic medium, the electrophilic substitution reaction occurs at the 3,5 position, and the nucleophilic reaction such as amination, Alkylation, arylation, and acylation occur at the 2, 4, and 6 positions. Pyridine is a weak tertiary amine which can form water-insoluble salts with various acids (such as picric acid, perchloric acid, etc.) in ethanol solution; since pyridine is basic, it can form pyridine hydrochloride with hydrochloric acid ( C5H5N·HCl). Under the action of nickel catalyst, hydrogenation reduction at 200 ° C and 15 ~ 30 MPa can produce piperidine; it can also be electrolytically reduced to piperidine; its reducibility is easier than benzene. Pyridine is harder to oxidize than benzene, but hydrogen peroxide or peroxyacid can oxidize pyridine to form N-oxidized pyridine, which is an important pyridine derivative. After oxidation by nitrogen atom, it cannot form positively charged pyridinium. An electrophilic substitution reaction that favors the aryl group. Electrophilic substitution of pyridine such as nitration, sulfonation, and halogenation is difficult, but halogenation is slightly easier than the former two. Above 200 ° C, 3,5-dichloropyridine or 3,4.5-trichloropyridine can be obtained. Pyridine can form crystalline coordination compounds with a variety of metal ions.
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Amino compound
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Oxy-containing amino compound
Cycloalkylamines, aromatic monoamines, aromatic polyamines and derivatives and salts thereof
Acyclic monoamines, polyamines and their derivatives and salts
Amide compound
Sulfonic acid amino compound
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Alcohols, phenols, phenolic compounds and derivatives
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2-cycloalcohol
Halogenated, sulfonated, nitrated or nitrosated derivatives of alcohols
Extremely halogenated, sulfonated, nitrated or nitrosated derivatives of phenols
Phenol and its halogenated, sulfonated, nitrated or nitrosated derivatives
Acyclic alcohol
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Nitrogen-containing compound
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Nitrile compound
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Organic derivative of hydrazine or hydrazine
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Terpenoid
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Ether compounds and their derivatives
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Ether, ether alcohol
Halogenation, sulfonation, nitration or nitrosation of ethers, ether alcohols, ether phenols
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Aldehyde
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Carboxylic compounds and derivatives
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Cyclic carboxylic acid
Halogenation, sulfonation, nitration or nitrosation of carboxylic acids
Halogenation, sulfonation, nitration or nitration of carboxylic anhydrides
Carboxylic acid halide
Carboxylic esters and their derivatives
Salt of carboxylic acid ester and its derivatives
Acyclic carboxylic acid
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Hydrocarbon compounds and their derivatives
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Aromatic hydrocarbon
Cyclic hydrocarbon
Hydrocarbon sulfonate
Hydrocarbon halide
Hydrocarbon nitrite
Acyclic hydrocarbon
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Ketone compound
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Alkyl ureas and their derivatives and salts
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Inorganic acid ester
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Heterocyclic compound
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Diazo, azo or azo compound
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Organosilicon compound
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Organometallic compound
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Organic palladium
Organic germanium, cobalt, strontium, barium, gallium, germanium, germanium, germanium, germanium, etc.
Organic calcium
Zirconium
Organic potassium
Organic
Organic lithium
Organic
Organic aluminum
Organotin
Organic manganese
Organic sodium
Organic nickel
Organic titanium
Organic iron
Organic copper
Organotin
Organic zinc
Organic
Organic
Organic germanium, mercury, silver, platinum, etc.
Organic germanium, antimony, bismuth, tungsten, antimony, bismuth, lead, vanadium, molybdenum, chromium, antimony, etc.
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Organic sulfur compound
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Organic phosphine compound
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Organometallic salt
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Organic fluorine compound
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Fluorobenzoic acid series
Fluorobenzonitrile series
Fluorobenzaldehyde series
Fluorobenzyl alcohol series
Fluoroanisole series
Fluoroaniline series
Fluorophenylacetic acid series
Fluorophenol series
Fluorobenzoic acid series
Fluoronitrobenzene series
Fluoropyridine series
Potassium fluoroborate series
Fluorobenzyl alcohol series
Fluorotoluene series
Fluorine red series
Fluoroethane series
Fluoropropane series