Iodine pyridine

If cold benzene is treated with bromine in the absence of sunlight, very little reaction occurs if, however, a halogen carrier, such as iron, iodine, pyridine, etc., is also present, a rapid reaction by substitution occurs, forming first... 

Iodine, Pyridine, Sulfur trioxide Anon., J. Chem. Educ., 1973, 50, A293... 

Ethyl sulfate Flammable liquids Fluorine Formamide Freon 113 Glycerol Oxidizing materials, water Ammonium nitrate, chromic acid, the halogens, hydrogen peroxide, nitric acid Isolate from everything only lead and nickel resist prolonged attack Iodine, pyridine, sulfur trioxide Aluminum, barium, lithium, samarium, NaK alloy, titanium Acetic anhydride, hypochlorites, chromium(VI) oxide, perchlorates, alkali peroxides, sodium hydride... 

Fig. 16 lodination of 4-pentenoic acid and 4-penten-l-ol with iodine/pyridine or di-4-chlorophenyltellurium(IV) diiodide (5)/pyridine. 

The stabilities of pyridine-2- and -4-diazonium ions resemble those of aliphatic rather than benzenoid diazonium cations. Benzenediazonium ions are stabilized by mesomerism which involves electron donation from the ring, but such electron donation is unfavorable in 2- and 4-substituted pyridines. On formation, pyridine diazonium cations normally immediately react with the aqueous solvent to form pyridones. However, by carrying out the diazotization in concentrated HC1 or HBr, useful yields of chloro- and bromopyridines 752 can be obtained. Iodinated pyridines can be obtained in good yield using the Sandmeyer reaction. Aminopyridazines and -pyrazines, 2- and 4-aminopyrimidines, and amino-1,2,4-triazines behave similarly. Nucleophilic fluorination via the BalzSchiemann reaction of diazonium fluoroborates yields fluoropyridines, including 2-fluoropyridines. Fluoroborates can also be converted into fluoro compounds by ultraviolet irradiation. 

Catalytic enantioselective versions of the inverse electron demand cycloaddition have also been reported. For example, the C-(diisopropylamino)carbonyl A -phenyl nitrone reacted with 7-substituted allylic alcohols in the presence of diethylzinc, iodine, pyridine A -oxide, and a catalytic amount of enantiopure DIPT to afford 3,5-m-disubstituted isoxazolidines with high enantioselectivity (Scheme 124) <2002CL302>. Enantioselective cycloaddition of nitrones to enol ethers was achieved in the presence of chiral binaphthol-aluminium and chiral copper-bis(oxazoline) catalysts <1999JA3845, 1999CC811, 1999JOC2353, 2000JOC9080>. 

N(2-Indolylethyl)glutarimide, 871 Inosine, 740-741 N-oxide, 754 Inositol, 179 -2-carboxylic acid, 326 derivatives, 740 hexamethyl ether, 683 Inositols, 256 Iodic acid, 496 Iodine, 495-500,1107, 1281 Iodine azide, 500-501 Iodine isocyanate, 501 Iodine monobromide, 501-502 Iodine monochloride, 258, 502 Iodine-Morpholine complex, 502-SOS Iodine pentafluoride, 503 Iodine-Pyridine, 503-504 Iodine-Silver salts, 504 lodoacetamide, 504-505 lodoacetone, 1188... 

Iodine-Pyridine, Methyl ketones of the types ArCOCHs and R2CHCOCH3 react with iodine in pyridine solution to give the pyridinium iodides in yields sometimes... 

Water-soluble iodine contrast agents form the largest group of contrast agents in use today. They were originally developed from mono-iodinated pyridine derivatives (in the 1920s as by products of research for drugs to treat syphilis). Further development to reduce toxicity led to tri-iodinated benzene derivatives. 

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