Sandmeyer reaction iodination

Preparation by diazotization of 4-amino-2-hydroxyacetophenone and replacement of the diazonium group by iodine (Sandmeyer reaction) (46%) [1956],... 

The diazonium salts usually decompose when warmed with water to give a phenol and nitrogen. When treated with CuCl, CuBr, KI, the diazo group is replaced by chlorine, bromine or iodine respectively (Sandmeyer reaction). A diazonium sulphate and hydroxyl-amine give an azoimide. The diazonium salt of anthranilic acid (2-aminobenzoic acid) decomposes to give benzyne. ... 

Sandmeyer reactions used have included the preparation of the 5-iodo compound from the diazonium salt of 5-amino-8-isoquinolinol further reaction with iodine monochloride gave 5,7-diiodo-8-isoquinolinol (66JMC46). Treatment of 1-chloroisoquinoline with iodide gave the 1-iodo analogue (47%) (67YZ1342). 

Halo-de-diazoniations are a series of reactions in which the replacement of the dia-zonio group changes from a heterolytic de-diazoniation in the case of the fluorination (Balz-Schiemann reaction) to transition metal-catalyzed chlorination and bromination (Sandmeyer reaction) and finally to iodination and astatination where no catalyst is necessary due to the favorable redox potentials of I and At- (I- E° = 1.3 V). 

Again the Sandmeyer reaction is frequently used to convert amino- to halo-isoquinolines. The diazonium salt of 5-amino-8-isoquinolinol (14) on treatment with potassium iodide and iodine gives the 5-iodophenol (15). Iodination of the hydrochloride of (15) with iodine monochloride in ethanol gives (16 Scheme 9) (66JMC46). 

In this nexus, the groups of van Lier and Torres independently reported in 1997 the preparation of a highly soluble A3B-type zinc(II) Pc, where A represents substituted tert-butyl isoindolines, whereas B stands for an iodine-containing unit (Fig. 3). The former group started with the preparation of mononitro Pc 1 obtained through statistical condensation of 4-nitrophthalonitrile and 4-fert-butylphthalonitrile in the presence of zinc acetate [41], Subsequent reduction of Pc 1 provided the amino function which was then subjected to a Sandmeyer reaction to furnish the targeted... 

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. 

The replacement of the diazonium group by chlorine or bromine is accomplished using the Sandmeyer reaction Replacement with fluorine and iodine can be achieved by variations of this reaction. 

Copper(I) iodide is unsatisfactory for use in the Sandmeyer reaction because of its insolubility. The iodo group is introduced by warming the diazonium salt solution in aqueous potassium iodide solution (Scheme 8.17). This method is one of the best means of introducing iodine into an aromatic ring. A one-electron reduction by the iodide ion is thought to initiate a radical reaction in a similar way to the Cu(I) ion. 

Uses Feed additive nutrient dietary supplement in table salt as source of dietary iodine catalyst in Sandmeyer reactions cloud seeding heat stabilizer for glass fiber-reinforced polyamides antioxidant/stabilizer... 

Conversion of diazonium compounds to aryl chlorides, bromides, or cyanides is usually accomplished using cuprous salts, and is known as the Sandmeyer reaction. Since a CN group is easily converted to a CO2H group (eq. 10.13), this provides another route to aromatic carboxylic acids. The reaction with KI gives aryl iodides, usually not easily accessible by direct electrophilic iodination. Similarly, direct aromatic fluorination is difficult, but aromatic fluorides can be prepared from diazonium compounds and tetrafluoroboric acid, HBF4. 

Preparation by diazotization of 3-amino-2-hydroxy-acetophenone with sodium nitrite in dilnte snlfnric acid at 0°, and replacement of the diazonium gronp by iodine with potassinm iodide at 65° (Sandmeyer reaction) [1920,1965,2036], (50%) [1965]. 

Cut Sandmeyer reaction When an aryldiazonium salt is treated with Cul, the diazonium group is replaeed with an iodine atom. 

Gattermann Reaction.—The reaction was further modified by Gat-termann who found that finely divided metallic copper could be used with even greater advantage. The Sandmeyer and Gattermann reactions are not applicable, however, for the formation of the iodine products. To form these the diazonium salt, usually the acid sulphate, is heated with a solution of potassium iodide. 

Haas, R., Schmidt, T. C., Steinhach, K., and von Low, E., Derivatization of aromatic amines for analysis in ammunition wastewater II Derivatization of methyl anilines by iodination with a Sandmeyer-like reaction. Frescenius, J. Anal Chem., 359, 497-501, 1997. 

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