Anilines iodinated

Magnetic resonance should prove a useful tool in facilitating identification of coordination sites in complexes. For example , in the aniline-iodine complex, a large selective downfield shift is observed for the N-H protons on complex formation. Such a large deshielding of these protons can only indicate that charge is indeed transferred from nitrogen and that this is the site of coordination with iodine. 

Aniline.—Burns with a very smoky flame, clouds of soot being produced. Typical of many aromatic substances. i,2 Dibromoethane.—Does not burn until vapour becomes hot and then burns with a slightly smoky flame. Typical of substances rich in halogens such as cldoroform, chloral hydrate, and carbon, tetrachloride. (Note, however, that iodoform evolves copious fumes of iodine when heated in this way.)... 

Into a 1-litre beaker, provided with a mechanical stirrer, place 36 - 8 g. (36 ml.) of aniline, 50 g. of sodium bicarbonate and 350 ml. of water cool to 12-15° by the addition of a little crushed ice. Stir the mixture, and introduce 85 g. of powdered, resublimed iodine in portions of 5-6 g, at intervals of 2-3 minutes so that all the iodine is added during 30 minutes. Continue stirring for 20-30 minutes, by which time the colour of the free iodine in the solution has practically disappeared and the reaction is complete. Filter the crude p-iodoaniline with suction on a Buchner funnel, drain as completely as possible, and dry it in the air. Save the filtrate for the recovery of the iodine (1). Place the crude product in a 750 ml. round-bottomed flask fitted with a reflux double surface condenser add 325 ml. of light petroleum, b.p. 60-80°, and heat in a water bath maintained at 75-80°. Shake the flask frequently and after about 15 minutes, slowly decant the clear hot solution into a beaker set in a freezing mixture of ice and salt, and stir constantly. The p-iodoaniline crystallises almost immediately in almost colourless needles filter and dry the crystals in the air. Return the filtrate to the flask for use in a second extraction as before (2). The yield of p-iodoaniline, m.p. 62-63°, is 60 g. 

Molecular iodine is not a very powerful halogenating agent. Only very reactive aromatics such as anilines or phenolate anions are reactive toward iodine. Iodine monochloride can be used as an iodinating agent. The greater electronegativity of the... 

Fig. 36 Dependence of the area of the chromatogram zone at constant amount of applied substance (1 pg) on the reagent employed, top relief representation, below zone areas projected on one another Iodine vapor reacts least sensitively here, aniline-phthalate most sensitively and the GOD reaction (glucose oxidase reaction) most specifically [2161...

A number of dihydroquinolines have been prepared by treating aniline derivatives with acetone or mesityl oxide in the presence of iodine. In these cases aromatization to the fully unsaturated quinoline would require the loss of methane, a process known as the Riehm quinoline synthesis. Such Skraup/Doebner-von Miller-type reactions are often low yielding due to large amounts of competing polymerization. For example, aniline 37 reacts with mesityl oxide to give dihydroquinolines 39, albeit in low yield. ... 

Interestingly the Skraup/Doebner-von Miller reaction has been used to prepare a number of spiro-compounds. Aniline was reacted with enone 42 in the presence of iodine to yield dihydroquinoline 43 in acceptable yields. 

Reaction of aniline derivatives with 4-chlorobutyroyl chloride followed by cyclization with sodium ethoxide and subsequent thionation promoted by sonication gave the corresponding A -arylpyrrolidine-2-thiones 126. Zinc-mediated condensation of diethyl bromomalonate with 126 using iodine as activator gave the vinylogous urethanes 127 whose cyclization with PPA gave the tricyclic compound 128 which upon hydrolysis afforded the acid 129 (96TL9403). 

Using iodine as their starting point, they experimented with a series of compounds including the anilines and a series of metals near the bottom of the periodic table. Lead turned out to be the most effective of the additives tested. But lead alone caused a number of problems, including the accumulation of Its oxide in engine components, and particularly the cylinders, valves, and spark plugs. 

Fleischer1 prepared benzylaniline by heating aniline with benzyl chloride at i6o°. This reaction may be very violent and always leads to mixtures. Bernthsen and Trompetter 2 reduced thiobenzanilide with zinc and hydrochloric acid or sodium amalgam, while O. Fischer 3 reduced bcnzalaniline with sodium and alcohol, to benzylaniline. Knoevenagel4 obtained a 32 per cent yield of benzylaniline from benzyl alcohol and aniline in the presence of iodine. Ullmann5 describes the preparation of benzylaniline from benzyl chloride and excess of aniline at low temperatures. 

For substituted anilines (Thompson and Williams, 1977) and for 1-naphthylamine and a series of derivatives thereof (Castro et al., 1986a), k2 and the ratio Ar 2/Ar3 have been determined for nucleophilic catalysis with Cl-, Br-, SCN-, and SC(NH2)2. The values of k2 correspond fairly well to those found for the diazotization of aniline, but those of Ar 2/Ar3 increase markedly in the above sequence (Table 3-1). As k3 is expected to be independent of the presence of Cl- or Br- and to show little dependence on that of SCN- or thiourea, the increase in k 2/k3 for this series must be due mainly to 2. Indeed, the value of log(Ar 2/Ar3) shows a linear correlation with Pearson s nucleophilicity parameter n (Pearson et al., 1968). This parameter is based on nucleophilic substitution of iodine (as I-) in methyl iodide by various nucleophiles. The three investigations on nucleophilic catalysis of diazotization demonstrate that Pearson s criteria for bimolecular nucleophilic substitution at sp3 carbon atoms are also applicable to substitution at nitrogen atoms. 

In deducing from the resulting kinetic equation the nature of the electrophile and how it is produced it is important to represent all the reagents present in terms of the species which they may produce. In this way it is possible to eliminate many negative or fractional orders in reagent and generally obtain a simpler kinetic equation. For example, the observed rate law in the uncatalyzed iodination of aniline can be written21,22 as... 

One of the best methods for the introduction of iodine into aromatic rings is the reaction of diazonium salts with iodide ions. Analogous reactions with chloride, bromide, and fluoride ions give poorer results, and 14-25 and 13-20 are preferred for the preparation of aryl chlorides, bromides, and fluorides. However, when other diazonium reactions are carried out in the presence of these ions, halides are usually side products. Aniline has also been converted to fluorobenzene by treatment with t-BuONO and Sip4 followed by heating. A related reaction between PhN=N—N C4Hg and iodine gave iodobenzene. ... 

Iodine vapor Anisaldehyde reag GOD reag Anthrone reag Aniline phth reag... 

PART 2 HALOGENATED (CHLORINE, BROMINE, AND IODINE) PHENOLS AND ANILINES... 

Quinone may be prepared by the oxidation of aniline with dichromate or manganese dioxide and sulfuric acid.1 This is a more feasible commercial method than the one given. However, the oxidation of hydroquinone is more rapid and convenient and, hence is more desirable for use in the laboratory. Various materials have been oxidized by chemical means to give quinone they are quinic acid,2 hydroquinone,3 benzidine,4 -phenylene-diamine,5 sulfanilic acid,6 / -phenolsulfonic acid,7 arbutin,8 aniline black,9 and the leaves of various plants.10 Quinone is also formed by several other methods by the fermentation of fresh grass 11 by the action of iodine on the lead salt of hydroquin-... 

TMBA-IC12 (see Table 2.23) is added to the aniline (5.37 mmol) in CH2C12 (50 ml) and MeOH (20 ml) at room temperature and the mixture is stirred for 30 min and then filtered and concentrated. Aqueous NaHS03 (5%, 20 ml) is added to the residue and extracted with Et,0 (4 x 40 ml). The dried (MgS04) extracts are evaporated to yield the iodinated aniline. 

Torrance obtained a sample that showed ferromagnetic properties with a high Curie temperature by a reaction of 1,3,5-triaminobenzene with iodine under rather drastic conditions (Torrance et al., 1987). A charge-transfer complex of iodine with an aniline-black-type polymer [32], a heteroatom-containing analogue to [14 ] (Johannsen et al., 1989), may have been... 

The kinetics of iodination of aniline and / -toluidine by iodine in acidified aqueous methanol have been determined at various solvent compositions and temperatures. It was deduced that HOI was the effective electrophile under the reaction conditions. 

On this basis it is possible to compare directly the reactivities in aqueous bromination and iodination of dihydrodiazepine base and dihydrodiazepinium cation with those of para substitution in aniline, phenol, and phenox-ide ion (UP3), as shown in Table II. 

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