Amines, chlorination

Acid. The reaction requires only enough acid to generate the ferrous ion which is needed to participate in the first step. Alternatively, a ferrous salt can be added directiy. Generally 0.05 to 0.2 equivalents of either hydrochloric or sulfuric acid is used, but both acids have their drawbacks. Hydrochloric acid can cause the formation of chlorinated amines and sulfuric acid can cause the rearrangement of intermediate aryUiydroxylamines to form hydroxyaryl amines. Occasionally an organic carboxyUc acid such as acetic or formic acid is used when there is a danger of hydrolysis products being formed. 

The chemistry of NH2CI involves chlorination, amination, addition, condensation, redox, acid—base, and decomposition reactions. Monochloramine... 

A three-step reaction sequence starting from /3-amino alcohol 212 has been utilized in the synthesis of 2-cyanoazetidine (Scheme 42) <2002TA297, 2006SL78>. The A-benzyl-substituted /3-amino alcohol was first N-cyanomethylated to give the corresponding A-benzyl-A-cyanomethyl /3-amino alcohol 213. The latter compound was stereoselectively transformed into chlorinated amine 214 using thionyl chloride. An intramolecular alkylation of... 

RELATIVE REACTIVITY AND SELECTIVITY OF N-CHLORINATED AMINES IN TRIFLUOROACETIC ACID... 

Amount of Acid Used. This reaction requires the presence of small amounts of ferrous ion to act as a catalyst. Generally about 0.05-0.2 of an equivalent of acid is used. The acids usually employed in the reduction process are hydrochloric and sulfuric. It should be borne in mind that hydrochloric acid sometimes causes the formation of small amounts of chlorinated amines whereas sulfuric acid may rearrange the intermediate arylhydroxylamines to hydroxyarylamines and cause the formation of darker amines in lower yields, particularly in the case of solid amines. Where the danger of hydrolysis or contamination by such products exists, acetic or formic acid is employed instead. The disadvantages in the use of sulfuric acid appear to be minimized when the sulfuric acid is introduced as sodium acid sulfate (niter cake). When used alone or preferably in conjunction with a calculated quantity of sodium chloride, a very economical and satisfactory promoter is obtained. For example, 2.4 lb of sodium chloride with 6 lb of niter cake per 100 lb of nitro compound gives satisfactory results. The niter cake is first ground and is added, along with the sodium chloride, to the water and finely divided iron in the reducer. 

In the previous section the adsorption concept was entered of adsorption molecular electrostatic potential and it was remarked that the first and rather acceptable approximation could be obtained by its help for constructing hydrate cover of any type of solid surface. However, within the framework of notions on MESP it is also possible to predict some other important properties of adsorption complexes of polar molecules on silica surface. Thus, it was shown in [ 137] that hydrophility of the hydroxylated surface of silicion dioxide could be explained by availability of local minima of the p potential within the subsurface region created by the atoms of surface functional groups and solid substrate. Here in water this approach was applied to explain adsorption properties of completely chlorinated, aminated, and hydrogenated surfaces [128]. 

One of the disadvantages of traditional macroligands is a relatively poor utilization of their functional groups. Therefore, extensive studies are being carried out to find new types of macroligands (16). The most widely used methods for these purposes consist in the chemical modification of the carrier polymer surface (i.e., oxidation, chlorination, amination, phosphorylation, etc.). The difficulties vhich are encountered in doing so are diversity of the reaction routes and uncontrolled transformations both through the layer... 

Disubstituted-4-bridged Sulfonamides. All of the 2,3-disubstituted isomers that we ve prepared were made from the acid-thioether 23. In this case the acid is used to direct metalation to the 2 position, and is quenched with a variety of electrophiles yielding 43. The acid is then esterified prior to oxidative chlorination/amination. 

Bridgcd Sulfonamides The methods available for the preparation of the sulfonamide bridge at the 3 and 4 position of the pyrazole are somewhat limited by the type of reactions that can be supported at these positions. In contrast to this, numerous methods are available for the introduction of the sulfonamide at the 5 position. They include (a) Meerwein Reaction/amination (b) oxidative chlorination/amination and (c) metalation followed by trapping of the resultant anion with sulfur dioxide or an equivalent. 

For example, Meerwein Reaction of 78 followed by displacement of the resultant chloride with the sodium salt of benzylmercaptan provides 79. Conversion of the ester to the amide followed by oxidative chlorination/amination yields the sulfonamide 81. 

Rozenfeld investigated hetero-alkylated amines and urotropine hydroiodide, and found them to be more effective than the unsubstituted amines. Chlorinated amines were also investigated by Tamura et al. Recently, Tagmazyan et al. discovered that alkyl(2-hydroxyethyl)dimethylammonium bromides are effective corrosion inhibitors for steel in HCI. Aldoximes and ketoximes can also be very effective, according to Costain and Terry. ... 

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