Acetates aromatic amines

Joshi et al. [67] developed an efficient and simple one-pot synthesis of some new symmetrical, unsymmetrical, and iV-substituted Hantzsch 1,4-DHPs 48 and 49 using molecular iodine as catalyst by the reaction of aldehydes, 1,3-dicarbonyl compound, and ammonium acetate/aromatic amine in EtOH. This new method has the advantage of good to excellent product yields and shorter reaction times at ambient temperature (Scheme 10.32). 

Acetyl derivatives of aromatic amines may be prepared either witli acetic anhydride or acetic acid or with a mixture of both reagents. Primary amines react readily upon warming with acetic anhydride to yield, in the first instance, the mono-acetyl derivative, for example ... 

Certain ortho substituted derivatives of aromatic amines are difficult to acetylate under the above conditions owing to steric hindrance. The process is facilitated by the addition of a few drops of concentrated sulphuric acid (compare Section IV,47), which acts as a catalyst, and the use of a large excess of acetic anhydride. 

PMMA is not affected by most inorganic solutions, mineral oils, animal oils, low concentrations of alcohols paraffins, olefins, amines, alkyl monohahdes and ahphatic hydrocarbons and higher esters, ie, >10 carbon atoms. However, PMMA is attacked by lower esters, eg, ethyl acetate, isopropyl acetate aromatic hydrocarbons, eg, benzene, toluene, xylene phenols, eg, cresol, carboHc acid aryl hahdes, eg, chlorobenzene, bromobenzene ahphatic acids, eg, butyric acid, acetic acid alkyl polyhaHdes, eg, ethylene dichloride, methylene chloride high concentrations of alcohols, eg, methanol, ethanol 2-propanol and high concentrations of alkahes and oxidizing agents. 

Hydroperoxides have been obtained from the autoxidation of alkanes, aralkanes, alkenes, ketones, enols, hydrazones, aromatic amines, amides, ethers, acetals, alcohols, and organomineral compounds, eg, Grignard reagents (10,45). In autoxidations involving hydrazones, double-bond migration occurs with the formation of hydroperoxy—azo compounds via free-radical chain processes (10,59) (eq. 20). 

Phloroglucinol is Hsted in the Colourindex as Cl Developer 19. It is particularly valuable in the dyeing of acetate fiber but also has been used as a coupler for azoic colors in viscose, Odon, cotton (qv), rayon, or nylon fibers, or in union fabrics containing these fibers (157). For example, cellulose acetate fabric is treated with an aromatic amine such as (9-dianisidine or a disperse dye such as A-hydroxyphenylazo-2-naphthylamine and the amine diazotizes on the fiber the fabric is then rinsed, freed of excess nitrite, and the azo color is developed in a phloroglucinol bath at pH 5—7. Depending on the diazo precursor used, intense blue to jet-black shades can be obtained with excellent light-, bleach-, and mbfastness. 

Reduction. Just as aromatic amine oxides are resistant to the foregoing decomposition reactions, they are more resistant than ahphatic amine oxides to reduction. Ahphatic amine oxides are readily reduced to tertiary amines by sulfurous acid at room temperature in contrast, few aromatic amine oxides can be reduced under these conditions. The ahphatic amine oxides can also be reduced by catalytic hydrogenation (27), with 2inc in acid, or with staimous chloride (28). For the aromatic amine oxides, catalytic hydrogenation with Raney nickel is a fairly general means of deoxygenation (29). Iron in acetic acid (30), phosphoms trichloride (31), and titanium trichloride (32) are also widely used systems for deoxygenation of aromatic amine oxides. 

Acylation. Aromatic amines react with acids, acid chlorides, anhydrides, and esters to form amides. In general, acid chlorides give the best yield of the pure product. The reaction with acetic, propionic, butanoic, or benzoic acid can be catalyzed with phosphoms oxychloride or trichloride. 

Condensation. Depending on the reaction conditions, a variety of condensation products are obtained from the reaction of aromatic amines with aldehydes, ketones, acetals, and orthoformates. 

Nitroso compounds are formed selectively via the oxidation of a primary aromatic amine with Caro s acid [7722-86-3] (H2SO ) or Oxone (Du Pont trademark) monopersulfate compound (2KHSO KHSO K SO aniline black [13007-86-8] is obtained if the oxidation is carried out with salts of persulfiiric acid (31). Oxidation of aromatic amines to nitro compounds can be carried out with peroxytrifluoroacetic acid (32). Hydrogen peroxide with acetonitrile converts aniline in a methanol solution to azoxybenzene [495-48-7] (33), perborate in glacial acetic acid yields azobenzene [103-33-3] (34). 

Contaminants and by-products which are usually present in 2- and 4-aminophenol made by catalytic reduction can be reduced or even removed completely by a variety of procedures. These include treatment with 2-propanol (74), with aUphatic, cycloaUphatic, or aromatic ketones (75), with aromatic amines (76), with toluene or low mass alkyl acetates (77), or with phosphoric acid, hydroxyacetic acid, hydroxypropionic acid, or citric acid (78). In addition, purity may be enhanced by extraction with methylene chloride, chloroform (79), or nitrobenzene (80). 

A Methylanthrapyridone and Its Derivatives. 6-Bromo-3-methylanthrapyridone [81-85-6] (75) is an important iatermediate for manufacturiag dyes soluble ia organic solvents. These solvent dyes are prepared by replacing the bromine atom with various kiads of aromatic amines. 6-Bromo-3-methylanthrapyridone is prepared from 1-methyl amino-4-bromoanthra quin one (43) by acetylation with acetic anhydride followed by ring closure ia alkaU. The startiag material of this route is anthraquiaoae-l-sulfonic acid (16). 

The dienone complex is an efiective phenylating agent for aromatic amines t.g., aniline and triearbonylcyclohexadienoneiron in glacial acetic acid at 75° overnight gives diphenylamine in 95% yield. ... 

Complete reduction to the alkane occurs when palladium on carbon (Pd/C) is used as catalyst, but hydrogenation can be stopped at the alkene if the less active Lindlar catalyst is used. The Lindlar catalyst is a finely divided palladium metal that has been precipitated onto a calcium carbonate support and then deactivated by treatment with lead acetate and quinoline, an aromatic amine. The hydrogenation occurs with syn stereochemistry (Section 7.5), giving a cis alkene product. 

Belyaev et al. (1989) demonstrated that weakly basic aromatic amines which have a low solubility in diazotizing systems can be diazotized smoothly and with excellent yields (>97%) in mixtures of acetic acid and polyphosphoric acid. 

Combined effect of BTMA Br3 and ZnCl2 in acetic acid provides a new excellent bromination procedure for arenes. That is, while such reactive aromatic compounds as phenols, aromatic amines, aromatic ethers, and acetanilides have been easily brominated by BTMA Br3 in dichloromethane in the presence of methanol, the reaction of arenes, less reactive compounds, with BTMA Br3 in dichloromethane-methanol did not proceed at all, even under reflux for many hours. However, arenes could be smoothly brominated by use of this agent in acetic acid with the aid of the Lewis acid ZnCl2 (Fig. 13) (ref. 16). 

Primary (R = H) and secondary aromatic amines react with alkenes in the presence of thallium(III) acetate to give vie- diamines in good yields. " The reaction is not successful for primary aliphatic amines. In another procedure, alkenes can be diaminated by treatment with the osmium compounds R2NOSO2 and R3NOSO (R = t-Bu)," analogous to the osmium compound mentioned at 15-51. The palladium-promoted method of 15-51 has also been extended to diamination. " Alkenes can also be diaminated indirectly by treatment of the aminomercurial compound mentioned in 15-51 with a primary or secondary aromatic amine. 

In a related reaction, primary aromatic amines have been oxidized to azo compounds by a variety of oxidizing agents, among them Mn02, lead tetraacetate, O2 and a base, barium permanganate, and sodium perborate in acetic acid, tert Butyl hydroperoxide has been used to oxidize certain primary amines to azoxy compounds. 

In the first step tin(Il) chloride in acetic acid solution reduces the aromatic nitro groups to amino groups. The aromatic amines produced then react with fluorescamine in weakly basic medium to yield fluorescent derivatives (cf. reagent monograph Fluorescamine Reagent , Volume la). 

In a first step oxidized aromatic amines are reduced with titanium(III) chloride in glacial acetic acid solution and then condensed to a colored Schiff s base with 4-(dimethylamino)-benzaldehyde (cf. Chapter 2). 

Dipping solution For aromatic amines Dissolve O.S g l,2-naphthoquinone-4-sulfonic add sodium salt in 30 ml water and add 65 ml ethanol and S ml acetic add [5]. 

For aromatic amines Dissolve 0.5 g 1 -naphthoquinone-4 sulfonic acid sodium salt in 95 ml water and treat with 5 ml glacial acetic acid [1,6] if necessary, filter off the insoluble part [1],... 

Note Other aromatic amines, e. g. 1- or 2-naphthylamine in acetic acid solution (Griess reagent), can be used as coupling agent instead of N-(l-naphthyl)-ethylenediamine ... 

Similar reactions with primary and secondary amines result in the formation of 3-aUcylamino- or 3-dialkylamino-l-butyne in 30-80% yield (TON = 3-9) [243-247]. In one example, the TOP could be estimated as 0.2 h" [246]. Enamines were proposed as reaction intermediates. It was later shown that enamines effectively react with terminal aUcynes, including acetylene, to afford the expected aminoalkynes without catalyst or, more rapidly, sometimes exothermically, in the presence of CujCf [248]. Aromatic amines do not react under the same conditions. However, in the presence of organic acids, e.g. acetic acid, 3-arylamino-l-butynes can be isolated in moderate yields (Eq. 4.59) [246, 247, 249]. 

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