Benzoylation, amine

N-Oxidation of the starting compounds yielded compounds 3-10. N-Benzoylated amines undergo hydroxylation when incubated with yeast. Preparation of S-Methylated Derivatives O-Substituted Structural and Functional Analogues... 

The von Braun degradation of tertiary cyclic amines by cyanogen bromide1149,1150 is less important as a preparative reaction than the treatment of benzoyl amines with PX5, but it plays a role in the determination of the structure of alkaloids (see, e.g.9 Bartlett et al.1151). 

Scheme 14.60 Ni-catalysed qrclisation of Af-benzoyl aminals in the presence of...

Ni(COD)2/dppf catalyses the cyclisation of N-benzoyl aminals in the presence of a stoichiometric Lewis acid, forming isoindolinones in 43-76% yields. The reaction may occur via an iminium-ion intermediate formed by reaction of iV-benzoyl aminals with Lewis acid. Reaction of the iminium-ion intermediate with electron-rich Ni(0) leads to cyclisation products (Scheme 14.60). ... 

Benzoyl cyanide generated in this way smoothly benzoylates amines in the presence of alcohols (91-99%). 

The reaction of 1 equiv of racemic amines was carried out with 0.5 equiv of (S)-51 to furnish the corresponding chiral N-benzoylated amines with good conversion (48-50%) and selectivity factor (25-60). The (S)-isomer of 51 produced the (S) isomer of the benzoylated amines. The unreacted amines were further converted to N-benzoyl amides and found to possess (J )-configuration. 

Note. PRIMARY ALIPHATIC AMINES. The lower amines are gases or low-boiling liquids (b.ps. CHjNH, 7 CiHjNH, 17 CH,(CH2,>,NH 49 (CHg)jCHNHa, 34 ) but may be encountered in aqueous or alcoholic solution, or as their crystalline salts. They are best identified as their benzoyl, or toluene-/>-sulphonyl derivatives (c/. (C) above), and as their picrates when these are not too soluble. This applies also to benzylamine, CjHsCHjNH, b.p. 185 also to ethylenediamine, usually encountered as the hydrate, NHj (CHj)j NH2,HjO, b.p. 116 , for which a moderate excess of the reagent should be used to obtain the di-acyl derivative. (M.ps., pp. 55 55 )... 

In general, nitro-hydrocarbons are most readily identified by reduction to the corresponding amine (above), which is then identified as its benzoyl or other derivative (p. 374). (M.ps., pp. 550-551.)... 

Z>) Benzoylation. Proceed exactly as for benzoylation of amines (Test 3 (a), p.374), but use a suspension of the finely ground nitroaniline in the 10% NaOH solution. This preparation of the benzoyl derivatives is rarely necessary, however, as the above acetylation proceeds very satisfactorily. (M.ps., p. 550.)... 

Primary and Secondary Amines. Picrates (pp. 374, 376), Acetyl derivatives (pp. 373, 376), Benzoyl derivatives (pp. 374, 376), Toluene-p-sulphonyl and benzene-sulphonyl derivatives (pp. 374, 376), Phenylurea derivatives (pp. 374, 377)-... 

The experimental technique is similar to that given under Aromatic Amines, Section IV,100,2. The following alternative method may also be used. Mix together 0 -5-0 - 8 ml. of the polyhydroxy compound, 5 ml. of pyridine and 2 -5 ml. of redistilled benzoyl chloride in a 50 ml. flask. 

In general, benzoylation of aromatic amines finds less application than acetylation in preparative work, but the process is often employed for the identification and characterisation of aromatic amines (and also of hydroxy compounds). Benzoyl chloride (Section IV, 185) is the reagent commonly used. This reagent is so slowly hydrolysed by water that benzoylation can be carried out in an aqueous medium. In the Schotten-Baumann method of benzoylation the amino compound or its salt is dissolved or suspended in a slight excess of 8-15 per cent, sodium hydroxide solution, a small excess (about 10-15 per cent, more than the theoretical quantity) of benzoyl chloride is then added and the mixture vigorously shaken in a stoppered vessel (or else the mixture is stirred mechanically). Benzoylation proceeds smoothly and the sparingly soluble benzoyl derivative usually separates as a solid. The sodium hydroxide hydrolyses the excess of benzoyl chloride, yielding sodium benzoate and sodium chloride, which remain in solution ... 

Benzoyl derivatives. Both primary and secondary amines form benzoyl derivatives under the conditions of the Schotten-Baumann reaction (see Section IV,52 and preceding discussion). 

The following alternative procedure is sometimes useful. Heat the amine with the theoretical quantity of benzoyl chloride (if the molecular weight is unknown, use an equal weight of benzoyl chloride in the preliminary experiment) to 100° for 20-30 minutes. Allow to cool, add excess of 5 per cent, sodium hydroxide solution and shake, if necessary,... 

The Schotten - Baumann method of benzoylation with benzoyl chloride in the presence of aqueous sodium hydroxide may be used. Full details are given under Amines Section IV.lOO, 2. 

This acid chloride is much less reactive than acetyl chloride and indeed it may be employed to benzoylate a primary or secondary amine in the presence of a dilute... 

Benzoyl chloride test (for primary and secondary amines). Place 0-5 ml. (or 0 5 g.) of the compound, 10 ml. of 5 per cent, sodium hydroxide solution and 1 ml. of benzoyl chloride (CAUTION) in a test-tube, stopper the tube and shake until the odour of benzoyl chloride disappears. Examine the properties of the substance formed. 

Benzenesulphonyl chloride test. Proceed as in the benzoyl chloride test, but use 15-20 ml. of 5 per cent, sodium hydroxide solution. Examine the product when the odour of the sulphonyl chloride has disappeared. (If no reaction has occurred, the substance is probably a tertiary amine.) If a precipitate appears in the alkaline solution, dilute with about 10 ml. of water and shake if the precipitate does not dissolve, a secondary amine is indicated. If the solution is clear, acidify it cautioiosly to Congo red with dilute hydrochloric acid a precipitate is indicative of a primary amine. 

Benzoyl peroxide Direct sunlight, sparks and open flames, shock and friction, acids, alcohols, amines, ethers, reducing agents, polymerization catalysts, metallic naph-thenates... 

Benzoyl chloride is an important benzoylating agent. In this use the benzoyl radical is introduced into alcohols, phenols, amines, and other compounds through the Friedel-Crafts reaction and the Schotten-Baumaim reaction. Other significant uses are in the production of benzoyl peroxide [94-56-0], benzophenone [119-61-9], and in derivatives employed in the fields of dyes, resins, perfumes, pharmaceuticals, and as polymerization catalysts. 

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