Acyl chlorides reaction with hydrogen

Acyl chlorides react with carboxylic acids to yield acid anhydrides When this reaction is used for preparative purposes a weak organic base such as pyridine is normally added Pyridine is a catalyst for the reaction and also acts as a base to neutralize the hydrogen chloride that is formed... 

Reaction with ammonia and amines (Sec tion 20 14) Acyl chlorides react with am monia and amines to form amides A base such as sodium hydroxide is normally added to react with the hydrogen chio ride produced... 

The preparation of a formyl-substituted aromatic derivative 3 from an aromatic substrate 1 by reaction with hydrogen cyanide and gaseous hydrogen chloride in the presence of a catalyst is called the Gattermann synthesis This reaction can be viewed as a special variant of the Friedel-Crafts acylation reaction. 

Bis(trimethylsilyl) sulphide reacts with acyl silanes in the presence of a cobalt chloride catalyst to afford the corresponding thiocarbonyl derivatives, thioacyl silanes (Scheme 100)214. The reaction is mild and proceeds in good yields. It is also applicable to aldehydes. Thioacyl silanes have been prepared from the corresponding haloacyl silanes by reaction with hydrogen sulphide (vide supra, Section IV.A.3)196. 

The Leukart reaction has also been used in the conversion of dehydroepiandro-sterone into 17/3-formylamino-3/3-formyloxyandrost-5-ene, which on reduction with lithium aluminium hydride afforded 3/3-hydroxy-17/3-me thylaminoandrost-5-ene. Acylation with isocaproyl chloride then furnished the N-methyl-N-isocaproyl steroid (197), after selective ester hydrolysis of the initially formed ON-diacyl derivative. The amide (197) was further converted into its 3,5-cyclo-6-ketone via the 3,5-cyclo-6/3-alcohol and thence by reaction with hydrogen bromide into the corresponding 3/3-bromo-5a-6-ketone which upon dehydrobromination furnished a A2-5a-6-ketone and ultimately the 2-monoacetate of the 2/3,3/3-diol (198) after reaction with silver acetate and iodine. Hydrolysis to the 2/3,3/3-diol (198) gave a separable mixture of the 2/3,3/8-dihydroxy-5a- and -5/3-ketones.88... 

Highly activated aromatic compounds such as dihydric phenols can be acylated by reaction with an aliphatic nitrile in the presence of a Lewis acid, usually zinc chloride, and hydrogen chloride (Scheme 6.24). The Houben-Hoesch reaction is a variation of the Gattermann formylation and proceeds via an iminium salt, which is isolated and subsequently hydrolysed. 

The reaction of acyl chlorides with hydroxy compounds and amines has already been met in previous experiments. Generally, hydroxy compounds, ROH, primary amines, RNHj, and secondary amines, R2NH, react Avith acyl chlorides, the reactive hydrogen being replaced by the acyl group ... 

Certain compounds which contain halogen, other than acyl chlorides, react with amines and form condensation-products as the result of the elimination of a hydrogen halide. The reaction of methylamine with chloroform, CHCI3, in the presence of an alkali is an example of a reaction of this type. In this case, both hydrogen atoms joined to nitrogen unite with chlorine to form hydrochloric acid, and an intermediate compound is probably formed, which is unstable and loses another molecule of the acid. The steps in the reactions may be represented by the following equations —... 

Acyl chlorides react with ethylenediamine and polyamines forming acylated polyamines that can be used in further syntheses. Just as ethylene oxide is added to alkyl amine, so ethyleneimine is added to it in the presence of AICI3 or other Lewis acids to produce polyamines. Polyamines can be prepared also by the reaction of alkyl amine with acrylonitrile with a subsequent catalytic hydrogenation. 

Acyl chlorides react with water, often violently, to give the corresponding carboxylic acids and hydrogen chloride. This transformation is a simple example of addition-elimination and is representative of most of the reactions of this class of compounds. 

The Pd-catalyzed hydrogenoiysis of acyl chlorides with hydrogen to give aldehydes is called the Rosenmund reduction. Rosenmund reduction catalyzed by supported Pd is explained by the formation of an acylpalladium complex and its hydrogenolysis[744]. Aldehydes can be obtained using other hydrides. For example, the Pd-catalyzed reaction of acyl halides with tin hydride gives aldehydes[745]. This is the tin Form of Rosenmund reduction. Aldehydes are i ormed by the reaction of the thio esters 873 with hydrosilanes[746,747]. 

In these reactions the active acylating agent is the carbamyl chloride, formed by the reaction of the isocyanate with hydrogen chloride (137) ... 

Synthesis. Symmetrical diacyl peroxides (20, R = R = alkyl or aryl) are prepared by the reaction of an acyl chloride or anhydride with sodium peroxide or hydrogen peroxide and a base ... 

Mixed chloiide alkoxides aie prepared by reaction with acyl chlorides, metal chlorides, hydrogen chloride, or chlorine (64). 

It would thus appear that O acylation is the normal course of the acylation of enamino ketones. Surprisingly the enamino ketones 49 and 50 undergo reaction with acid chlorides not having an a-hydrogen (e.g., benzoyl and pivalyl chlorides) to give the products of C acylation (133). 

The aromatic sulfonyl chlorides which have no a-hydrogen and thus cannot form sulfenes give acylic sulfones. Thus 1-piperidinopropene on reaction with benzene sulfonyl chloride (9J) gave 2-benzenesulfonyl-l-piperidinopropene (153). Similarly the enamine (28) reacts with p-toluene-sulfonyl chloride to give the 2-p-toluenesulfonylcyclohexanone (154) on hydrolysis (/OS). 

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