Hydrogenation acid chlorides

The presence of the base brings about the irreversible elimination of hydrogen chloride between the acid chloride and the acid the resulting p3rridine hydrochloride precipitates out as the reaction progresses. 

By passing a mixture of carbon monoxide and hydrogen chloride into the aromatic hydrocarbon in the presence of a mixture of cuprous chloride and aluminium chloride which acts as a catalyst (Gattermann - Koch reaction). The mixture of gases probably reacts as the equivalent of the unisolated acid chloride of formic acid (formyl chloride) ... 

From acid chlorides by selective hydrogenation in the presence of a catalyst (palladium deposited upon a carrier, which is usually barium sulphate but is... 

The procedure is to pass purified hydrogen through a hot solution of the pure acid chloride in toluene or xylene in the presence of the catalyst the exit gases are bubbled through water to absorb the hydrogen chloride, and the solution is titrated with standard alkali from time to time so that the reduction may be stopped when the theoretical quantity of hydrogen chloride has been evolved. Further reduction would lead to the corresponding alcohol and hydrocarbon ... 

To the cold acid chloride add 175 ml. of pure carbon disulphide, cool in ice, add 30 g, of powdered anhydrous aluminium chloride in one lot, and immediately attach a reflux condenser. When the evolution of hydrogen chloride ceases (about 5 minutes), slowly warm the mixture to the boiling point on a water bath. Reflux for 10 minutes with frequent shaking the reaction is then complete. Cool the reaction mixture to 0°, and decompose the aluminium complex by the cautious addition, with shaking, of 100 g. of crushed ice. Then add 25 ml. of concentrated hydrochloric acid, transfer to a 2 htre round-bottomed flask and steam distil, preferably in the apparatus, depicted in Fig. II, 41, 3 since the a-tetralone is only moderately volatile in steam. The carbon disulphide passes over first, then there is a definite break in the distillation, after whieh the a-tetralone distils completely in about 2 htres of distillate. 

CAUTION. The preparation of o-nitrobenzoyl chloride, o-nitrophenacetyl chloride and all o nitroacid chlorides should not be attempted by the above methods a violent explosion may occur upon distilling the product or when the last traces of thionyl chloride are removed in vacuo at 100°. Perhaps the safest method is to treat the pure acid in benzene solution with 1 1 mols of thionyl chloride and to reflux until evolution of sulphur dioxide and hydrogen chloride has ceased the solution of the acid chloride in benzene may then bo employed for most reactions. 

The reduction of acyl halides with hydrogen to form aldehydes using Pd catalyst is well known as the Rosenmund reduction[756]. Some acyl chlorides give decarbonyiation products rather than aldehydes under Rosenmund conditions. The diene 890 was obtained by decarbonyiation in an attempted Rosenmund reduction of acetyloleanolic acid chloride (889)[757], Rosenmund reduction of sterically hindered acyl chlorides such as diphenyl- and tnpheny-lacetyl chloride (891) gives the decarbonylated products 892[758],... 

Thiazole acid chlorides react with diazomethane to give the diazoketone. The later reacts with alcoholic hydrogen chloride to give chloroacetylthiazole (Scheme 16). However, the Wolff rearrangement of the diazoketone is not consistently satisfactory (82). Heated with alcohol in the presence of copper oxide the 5-diazomethylketone (24) gives ethyl 5-thiazoleacetate (25) instead of the expected ethoxymethyl 5-thiazolyl ketone (Scheme 17) (83). 

Sulfur tetrafluoride [7783-60-0] SF, replaces halogen in haloalkanes, haloalkenes, and aryl chlorides, but is only effective (even at elevated temperatures) in the presence of a Lewis acid catalyst. The reagent is most often used in the replacement of carbonyl oxygen with fluorine (15,16). Aldehydes and ketones react readily, particularly if no alpha-hydrogen atoms are present (eg, benzal fluoride [455-31-2] from benzaldehyde), but acids, esters, acid chlorides, and anhydrides are very sluggish. However, these reactions can be catalyzed by Lewis acids (HP, BF, etc). 

Petoxycatboxyhc acids also have been prepared by the reaction of acid chlorides, anhydrides, or boric-catboxyhc anhydrides with hydrogen or sodium peroxide. These reactions ate carried out at low temperature and with excess peroxide to avoid the formation of diacyl peroxides (44,168,181,184). 

Polymeric diacyl peroxides (26) can be prepared from the reaction of dibasic acid chlorides, eg, succinoyl, fumaryl, sebacoyl, and terephthaloyl chlorides, with sodium or hydrogen peroxide (187). 

Cychc diacyl peroxides can be generated from suitable dibasic acid chlorides and sodium or hydrogen peroxide, especially in dilute solutions (187,205), eg, 2,3-ben2odioxin-l,4-dione [4733-52-2] from phthaloyl chloride ... 

The chemistry of benzenecarboxyUc acids generally is the same as that of other carboxyUc acids, which can be converted into esters, salts, acid chlorides, and anhydrides. Each carboxyl group can react separately, so that compounds in which carboxyl groups are converted into different derivatives can be prepared. Because there are aromatic hydrogens available in most of these acids, they also undergo reactions characteristic of the benzene nucleus. Some of the anhydrides have characteristic reactions. 

Because almost any diacid can be leaddy converted to the acid chloride, this reaction is quite versatile and several variations have been developed. In the interfacial polymerization method the reaction occurs at the boundary of two phases one contains a solution of the acid chloride in a water-immiscible solvent and the other is a solution of the diamine in water with an inorganic base and a surfactant (48). In the solution method, only one phase is present, which contains a solution of the diamine and diacid chloride. An organic base is added as an acceptor for the hydrogen chloride produced in the reaction (49). Following any of these methods of preparation, the polymer is exposed to water and the acid chloride end is converted to a carboxyhc acid end. However, it is very difficult to remove all traces of chloride from the polymer, even with repeated washings with a strong base. 

Mixed Halide Alkoxides. Metal chlorides, hydrogen chloride, and carboxyUc acid chlorides convert metal alkoxides to metal chloride alkoxides. 

Isoquinoline can be reduced quantitatively over platinum in acidic media to a mixture of i j -decahydroisoquinoline [2744-08-3] and /n j -decahydroisoquinoline [2744-09-4] (32). Hydrogenation with platinum oxide in strong acid, but under mild conditions, selectively reduces the benzene ring and leads to a 90% yield of 5,6,7,8-tetrahydroisoquinoline [36556-06-6] (32,33). Sodium hydride, in dipolar aprotic solvents like hexamethylphosphoric triamide, reduces isoquinoline in quantitative yield to the sodium adduct [81045-34-3] (25) (152). The adduct reacts with acid chlorides or anhydrides to give N-acyl derivatives which are converted to 4-substituted 1,2-dihydroisoquinolines. Sodium borohydride and carboxylic acids combine to provide a one-step reduction—alkylation (35). Sodium cyanoborohydride reduces isoquinoline under similar conditions without N-alkylation to give... 

Health nd Safety Factors. Thionyl chloride is a reactive acid chloride which can cause severe bums to the skin and eyes and acute respiratory tract injury upon vapor inhalation. The hydrolysis products, ie, hydrogen chloride and sulfur dioxide, are beheved to be the primary irritants. Depending on the extent of inhalation exposure, symptoms can range from coughing to pulmonary edema (182). The LC q (rat, inhalation) is 500 ppm (1 h), the DOT label is Corrosive, Poison, and the OSHA PEL is 1 ppm (183). The safety aspects of lithium batteries (qv) containing thionyl chloride have been reviewed (184,185). 

Chloroformates, especially those of low molecular weight, are lachrimators, vesicants, and produce effects similar to those of hydrogen chloride or carboxyhc acid chlorides. They can also irritate the skin and mucous membranes, producing severe bums and possible irreversible tissue damage. 

Ben zotricbl oride is hydrolyzed to benzoic acid by hot water, concentrated sulfuric acid, or dilute aqueous alkaH. Benzoyl chloride [98-88-4] is produced by the reaction of benzotrichloride with an equimolar amount of water or an equivalent of benzoic acid. The reaction is catalyzed by Lewis acids such as ferric chloride and zinc chloride (25). Reaction of benzotrichloride with other organic acids or with anhydrides yields mixtures of benzoyl chloride and the acid chloride derived from the acid or anhydride (26). Benzo triflu oride [98-08-8] is formed by the reaction of benzotrichloride with anhydrous hydrogen fluoride under both Hquid- and vapor-phase reaction conditions. 

Cyanohydrins react with hydrogen haUdes or PCl to give a-halo nitriles which can be further hydrolyzed to the a-halo carboxyUc acids. The a-hydroxy group of cyanohydrins can be esterified with an acid or acid chloride. Dehydration of cyanohydrins with phosphoms pentoxide gives >80% yields of alkylacrylonitriles (8). 

Condensa.tlon, This term covers all processes, not previously iacluded ia other process definitions, where water or hydrogen chloride is eliminated ia a reaction involving the combination of two or more molecules. The important condensation reactions are nitrogen and sulfur heterocycle formation, amide formation from acid chlorides, formation of substituted diphenyl amines, and misceUaneous cyclizations. 

The reaction of alcohols and acid chlorides in the presence of magnesium has been described (68). With primary and secondary alcohols the reaction is very smooth, and affords high and sometimes quantitative yields. Difficulty esteritiable hydroxy compounds such as tertiary alcohols and phenols can be esteritied by this method. The reaction carried out in ether or benzene is usually very vigorous with evolution of hydrogen. 

Ethers. In the presence of anhydrous agents such as ferric chloride (88), hydrogen bromide, and acid chlorides, ethers react to form esters (see Ethers). Esters can also be prepared from ethers by an oxidative process (89). With mixed sulfonic—carboxyhc anhydrides, ethers are converted to a mixture of the corresponding carboxylate and sulfonate esters (90) ... 

The 4-azidobutyrate ester is introduced via the acid chloride. Gleavage occurs by pyrrolidone formation after the azide is reduced by hydrogenation, H2S or Ph3P. ... 

This method with some slight modihcations is applied in the synthesis of to-bromo esters from Cs to Cn. Methyl 5-bromovalerate has been prepared by treating the silver salt of methyl hydrogen adipate with bromine. The ethyl ester has been prepared from the acid by esterification or through the acid chloride. ... 

As with other groups, halogens can substitute hydrogen in organic compounds containing additional functional moieties such as carboxylic acids to form acid chlorides, e.g. acetyl chloride CH3COCI. These are reactive acidic compounds liberating hydrochloric acid on contact with water. 

Rosenmund reaction is the action between acid chloride and hydrogen in the presence of palladium catalyst to produce aldehydes... 

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