Acyl Halides and Anhydrides

Give a systematic name for each of the following compounds (a) 

For acetyl chloride, CH3C(=0)C1, generate an orbital representation. Label bonds as a or %, and state which orbitals were used to make them (s, p, sp, sp, sp ). Mark empty orbitals and lone pairs, and state their type. 

For each of the following pairs of molecules, predict which would have the higher boiling point, giving your reason  

13(a) The numbering of the benzene ring starts at the carbon bearing the acid chloride group and goes counterclockwise so that the substituents are on the lowest-numbered atoms, hence 4-methoxy-3-methylbenzoyl chloride. 

15(a) Butanoic acid—molecules are held together by strong hydrogen bonds. 

---

The formulated mechanism is supported by the finding that no halogen from the phosphorus trihalide is transferred to the a-carbon of the carboxylic acid. For instance, the reaction of a carboxylic acid with phosphorus tribromide and chlorine yields exclusively an a-chlorinated carboxylic acid. In addition, carboxylic acid derivatives that enolize easily—e.g. acyl halides and anhydrides—do react without a catalyst present. 

All carboxylic acid derivatives are hydrolysed to carboxylic acids by the action of water as nucleophile. Acyl halides and anhydrides of low molecular weight are hydrolysed quite vigorously. Esters and amides react much more slowly, and hydrolysis normally requires acid or base catalysis. This is nicely... 

Acyl halides and anhydrides are the most reactive class of carboxylic acid derivatives, and readily react with amines to give amides. It should be noted that in both cases the leaving group is a conjugate base that, upon protonation during the reaction, will become an... 

Just as pyridine is a weaker base than piperidine, it is also a poorer nucleophile. Nevertheless, it reacts with electrophiles to form stable pyridinium salts. In the examples shown, primary alkyl halides form N-alkylpyridinium salts, whereas acyl halides and anhydrides react to give N-acylpyridinium salts. 

Both acyl halides and anhydrides react with water (hydrolysis). Acyl halides react to form one mole of the carboxylic acid and one mole of the hydrohalic acid, HX. Anhydrides react to form two moles of carboxylic acid. 

Acyl halides and anhydrides are important reactants for the formation of other carbonyl compounds, but you don t need to take up valuable brain space with information about any other acyl halide or anhydride reactions at this time. 

Acylation of RMnI (10, 290).1 Acylating agents such as acyl halides and anhydrides react with RMnI to form ketones in high yield. This reaction can be used to provide acetoxy ketones, keto esters, keto nitriles, and diketones in generally high yield. 

Treatment of A and B with hydrogen over a nickel catalyst results in quantitative conversion of each compound to ferf-butyl alcohol. A reacts with acyl halides and anhydrides, whereas B is unaffected by these reagents. Treatment of 1 mole of A with excess methylmagnesium iodide in diethyl ether solution produces 1 mole of methane and 1 moie each of ferf-butyl alcohol and methanol. One mole of B with excess methylmagnesium iodide produces 1 mole of 2-methoxy-2-methylpropene and 1 mole of ferf-butyl alcohol. 

However, acyl halides and anhydrides usually hydrolyze rapidly without the aid of an acidic or basic catalyst, when in solution. It is important to recognize that an insoluble acyl halide or anhydride often reacts slowly with water. 

The catalyst most commonly used with acyl halides and anhydrides is aluminum chloride ... 

Although hydrolysis of acyl halides and anhydrides is infrequently used in the preparation of acids, several important examples are noted. The acyl chlorides, ArjC = CHCOCl, from the action of oxalyl chloride on di-arylethylenes are hydrolyzed to yS,yS-diarylacrylic acids by stirring with ice-cold sodium carbonate solution. a-Halo acids prepared by the Hell-Volhard-Zelinsky reaction are obtained from the a-halo acid halide by stirring with cold water (method 67). 

Triazoles can be acylated in the usual manner, e.g. with acyl halides and anhydrides. Isocyanates react with the formation of mixed ureas (139), which show characteristic short-wave carbonyl absorptions (1745, 1788 cm ) (61LA(648)72). Treatment of 1,2,3-triazole with thiobenzoyl chloride in the presence of triethylamine yields a mixture of 1-thiobenzoyl-lH- and 2-thiobenzoyl-2//-l,2,3-triazoles (73LA636). 

Introduction. The general methods for the preparation of amides are (1) ammonolysis of esters, acyl halides, and anhydrides (2) the dehydration of the ammonium salts of carboxylic acids ... 

The basic media exceptions can be easily understood if we invoke HSAB theory and realize that the kinetic and thermodynamic products are different. As L becomes a poorer donor, the partial plus on the acyl carbon increases, making it harder. Acylation on the heteroatom of the allylic source is fast for acyl halides and anhydrides where the acyl carbon is harder (greater partial plus) than the acyl carbon of esters. If the reaction is under kinetic control (allylic source added to an excess of acyl halide or anhydride), the Z-acylated product is formed however, if equilibration occurs (excess of allylic source), the product will be the C-acylated, thermodynamic product. 

Acylation. The acylation of soybean proteins with various acyl halides and anhydrides of low and high molecular weight was initially evaluated for its impact on properties of industrial value such as viscosity in dispersion, adhesion, foaming, and detergency (21, 23, 24, 38). 

Reaction 3 is a general example of a ligand substitution reaction with an electrophile, EL (71, 72). Acids, acyl halides, and anhydrides have been shown to undergo Reaction 3, generating substitution products in solution. Reactions with the latter two... 

---