Acyl chlorides, reactions

Note the use of a weak base to scavenge the HCl formed as a by-product in the acyl chloride reaction. The aromatic base pyridine is often used for this purpose, though it has other useful attributes. It functions as a good solvent for the reaction, but it... 

Final purification by use of metal complexes was also applied in the syntheses of the ligands XS4—H4. These ligands exclusively contain thiolate donors and were prepared by Hahn et al. (23) using 2,3-dimercaptobenzoic acid as starting material (Scheme 8). Isopropyl or benzyl protection of the thiol functions, conversion into the acyl chlorides, reaction with a,oo-diamines, and deprotection of the sulfur atoms enabled the connection of two 1,2-benzene-dithiol units via carboxylic acid amide bonds. 

In the case of acyl chlorides, reaction with the Lewis acid generates an electrophilic acylium ion. These species show no tendency to rearrange (Scheme 3.4). Again, it is questionable whether a free cation is formed or if a complex between the acyl group and AICI3 is the attacking species. 

The difference in the rate at which the reaction takes place in the two cases is marked. In the case of the acyl chloride reaction takes place when the two substances are brought together at room temperature. It will be recalled, on the other hand, that in the preparation of amines by this reaction the alkyl halide is heated with ammonia at a high temperature to bring about the reaction. The introduction of a negative radical into ammonia is thus much more readily accomplished than the introduction of a positive radical. 

The most likely product of an acyl chloride reaction with ammonia is ... 

Oxidation, esterification/ amidation Carboxylated groups -OH, -NHj groups 1) Activation via formation of acyl-chloride reaction with SOClj usually in DMF, high temperatures 2) Activation via aqueous solution of EDC/DCC and NHS or HOBt, mild conditions Electrochemical biosensing Immobilization of proteins, DNA, and antibodies [54, 55]... 

When acyl chlorides react with alcohols and phenol, we get esters (and HCl) formed. The reactions happen more quickly than the reactions of alcohols or phenol with carboxylic acids. The acyl chloride reactions also go to completion and do not form an equilibrium mixture. Therefore they are useful in the synthesis of esters in the chemical industry. 

Several helical polycyclic hydrocarbons bearing aryl substituents in the most hindered positions were synthesized in this way. The starting material 2-benzo[c]phenanthrenyl-rerr-butylketone 3.601 was prepared as follows (Scheme 3.50) [279]. Treatment of 2-benzo[c]phenanthrene-2-carboxylic acid 3.600 with thionyl chloride formed the corresponding acyl chloride. Reaction of the latter with er -butyl copper (obtained... 

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