Caproic acid reduction

In the manufacture of hexylresorcinol, resorcinol and caproic acid are heated with a condensing agent, such as zinc chloride, and the intermediate ketone derivative is formed, which is purified by vacuum distillation. After reduction with zinc amalgam and hydrochloric acid, impure hexylresorcinol is formed, which can be purified by vacuum distillation. 

Reduction of the ACP-bound acetoacetate yields D-jff-hydroxybutyryl-ACP from which croto-nyl-ACP is formed by the elimination of water. By the subsequent reduction butyryl-ACP is obtained from which the butyryl residue is transferred to CoA, releasing the SH-group of panto-theine which again reacts with a molecule of malonyl CoA. Butyryl CoA, like acetyl CoA, may react with the peripheral, acyl-binding SH-group of the synthase and subsequently with the malonyl residue. In the following reactions caproic acid is formed from which caprylic, capric, lauric, myristic, palmitic, stearic, and arachidonic acid (Table 26) are formed. The specificity of the enzymes involved as well as other factors such as compartmentalization, stop chain elongation at about 10-20 C-atoms. 

Another interesting coupling reaction reacted acrolein with pyran 1.272 to give 2-hydroxyl-6-aminohexanoic acid (a-hydroxy-e-amino caproic acid, 1.273), after reductive amination of the initial product.157... 

Preparation from 3-bromo-2-hydroxy-6-methyl-5-iso-propylbenzophenone (SMI) by reductive removal of bromine with copper powder in caproic acid at 220° for 15 min (83%) [698]. SMI was obtained from p-thymol by a three-step synthesis (bromi-nation, esterification and Fries rearrangement with titanium tetrachloride). 

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