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In the absence of metal catalysts, decarbonylation (vs decarboxylation) is rarely observed in organic chemistry. One exception is the decarbonylation of formic acid: H CO OH → CO + H 2 O. The reaction is induced by sulfuric acid, which functions as both a catalyst and a dehydrating agent.
Thus, synthesis of benzaldehyde through the Friedel–Crafts pathway requires that formyl chloride be synthesized in situ. This is accomplished by the Gattermann-Koch reaction, accomplished by treating benzene with carbon monoxide and hydrogen chloride under high pressure, catalyzed by a mixture of aluminium chloride and cuprous chloride ...
The decarboxylation of this compound by heat is essential for the psychoactive effect of smoked cannabis, and depends on conversion of the enol to a keto group when the alpha carbon is protonated. Upon heating, Δ9-tetrahydrocannabinolic acid decarboxylates to give the psychoactive compound Δ9- Tetrahydrocannabinol . [ 13 ]
The term stems from cumene (isopropyl benzene), the intermediate material during the process. It was invented by R. Ūdris and P. Sergeyev in 1942 (USSR), [1] and independently by Heinrich Hock in 1944. [2] [3] This process converts two relatively cheap starting materials, benzene and propylene, into two more valuable ones, phenol and acetone.
Lipoic acid (LA), also known as α-lipoic acid, alpha-lipoic acid (ALA) and thioctic acid, is an organosulfur compound derived from caprylic acid (octanoic acid). [3] ALA, which is made in animals normally, is essential for aerobic metabolism. It is also available as a dietary supplement or pharmaceutical drug in some countries.
The alpha-ketol rearrangement is an interconversion of a hydroxyl alpha to a carbonyl to the complementary carbonyl and hydroxyl groups, with migration of a substituent. It is mechanistically equivalent to the benzyllic acid rearrangement at the point after the nucleophile attacks the 1,2-dicarbonyl.
The reaction product is a derivative of benzene. Scheme 1. Bergman cyclization. The reaction proceeds by a thermal reaction or pyrolysis (above 200 °C) forming a short-lived and very reactive para-benzyne biradical species. It will react with any hydrogen donor such as 1,4-cyclohexadiene which converts to benzene.
The Hammick reaction, named after Dalziel Hammick, is a chemical reaction in which the thermal decarboxylation of α-picolinic (or related) acids in the presence of carbonyl compounds forms 2-pyridyl-carbinols. [1] [2] [3] The Hammick reaction. Using p-cymene as solvent has been shown to increase yields. [4]