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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 ]
Sodium hypochlorite, [4] lead tetraacetate, [5] N-bromosuccinimide, and (bis(trifluoroacetoxy)iodo)benzene [6] can effect a Hofmann rearrangement. The intermediate isocyanate can be trapped with various nucleophiles to form stable carbamates or other products rather than undergoing decarboxylation.
DDQ and an acid catalyst has been used to synthesise a steroid with a phenanthrene core by oxidation accompanied by a double methyl migration. [9] In the process, DDQ is itself reduced into an aromatic hydroquinone product. Sulfur and selenium are traditionally used in aromatization, the leaving group being hydrogen sulfide. [10]
The benzilic acid rearrangement is formally the 1,2-rearrangement of 1,2-diketones to form α-hydroxy–carboxylic acids using a base. This reaction receives its name from the reaction of benzil with potassium hydroxide to form benzilic acid. First performed by Justus von Liebig in 1838, [1] it is the first reported example of a rearrangement ...
Dehydration may be accompanied by decarboxylation when an activated carboxyl group is present. The aldol addition product can be dehydrated via two mechanisms; a strong base like potassium t -butoxide , potassium hydroxide or sodium hydride deprotonates the product to an enolate , which eliminates via the E1cB mechanism , [ 9 ] [ 10 ] while ...
The carbons alpha to carbonyl groups can be deprotonated by a strong base. The carbanion formed can undergo nucleophilic substitution on the alkyl halide, to give the alkylated compound. On heating, the di-ester undergoes thermal decarboxylation , yielding an acetic acid substituted by the appropriate R group. [ 1 ]
The original Knorr synthesis employed two equivalents of ethyl acetoacetate, one of which was converted to ethyl 2-oximinoacetoacetate by dissolving it in glacial acetic acid, and slowly adding one equivalent of saturated aqueous sodium nitrite, under external cooling. Zinc dust was then stirred in, reducing the oxime group to the amine. This ...
In the Curtius rearrangement, sodium azide and an acyl chloride are combined to quantitatively generate the acyl azide intermediate, and the rest of the reaction takes place under neutral conditions.) The carboxylic acid Schmidt reaction starts with acylium ion 1 obtained from protonation and loss of water.