Decarboxylation

About: Decarboxylation is a research topic. Over the lifetime, 9914 publications have been published within this topic receiving 193955 citations. The topic is also known as: decarboxylation reaction.

Visible-Light-Induced Decarboxylative Functionalization of Carboxylic Acids and Their Derivatives

Abstract: Visible-light-induced radical decarboxylative functionalization of carboxylic acids and their derivatives has recently received considerable attention as a novel and efficient method to create CC and CX bonds. Generally, this visible-light-promoted decarboxylation process can smoothly occur under mild reaction conditions with a broad range of substrates and an excellent functional-group tolerance. The radical species formed from the decarboxylation step can participate in not only single photocatalytic transformations, but also dual-catalytic cross-coupling reactions by combining photoredox catalysis with other catalytic processes. Recent advances in this research area are discussed herein.

In‐Vivo Decarboxylation of α‐Methyl DOPA and α‐Methyl Metatyrosine

Abstract: α-Methyl DOPA (DOPA = 3,4-dihydroxyphenylalanine) and α-methyl metatyrosine were injected to mice (400 mg/kg intraperitoneally). The former amino acid was also injected to rabbits (200 mg/kg intravenously). At varying intervals after the injection the brains were examined for monoamines (5-hydroxytryptamine, noradrenaline, dopamine, and α-methyl analogues). A transient decrease in 5-hydroxytryptamine and dopamine and a prolonged and more marked decrease in noradrenaline were observed. The α-methyl amino acids were found to undergo decarboxylation and subsequent β-hydroxylation in vivo. The drop in noradrenaline and dopamine levels in brain caused by the α-methyl amino acids appears to be largely due to displacement by these decarboxylation products, which may possibly also take over the functions of the physiological amines.

Rhodium- and iridium-catalyzed oxidative coupling of benzoic acids with alkynes via regioselective C-H bond cleavage.

Abstract: The oxidative coupling of benzoic acids with internal alkynes effectively proceeds in the presence of [Cp*RhCl2]2 and Cu(OAc)2 x H2O as catalyst and oxidant, respectively, to produce the corresponding isocoumarin derivatives. The copper salt can be reduced to a catalytic quantity under air. Interestingly, by using [Cp*IrCl2]2 in place of [Cp*RhCl2]2, the substrates undergo 1:2 coupling accompanied by decarboxylation to afford naphthalene derivatives exclusively. In this case, Ag2CO3 acts as an effective oxidant.

Why asparagine needs carbohydrates to generate acrylamide.

Abstract: Structural considerations dictate that asparagine alone may be converted thermally into acrylamide through decarboxylation and deamination reactions. However, the main product of the thermal decomposition of asparagine was maleimide, mainly due to the fast intramolecular cyclization reaction that prevents the formation of acrylamide. On the other hand, asparagine, in the presence of reducing sugars, was able to generate acrylamide in addition to maleimide. Model reactions were performed using FTIR analysis, and labeling studies were carried out using pyrolysis-GC/MS as an integrated reaction, separation, and identification system to investigate the role of reducing sugars. The data have indicated that a decarboxylated Amadori product of asparagine with reducing sugars is the key precursor of acrylamide. Furthermore, the decarboxylated Amadori product can be formed under mild conditions through the intramolecular cyclization of the initial Schiff base and formation of oxazolidin-5-one. The low-energy decarboxylation of this intermediate makes it possible to bypass the cyclization reaction, which is in competition with thermally induced decarboxylation, and hence promote the formation of acrylamide in carbohydrate/asparagine mixtures. Although the decarboxylated Amadori compound can be formed under mild conditions, it requires elevated temperatures to cleave the carbon-nitrogen covalent bond and produce acrylamide.