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The Dieckmann condensation, where a molecule with two ester groups reacts intramolecularly, forming a cyclic β-keto ester. In this case, the ring formed must not be strained, usually a 5- or 6-membered chain or ring. Retro-Claisen condensation is the reverse of the title reaction, i.e., the base-induced cleavage of 2-ketoesters
The enzyme undergoes a conformational change upon binding of the oxaloacetate ligand, whereby the active site cleft closes over in order to form the acetyl-CoA binding site. [1] The energy required for domain closure comes from the interaction of the enzyme with the substrate .
All thiolases, whether they are biosynthetic or degradative in vivo, preferentially catalyze the degradation of 3-ketoacyl-CoA to form acetyl-CoA and a shortened acyl-CoA species, but are also capable of catalyzing the reverse Claisen condensation reaction (reflecting the negative Gibbs energy change of the degradation, which is independent of ...
His 337 is also used for the condensation activity, specifically the stabilization of the negative charge on the malonyl thioester carbonyl in the transition state. His303 is used to accelerate catalysis by deprotonating the water molecule to allow for a nucleophilic attack on malonate, thereby releasing bicarbonate.
The reaction is known as the Claisen reaction and was described by Claisen for the first time in 1890. Discovered the thermally induced rearrangement of allyl phenyl ether in 1912. He details its reaction mechanism in his last scientific publication (1925). In his honor, the reaction has been named the Claisen rearrangement.
Michael addition, Michael system; Michael condensation; Michaelis–Arbuzov reaction; Midland Alpine borane reduction; Mignonac reaction; Milas hydroxylation of olefins; Minisci reaction; Mislow–Evans rearrangement; Mitsunobu reaction; Miyaura borylation; Modified Wittig-Claisen tandem reaction; Molisch's test; Mozingo reduction
Oxaloacetic acid (also known as oxalacetic acid or OAA) is a crystalline organic compound with the chemical formula HO 2 CC(O)CH 2 CO 2 H. Oxaloacetic acid, in the form of its conjugate base oxaloacetate, is a metabolic intermediate in many processes that occur in animals.
The ACP-bound elongation group reacts in a Claisen condensation with the KS-bound polyketide chain under CO 2 evolution, leaving a free KS domain and an ACP-bound elongated polyketide chain. The reaction takes place at the KS n -bound end of the chain, so that the chain moves out one position and the elongation group becomes the new bound group.