Acylation ester synthesis

Benzimidazole-2-carboxylic acid decarboxylation, 5, 435 Benzimidazole-3-carboxylic acid, 1-hydroxy-ethyl ester synthesis, 6, 407 Benzimidazoles acidity, 5, 50, 385, 386 acylation, 5, 71, 391, 402, 417 2V-alkyl-... 

Pyrazolo[l,5-a]pyridine-2,3-dicarboxylic acid dimethyl ester synthesis, 5, 153 Pyrazolopyridines acylation, 5, 311 6-fused... 

Among other methods for the preparation of alkylated ketones are (1) the Stork enamine reaction (12-18), (2) the acetoacetic ester synthesis (10-104), (3) alkylation of p-keto sulfones or sulfoxides (10-104), (4) acylation of CH3SOCH2 followed by reductive cleavage (10-119), (5) treatment of a-halo ketones with lithium dialkyl-copper reagents (10-94), and (6) treatment of a-halo ketones with trialkylboranes (10-109). 

Much more important than these reactions, however, are the reactions of CDI and its analogues with carboxylic acids, leading to AAacylazoles, from which (by acyl transfer) esters, amides, peptides, hydrazides, hydroxamic acids, as well as anhydrides and various C-acylation products may be obtained. The potential of these and other reactions will be shown in the following chapters. In most of these reactions it is not necessary to isolate the intermediate AAacylazoles. Instead, in the normal procedure the appropriate nucleophile reactant (an alcohol in the ester synthesis, or an amino acid in the peptide synthesis) is added to a solution of an AAacylimidazole, formed by reaction of a carboxylic acid with CDI. Thus, CDI and its analogues offer an especially convenient vehicle for activation of... 

Malonic ester synthesis, 7 acylation by o-nitrobenzoyl chloride, 70... 

Biosynthesis of cholesteryl esters. The acyl-CoA cholesterol acyltransferase involved in cholesteryl ester synthesis is located on the cytosolic surface of liver endoplasmic reticulum. 

H- Benzimidazole, 2,2-pentamethylene-reduction, 5, 423 Benzimidazole-2-carbaldehyde oximes, 5, 436 Benzimidazolecarbaldehydes oxidation, 5, 437 Benzimidazole-2-carbamates 5-substituted as anthelmintics, I, 202 Benzimidazole-l-carboxylic acid, 2-amino-methyl ester reactions, 5, 453 Benzimidazole-2-carboxylic acid decarboxylation, 5, 435 Benzimidazole-3-carboxylic acid, 1-hydroxy-ethyl ester synthesis, 6, 407 Benzimidazoles acidity, 5, 50, 385, 386 acylation, 5, 71, 391, 402, 417 N-alkyl-... 

Ikushima et al. (1996) Batch Ester synthesis from acyl donors and terpene alcohols Lipase from Candida cylindracea... 

Malonic ester, ethoxymagnesium derivative, solution of, 30, 70 Malonic ester synthesis, 30, 7 acylation by o-nitrobenzoyl chloride, 30, 70... 

Fig. 4. Effect of alcohol chain length on ester synthesis catalyzed by POS-P VA lipase. Reactions were performed at 37°C for 24 h using caprylic acid as acyl donor.

A few words about HDL these lipoproteins are synthesized largely by the liver. They act as ApoE, ApoC, and ApoA traffickers, but in addition, they also serve as a factory for the synthesis of cholesterol esters. HDL may absorb free cholesterol from various peripheral tissues, including arteries. Cholesterol is then converted to a large extent to fatty acyl esters by the action of the enzyme lecithin-cholesterol acyltransferase [LCAT see Equation 19.2)]. LCAT is activated by ApoA-I. Inactive LCAT is a plasma component. 

Many alkylation and acylation reactions are most effective using anions of /3-dicarbonyl compounds that can be completely deprotonated and converted to their enolate ions by common bases such as alkoxide ions. The malonic ester synthesis and the acetoacetic ester synthesis use the enhanced acidity of the a protons in malonic ester and acetoacetic ester to accomplish alkylations and acylations that are difficult or impossible with simple esters. 

The malonic ester synthesis makes substituted derivatives of acetic acid. Malonic ester (diethyl malonate) is alkylated or acylated on the more acidic carbon that is a to both carbonyl groups, and the resulting derivative is hydrolyzed and allowed to decarboxylate. 

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