Anions carboxylic acids, esters

Inspired by the many hydrolytically-active metallo enzymes encountered in nature, extensive studies have been performed on so-called metallo micelles. These investigations usually focus on mixed micelles of a common surfactant together with a special chelating surfactant that exhibits a high affinity for transition-metal ions. These aggregates can have remarkable catalytic effects on the hydrolysis of activated carboxylic acid esters, phosphate esters and amides. In these reactions the exact role of the metal ion is not clear and may vary from one system to another. However, there are strong indications that the major function of the metal ion is the coordination of hydroxide anion in the Stem region of the micelle where it is in the proximity of the micelle-bound substrate. The first report of catalysis of a hydrolysis reaction by me tall omi cell es stems from 1978. In the years that... 

Anionic Carboxylic acid salts Sulfuric acid ester salts Good detergency Good wetting agents Generally water-soluble Electrolyte-tolerant Electrolyte-sensitive... 

Polymeric phosphonium salt-bound carboxylate, benzenesulphinate and phenoxide anions have been used in nucleophilic substitution reactions for the synthesis of carboxylic acid esters, sulphones and C/O alkylation of phenols from alkyl halides. The polymeric reagent seems to increase the nucleophilicity of the anions376 and the yields are higher than those for corresponding polymer phase-transfer catalysis (reaction 273). 

Pig Liver Esterase (PLE). This is the more used car-boxylesterase (carboxylic-ester hydrolase, EC 3.1.1.1, CAS 9016-18-6) which physiologically catalyzes the hydrolysis of carboxylic acid esters to the free acid anion and alcohol. PLE is a serine hydrolase which has been widely used for the preparation of chiral synthons and these applications have been fully reviewed. An active-site model for interpreting and predicting the specificity of the enzyme has been published. In the pioneering studies of the enzyme applications field, PLE was used for the chiral synthesis of mevalonolactone. Prochiral 3-substituted glutaric acid diesters... 

Syuthesis of aliphatic carboxylic acids esters, and amides. Sodium tctracarbonyl-ferrate(-ll) (1) reacts with aliphatic halides and tosylatcs to give anionic alkyltetra carbonyliron(O) complexes (2). In the presence of carbon monoxide these undergo... 

A great variety of substances is capable of acting as activators. The first group comprises iV-substituted lactams with polar substituents at the nitrogen. These iV-substituted lactams must be able to acylate lactam anions with opening of the lactam ring of the activator at a rate comparable to the rate of polymerization. The main representatives of this group are acyllactams [84, 89, 107—110] (V), iV-substituted [111] (VI) or iV,Af-disubstituted [112] carbamoyllactams (VII), JV-carboxylic acid esters of lactams [112] (VIII) and salts of lactam-N-carboxylie acids [107] (IX), viz. 

Classically, the acylzirconocene chlorides can be converted into aldehydes, carboxylic acids, esters, and acyl halides. Recendy, the usefulness of acylzirconocenes has been extended. In fact, these unmasked acyl anions directly add to aldehydes and imines affording a-hydroxy or a-amino ketones, respectively. The reaction of acylzirconocene chlorides with imines also proceeds under Bronsted acid-catalyzed conditions, even with aqueous acids. ... 

Two series of new polyphosphazenes were prepared by derivatization of preformed poly(methylphenylphosphazene), [Me(Ph)PN]p. This Involved Initial deprotonatlon of part of the methyl substituents with n-BuLi followed by treatment of the intermediate anion with carbon dioxide or with fluorinated aldehydes or ketones. With appropriate workup procedures, either carboxylic acid, ester, carboxylate salt, or fluorinated alcohol derivatives were obtained. These reactions and the characterization of the products are discussed In this paper. Related derivatization reactions are also discussed. 

Grey RA, Pez GP, Wallo A (1981) Anionic metal hydride catalysts.2. Application to the hydrogenation of ketones, aldehydes, carboxylic-acid esters, and nitriles. J Am Chem Soc 103 7536-7542... 

Initiation of heterocyclic carbon-carbon bond fission by potassium anions Generation of carboxylic acid ester dianions from p-lactones... 

Glycerol ethers, AG-OCH2CH(OH)CHjOH Butyl ethers, AG-OCHjCHjCHjCHj Benzyl ethers, AG-OCH2C5H5 Ethoxylates, AG-O(CH2CH20),H Carboxylic acid esters, AG-OC(=0)(CH2)xH Ethyl carbonates, AG-OC(=0)OC2Hj Anionic alkyl glucoside derivatives Sulfates, AG-OSO3-... 

Among these, carboxylic acid esters have gained importance in the field of wood preservation, because they are of lower volatility and water-solubility, but higher thermal stability than TBTO. From comparison data it can be concluded that the tributyltin (TBT) moiety of the TBT esters determines their antimicrobial effectiveness and also their oral toxicity. This is in line with the fact that the TBT esters tend to dissociate into the hydrated TBT cation and the respective anion. Due to the lower TBT content compared with TBTO greater quantities of TBT carboxylic acid ester therefore have to be used to achieve sufficient antimicrobial effectiveness. 

NaH stirred ca. 45 min. at 65-70° under Ng in excess dimethyl sulfoxide until Hg-evolution is complete, allowed to react with 1 equivalent of ethyl triphenyl-phosphonium bromide, then with 0.85 equivalent of benzophenone 1,1-di-phenyl-l-propene. Y 97.5%.—The reactivity of the methylsulfinyl carbanion (formed by reaction of NaH with dimethyl sulfoxide), which is even more basic than the trityl anion, is sufficient to convert phosphonium salts into ylides thereby permitting a simple and convenient modification of the Wittig reaction. E. J. Gorey and M. Ghaykowsky, Am. Soc. 8A, 866 (1962) / -diketones from carboxylic acid esters and ketones (s. Synth. Meth. 6, 737), sym. ) -diketones, s. J. J. Bloomfield, J. Org. Chem. 27, 2742 (1962). 

Periasamy et at. obtained aldehydes in good yield from poly-cyclic aromatic hydrocarbon radical anions prepared by the addition of sodium to the aromatic hydrocarbon in THF, followed by formylation with carboxylic acid esters or N,N-dialkyformamides. Reactions of sodium naphthalenide, -anthracenide and -phenan-threnide with ethyl formate yielded the corresponding aldehydes. Substituted naphthalenes e.g. acenaphthene and 2-methylnaphthalene are also formylated using A/,A/-dialkylformamides, but in low yields (20% and 26% respectively). 

Methylsulfinyl enolates are more recently developed d -reagents. They are readily prepared from carboxylic esters and dimsyl anion. Methanesulfenic acid can be eliminated thermally after the condensation has taken place. An example is found in Bartlett s Brefeldin synthesis (P.A. Bartlett. 1978). 

The negatively charged oxygen substituent is a powerful electron donor to the carbonyl group Resonance m carboxylate anions is more effective than resonance m carboxylic acids acyl chlorides anhydrides thioesters esters and amides... 

In base the tetrahedral intermediate is formed m a manner analogous to that pro posed for ester saponification Steps 1 and 2 m Figure 20 8 show the formation of the tetrahedral intermediate m the basic hydrolysis of amides In step 3 the basic ammo group of the tetrahedral intermediate abstracts a proton from water and m step 4 the derived ammonium ion dissociates Conversion of the carboxylic acid to its corresponding carboxylate anion m step 5 completes the process and renders the overall reaction irreversible... 

Section 20 17 Like ester hydrolysis amide hydrolysis can be achieved m either aque ous acid or aqueous base The process is irreversible m both media In base the carboxylic acid is converted to the carboxylate anion m acid the amine is protonated to an ammonium ion... 

Step 1 The Boc protected amino acid is anchored to the resin Nucleophilic substitution of the benzylic chloride by the carboxylate anion gives an ester... 

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