Esters general formula

Esters - general formula R-COO-R, where R is an alkyl group... 

Note also that if another ester, of general formula R-COOCjHj, were used in place of benzaldehyde in the above reaction, a similar complex would be formed, and on acidification would give an unstable p-hydroxy-P-ethoxy ester, which would very readily lose ethanol with the formation of a 3-keto-ester. 

The formation of acyloins (a-hydroxyketones of the general formula RCH(OH)COR, where R is an aliphatic residue) proceeds best by reaction between finely-divided sodium (2 atoms) and esters of aliphatic acids (1 mol) in anhydrous ether or in anhydrous benzene with exclusion of oxygen salts of enediols are produced, which are converted by hydrolysis into acyloins. The yield of acetoin from ethyl acetate is low (ca. 23 per cent, in ether) owing to the accompanying acetoacetic ester condensation the latter reaction is favoured when the ester is used as the solvent. Ethyl propionate and ethyl ji-butyrate give yields of 52 per cent, of propionoin and 72 per cent, of butyroin respectively in ether. 

Phosphate Esters. A variety of phosphate esters are used as synthetic lubricants, particularly because of their good fire resistance. They have the general formula OP(OR)2, where R may represent a variety of aryl or alkyl hydrocarbon groups containing four or more carbon atoms to give three broad classes triaryl, trialkyl, and aryl alkyl phosphates (37,38). 

Besides direct hydrolysis, heterometaHic oxoalkoxides may be produced by ester elimination from a mixture of a metal alkoxide and the acetate of another metal. In addition to their use in the preparation of ceramic materials, bimetallic oxoalkoxides having the general formula (RO) MOM OM(OR) where M is Ti or Al, is a bivalent metal (such as Mn, Co, Ni, and Zn), is 3 or 4, and R is Pr or Bu, are being evaluated as catalysts for polymerization of heterocychc monomers, such as lactones, oxiranes, and epoxides. An excellent review of metal oxoalkoxides has been pubUshed (571). 

The general formula for boric acid esters is B(OR)2. The lower molecular weight esters such as methyl, ethyl, and phenyl are most commonly referred to as methyl borate [121 -43-7] ethyl borate [130-46-9J, and phenyl borate [1095-03-0] respectively. Some of the most common boric acid esters used in industrial appHcations are Hsted in Table 1. The nomenclature in the boric acid ester series can be confusing. The lUPAC committee on boron chemistry has suggested using trialkoxy- and triaryloxyboranes (5) for compounds usually referred to as boric acid esters, trialkyl (or aryl) borates, trialkyl (or aryl) orthoborates, alkyl (or aryl) borates, alkyl (or aryl) orthoborates, and in the older Hterature as boron alkoxides and aryloxides. CycHc boric acid esters, which are trimeric derivatives of metaboric acid (HBO2), are known as boroxines (1). 

The esters are a group of compounds with the general formula R-C-O-O-R. They are not generally classified as hazardous materials, except for the acrylates, which are monomers and highly flammable. Few of the rest of the class are flammable. There are some esters that are hazardous. 

Ethylmalonic Acid.—Like acetoacetic ester (see p. 83), diethylmalonate contains the gioup CO.CHj.CO. By the action of sodium or sodium alroholate, the hydrogen atoms of the methylene group are successively replaceable by sodium. The sodium atoms are in turn replaceable by alkyl or acyl groups. Thus, in the present preparation, ethyl malonic ester is obtained by the action of ethyl iodide on the monosodium compound. If this substance be treated with a second molecule of sodium alcoholate and a second molecule of alkyl iodide, a second radical would be in roduced, and a compound formed of the general formula... 

Nitrostarch (NS) is a nitrate ester (more properly a mixt of several nitrate esters) of starch, which is a plant-product polysaccharide of the general formula (CgHujOj) The general molecular formula for NS is [C6H7(OH)x-(0NO2)y]n where x + y - 3, The following empirical relation, similar to that used for NC... 

A dissertation from 1943 [2] describes an interesting investigation concerning synthesis and properties of pure ether carboxylates. With metallic sodium and chloroacetic acid ethyl ester followed by saponification, ether carboxylates were made with the general formula... 

From both economic and ecological points of view, substances derived from esters of monocarboxylic acids sulfonated in the a position form an interesting class of surfactants [1]. The general formula of these a-sulfomonocarboxylic esters, also called a-sulfo fatty acid esters or, in short, a-ester sulfonates, is Rj-CH(S03Me)-C00-R2 (with Rj and R2 = alkyl groups, Me = alkali metal). 

Write the general formula of each of the following types of compounds, using R to denote an organic group (a) ether (b) ketone (c) ester (d) amide. 

Acetylsalicylic acid is an example of an ester, a class of organic compounds with the general formula RCOOR. Esters contain an ester linkage consisting of a carbonyl group to which an alkyl group (R) and an alkoxy group (OR ) are bonded (Fig. 13.4.1). Under either acidic or basic conditions or in the presence... 

We see from the above that there is a striking alternation in the physiological properties of w-fluorocarboxylic esters of the general formula of F- [CH2]w-C02.R. Thus when n is an odd number the compound is highly toxic to animals, whereas when n is even the compound is non-toxic. All the toxic compounds are powerful convulsant poisons and showed symptoms of the fluoroacetate type. 

To rationalize the stereospecificity of PLE toward a large variety of monocarboxylic and dicarboxylic esters, Tamm and co-workers have proposed the general formula displayed in Fig. 7.5 [5 5] [67]. Here, no representation of the active site is implied, but the model does rationalize numerous data and allows some qualitative predictions. A qualitative topographical model of the active site of PLE has been proposed by Jones and co-workers [68] [69], As shown in Fig. 7.6, substrate binding is defined by a carboxylate group that interacts with the catalytic serine residue, and by one or two hydrophobic groups that bind to sites 1 and/or 2. 

Fig. 7.5. General formula summarizing the structural and stereochemical requirements, which an ester should meet to fit into the active site of pig liver esterase. A nucleophilic attack by the serine OH group seemingly occurs from this side B no or only small substituents allowed here C groups of small to medium size allowed in this area D space allowed in these areas for carbon chains, with polar substituents (e.g., another ester group) preferred in the upper part ...

Carbonic acid esters (alkoxycarbonyl derivatives) are diesters of general formula R-O-CO-O-R. A single mechanism operates in the HO -catalyzed (and presumably also in the enzyme-catalyzed) hydrolysis of carbonic acid esters, namely a rate-determining addition of the base to the carbonyl C-atom to form an intermediate whose breakdown yields the drug (ROH), C02, and an alcohol (R OH) (Fig. 8.7,a) [153],... 

AT-[(Acyloxy)methyl] derivatives of active amines and amides have the general formula RK N-CHR O-COR " where R" = H or Me (or an even larger substituent) and COR" is the acyl group. Activation of these derivatives occurs in two steps as depicted in Fig. 8.20, by analogy with the biotransformation of 0-[(acyloxy)methyl] derivatives of phenols (Sect. 8.5.6) [62], The first step is enzymatic or nonenzymatic cleavage of the ester bridge (Fig. 8.20,a), followed by chemical breakdown of the A-(hydroxymethyl) intermediate (see also Chapt. 5 in [81]). Here, again, liberation of toxic formaldehyde, i. e., where R" = H, should be avoided whenever possible by substitution of, e.g., Me at R"... 

The general formula for an ester is RCOOR, where R is a hydrogen atom or a hydrocarbon, and R is a hydrocarbon. You can think of an ester as the product of a reaction between a carboxylic acid and an alcohol, as shown in Figure 1.26. 

Parathion, a heavily-used pesticide with strongly adverse environmental effects, is a member of the phosphoric acid esters group with a general formula of the type... 

Compounds of the general formula 69 are prepared by cycloaddition of N-methyl- or A(-arylmaleimides with arylidene imines of AAs and in the presence of an aromatic aldehyde. Stabilized azomethine ylides are formed as intermediates, which then afford the cycloadducts. Several isomers are formed, and the influence of various metal salts and solvents was investigated (87BCJ4067 88T557). Similar transformations have been performed with A-ailyl glycine esters (91TL1359). 

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