Acid esters from diesters

Phosphonic acid esters from phosphorous acid diesters (RO)2P(0)H - (R0)2P(0)R from Na-salt cf. 4, 604 electrochemical method s. V.A. Petrosyan, M.E. Niyazym-betov, Izv. Akad. Nauk SSSR Ser. Khim. 1988, 1945. 

Sulfur in oxidation state IV can be used to produce a variety of anionic snUbnates, as depicted in Scheme 1.5. Sodium bisulfite can be used to prepare sulfonates of a,b-unsaturated acids and esters, such as those prepared from maleic anhydride. The mechanism involves Michael addition to the activated double bond by the more nucleophilic sulfur atom, and is conducted in an aqueous two-phase system where, for example, a maleate half acid ester or diester is dispersed and heated under narrowly controlled pH conditions to minimize ester hydrolysis and avoid competitive hydroxide addition to the double bond. The resulting classes of surfactants include sulfosuccinates (which are in fact carboxylate sulfonate disalt surfactants) prepared from the maleic half acid esters of fatty alcohols or alcohol ethoxylates. Diesters of maleic are sulfonated by the same type of process to produce surfactants such as the ubiquitous dioctyl sulfosuccinate (DOSS) from the diester of 2-ethylhexyl alcohol and maleic anhydride. 

Diboric acid esters from boric acid diesters s. 16,169... 

Perhaps the most extensively studied catalytic reaction in acpreous solutions is the metal-ion catalysed hydrolysis of carboxylate esters, phosphate esters , phosphate diesters, amides and nittiles". Inspired by hydrolytic metalloenzymes, a multitude of different metal-ion complexes have been prepared and analysed with respect to their hydrolytic activity. Unfortunately, the exact mechanism by which these complexes operate is not completely clarified. The most important role of the catalyst is coordination of a hydroxide ion that is acting as a nucleophile. The extent of activation of tire substrate througji coordination to the Lewis-acidic metal centre is still unclear and probably varies from one substrate to another. For monodentate substrates this interaction is not very efficient. Only a few quantitative studies have been published. Chan et al. reported an equilibrium constant for coordination of the amide carbonyl group of... 

Diester/Ether Diol of Tetrabromophthalic Anhydride. This material [77098-07-8] is prepared from TBPA in a two-step reaction. First TBPA reacts with diethylene glycol to produce an acid ester. The acid ester and propylene oxide then react to give a diester. The final product, a triol having two primary and one secondary hydroxyl group, is used exclusively as a flame retardant for rigid polyurethane foam (53,54). 

Carboxylic acid hydiazides are prepared from aqueous hydrazine and tfie carboxylic acid, ester, amide, anhydride, or halide. The reaction usually goes poody with the free acid. Esters are generally satisfactory. Acyl halides are particularly reactive, even at room temperature, and form the diacyl derivatives (22), which easily undergo thermal dehydration to 1,3,4-oxadiazoles (23). Diesters give dihydtazides (24) and polyesters such as polyacrylates yield a polyhydrazide (25). The chemistry of carboxyhc hydrazides has been reviewed (83,84). 

Hydrochloric acid [7647-01-0], which is formed as by-product from unreacted chloroacetic acid, is fed into an absorption column. After the addition of acid and alcohol is complete, the mixture is heated at reflux for 6—8 h, whereby the intermediate malonic acid ester monoamide is hydroly2ed to a dialkyl malonate. The pure ester is obtained from the mixture of cmde esters by extraction with ben2ene [71-43-2], toluene [108-88-3], or xylene [1330-20-7]. The organic phase is washed with dilute sodium hydroxide [1310-73-2] to remove small amounts of the monoester. The diester is then separated from solvent by distillation at atmospheric pressure, and the malonic ester obtained by redistillation under vacuum as a colorless Hquid with a minimum assay of 99%. The aqueous phase contains considerable amounts of mineral acid and salts and must be treated before being fed to the waste treatment plant. The process is suitable for both the dimethyl and diethyl esters. The yield based on sodium chloroacetate is 75—85%. Various low molecular mass hydrocarbons, some of them partially chlorinated, are formed as by-products. Although a relatively simple plant is sufficient for the reaction itself, a si2eable investment is required for treatment of the wastewater and exhaust gas. 

Uses. Phthabc anhydride is used mainly in plasticizers, unsaturated polyesters, and alkyd resins (qv). PhthaUc plasticizers consume 54% of the phthahc anhydride in the United States (33). The plasticizers (qv) are used mainly with poly(vinyl chloride) to produce flexible sheet such as wallpaper and upholstery fabric from normally rigid polymers. The plasticizers are of two types diesters of the same monohydric alcohol such as dibutyl phthalate, or mixed esters of two monohydric alcohols. The largest-volume plasticizer is di(2-ethylhexyl) phthalate [117-81-7] which is known commercially as dioctyl phthalate (DOP) and is the base to which other plasticizers are compared. The important phthahc acid esters and thek physical properties are Hsted in Table 12. The demand for phthahc acid in plasticizers is naturally tied to the growth of the flexible poly(vinyl chloride) market which is large and has been growing steadily. 

When a mixture of phosphoric acid and phosphoric acid esters is titrated with a sodium hydroxide solution two potential jumps can be observed. The first jump results from the acid group of the diester, the first neutralization step of the monoester, and the first neutralization step of free phosphoric acid. The second potential jump is caused by the second neutralization steps of the monoester and of the free phosphoric acid. The third step of neutralization of the free phosphoric acid cannot be covered by this method. Titration of acid esters can only be used for the determination of mono- and diesters of phosphoric acid when the amount of free phosphoric acid is separately ascertained. 

Phosphotriesterase from P. diminuta (PTE) was found to exhibit high hydrolytic activity towards various types of tetracoordinated phosphorus acid esters. Apart from the phosphonothionate 92, phosphoric acid triesters 94 (Equation 45), °" benzenephosphonic acid diester 95 (Equation 46) ° and methyl-phenylphosphinic acid ester 96 (Equation 47) were also stereoselectively hydrolysed under kinetic resolution conditions. Of course, in the case of the latter three kinds of substrates, half of the reacting ester was irreversibly lost due to the formation of achiral phosphorus acids. 

Tetrazolides of phosphorous acid esters or amides have been developed for the phos-phitilation of nucleosides. For instance, the tetrazolide of the diester of phosphorous acid (Af-tetrazolyldiethoxyphosphine) can be prepared either from diethylchlorophosphite and sodium tetrazolide (Method A) or from diethoxydiisopropylaminophosphine and two equivalents of tetrazole. The latter reaction (Method B) was undertaken to verify formation of a tetrazolide in the activation of phosphoramidites by tetrazole.[27]... 

Their hydrophobicity and their plasticity were appreciated and used for a long time in a wide range of activities. To our knowledge, the first wax to have been exploited is beeswax. Beeswax is produced by various species of bees in the world, and it has a melting point between 62°C and 64°C. It mainly contains homologous series of even-numbered fatty acids (C22 C34, C2 being the predominat compound), odd-numbered ra-alkanes (C2i C33, C27 being the major compound) and even-numbered palmitic esters from C40 to C52 (Tulloch and Hoffman, 1972 Kolattukudy, 1976). Hydroxy esters, diesters and hydroxy diesters also form part of beeswax to a lesser extent. 

The chemical diversity of carboxylic acid esters (R-CO-O-R ) originates in both moieties, i.e., the acyl group (R-CO-) and the alkoxy or aryloxy group (-OR7). Thus, the acyl group can be made up of aliphatic or aromatic carboxylic acids, carbamic acids, or carbonic acids, and the -OR7 moiety may be derived from an alcohol, an enol, or a phenol. When a thiol is involved, a thioester R-CO-S-R7 is formed. The model substrates to be discussed in Sect. 7.3 will, thus, be classified according to the chemical nature of the -OR7 (or -SR7) moiety, i.e., the alcohol, phenol, or thiol that is the first product to be released during the hydrolase-catalyzed reaction (see Chapt. 3). Diesters represent substrates of special interest and will be presented separately. 

The synthesis of succinic acid derivatives, /3-alkoxy esters, and a,j3-unsaturated esters from olefins by palladium catalyzed carbonylation reactions in alcohol have been reported (24, 25, 26, 27), but full experimental details of the syntheses are incomplete and in most cases the yields of yS-alkoxy ester and diester products are low. A similar reaction employing stoichiometric amounts of palladium (II) has also been reported (28). In order to explore the scope of this reaction for the syntheses of yS-alkoxy esters and succinic acid derivatives, representative cyclic and acyclic olefins were carbonylated under these same conditions (Table I). The reactions were carried out in methanol at room temperature using catalytic amounts of palladium (II) chloride and stoichiometric amounts of copper (II) chloride under 2 atm of carbon monoxide. The methoxypalladation reaction of 1-pentene affords a good conversion (55% ) of olefin to methyl 3-methoxyhexanoate, the product of Markov-nikov addition. In the carbonylation of other 1-olefins, f3-methoxy methyl esters were obtained in high yields however, substitution of a methyl group on the double bond reduced the yield of ester markedly. For example, the carbonylation of 2-methyl-l-butene afforded < 10% yield of methyl 3-methyl-3-methoxypentanoate. This suggests that unsubstituted 1-olefins may be preferentially carbonylated in the presence of substituted 1-olefins or internal olefins. The reactivities of the olefins fall in the order RCH =CHo ]> ci -RCH=CHR > trans-RCH =CHR >... 

Formation of quinuclidine-3-carboxylic acid derivatives (68) from these reactions was conclusive proof of saponification of the ethoxy-carbonyl group at position 2 of the diester (61). A similar reaction takes place with diethyl quinuclidine-2,3-dicarboxylate.100 This is in agreement with the known principle of easier saponification of a- than j8-amino acid esters. Some 3-(j8-acyloxyethyl)-2-diethylaminomethyl-quinuclidines (69, 70)123 on distillation at atmospheric pressure cyclize with loss of ester and formation of a new tricyclic system, quinuclidino[2,3-c]piperidine (72). The same reaction takes place by heating the corresponding amino alcohol (71) with phthalic anhydride in the presence of benzenesulfonic acid.123... 

Notes. (1) The mother-liquors from the washings and recrystallisations are saved for the recovery of 4-nitrophthalic acid. The combined mother-liquors are concentrated to small bulk and the organic acids extracted into ether. Upon esterification of the residue after evaporation of the ether by the Fischer-Speier method (Section 5.12.3, p. 695), the 3-nitro acid forms the acid ester and may be removed by shaking the product with sodium carbonate solution, while the 4-nitrophthalic acid yields the neutral diester. Hydrolysis of the neutral ester gives the pure 4-nitrophthalic acid, m.p. 165 °C. (2) The acid may also be recrystallised from glacial acetic acid. 

Kumler, W. D., Eiler, J. J. The Acid Strength of Mono and Diesters of Phosphoric Acid. The n-Alkyl Esters from Methyl to Butyl, the Esters of Biological Importance, and the Natural Guanine Phosphoric Acids. J. Am. Chem. Soc. 1943, 65, 2355-2361. 

Mecking showed an efficient way to produce a,G>diesters from fatty acid esters yielding excellent monomers for semicrystalline polyesters [63], Some part of the diesters was hydrogenated to diols and was transesterified with the diesters from the hydroesterification of methyl oleate into long-chain polyesters (Scheme 24). The properties of this thermomorphic polymer are related to those of polyethylene. 

Diacyloxy compounds are intermediates in the conversion of olefins and 1,2-dihalides to glycols (method 95). Although the diesters are seldom isolated, yields are good where their isolation has been attempted. The well-known reaction of an alkyl halide with a silver salt of an acid is used infrequently. It is sometimes valuable in making esters from acids which isomerize during direct esterification. Thus, the labile double bond of 3 niethyl-3-butenoic acid is unaffected by conversion to the methyl ester by this method. ... 

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