Dicarboxylic acid monoesters esters

Cyclic mew-configurated 1,2-dicarboxylic acid dimethyl esters are excellent substrates for pig liver esterase90. Cyclopropanedicarboxylales have been studied not only for synthetic reasons, but also so that an active-site and/or substrate model of pig liver may be developed13 5. The results obtained, compounds 11-17, are a good demonstration of the scope and limitation of PLE in asymmetric synthesis. Enantiomeric excesses of the monoesters can be determined by conversion into the amides with (S)-l-phenylethylamine and analysis either by GC or H-NMR spectroscopy, whereas the absolute configuration rests on chemical correlation. 

Brown-Walker reaction — Important generalization and extension of the Kolbe reaction (1891) (- Kolbe synthesis) leading to the synthesis of a variety of long-chain dicarboxylic acids and esters using monoesters of dicar-boxylic precursors. Among the most used application belongs the production of sebacic acid diethylester from hydrogen ethyladipate... 

Potassium permanganate acetic acid Dicarboxylic acid monoesters from hydroxycarboxylic acid esters... 

Dicarboxylic acid chloride esters from dicarboxylic acid anhydrides via dicarboxylic acid monoesters with cis-frcms-rearrangement... 

Potassiumitert-butanol-molecular sieve Dicarboxylic acid monoesters via mixed dicarboxylic acid esters Preferential transesterification... 

Monoesters of some dicarboxylic adds are subject to metal ion hydrolysis. The effect of micellization on cupric ion-promoted hydrolysis of dicarboxylic acid hemi-esters has been the subject of an investigation by Ong and Kostenbauder [82]. 

The first synthesis of 4-pyrone derivatives with two CF3 groups was reported in 1988 by Lee and co-workers [22]. Acetone dicarboxylic acid monomethyl ester 47 reacted with isobutylene in sulfuric acid to form 48. Subsequent reaction with MgCL and trifluoroacetic anhydride led to pyrone 49. This compound was converted to the monoester 50, which gave pyrone 51. The latter was reacted with ammonia in methanol to form 4-hydroxypyridine 52 [22] (Scheme 15). 

Aspartic acid y -esters—Dicarboxylic acid monoesters from dicarboxylic acid anhydrides. A soln. of 0.054 mole maleic anhydride in ahs. methanol refluxed 30 min., excess methanol distilled in vacuo, the monomethyl maleate thus obtained cooled in ice-water, pyridine followed by 0.05 mole isobutylamine added. 

Dicarboxylic acid chloride esters from dicarboxylic acid monoesters... 

The formation of relatively ill-defined catalysts for epoxide/C02 copolymerization catalysts, arising from the treatment of ZnO with acid anhydrides or monoesters of dicarboxylic acids, has been described in a patent disclosure.968 Employing the perfluoroalkyl ester acid (342) renders the catalyst soluble in supercritical C02.969 At 110°C and 2,000 psi this catalyst mixture performs similarly to the zinc bisphenolates, producing a 96 4 ratio of polycarbonate polyether linkages, with a turnover of 440 g polymer/g [Zn] and a broad polydispersity (Mw/Mn>4). Related aluminum complexes have also been studied and (343) was found to be particularly active. However, selectivity is poor, with a ratio of 1 3.6 polycarbonate polyether.970... 

Systematic studies150,153 with CLX50, (7), decyl esters of pyridine monocarboxylic acids (8)-(10), and dipentyl esters of pyridine dicarboxylic acids (11)—(15) showed that extraction of Cu11 is strongly dependent on the activity of water and the total concentration of ionic and molecular species in the aqueous phase. For the monoesters, copper distribution is dependent on... 

Esters for lubricant applications are divided into five groups monocarboxylic acid esters (monoesters), dicarboxylic acid esters (diesters), glycerol esters, polyol esters, and complex esters. 

Phthalate esters undergo a step-wise alkaline hydrolysis to monoesters and then to dicarboxylic acids. As a result of the relatively slow rates of this reaction at pH 6-9 and the low water solubility of di-n-octylphthalate, chemical hydrolysis of the compound is not an environmentally important transformation process (EPA 1992a). Hydrolytic half-lives at 25 C and pH 7 and 9 have been estimated to be 107 and 7 years, respectively (Howard et al. 1991). 

Kolbe electrolysis is generally useful for the formation of hydrocarbons from monocarboxylic acids and for the preparation of many difunctional compounds as well. A specific illustration is the synthesis of esters of long-chain dicarboxylic adds from monoesters of appropriate dicarboxylic acids (see p. 33). A number of these syntheses are discussed by Fichter.4 In the present preparation, a two-compartment cell is employed to avoid, or at least greatly reduce, undesired reduction of the nitro group at the cathode. It seems likely that the procedure could be adapted to the preparation of other difunctional compounds containing groups that are easily reduced. 

MixedPhosphonate Esters. Unsaturated, mixed phosphonate esters have been prepared from monoesters of 1,4-cyclohexanedimethanol and unsaturated dicarboxylic acids. For example, maleic anhydride reacts with this diol to form the maleate, which is treated with benzenephosphonic acid to yidd an unsaturated product. These esters have been used as flame-retardant additives for thermoplastic and thermosetting resins (97). 

This reaction provides a useful way of introducing a double bond next to a carbonyl group. Here it is in a synthesis by Barry Trost of the Queen Bee Substance (the compound fed by the workers to those bee larvae destined to become queens). The compound is also a pheromone of the termite and is used to trap these destructive pests. Trost started with the monoester of a dicarboxylic acid, which he converted to a methyl ketone by reacting the acyl chloride with a cuprate. The ketone was then protected as a dioxolane derivative to prevent it enolizing, and the sulfur was introduced by reacting the enolate of the ester with the sulfur electrophile MeSSMe. 

The usual range of carboxylic acid derivatives can be prepared and interconverted. Both carboxylic acid and ester functions are capable of reduction by lithium aluminum hydride to alcohols, or by controlled potential reduction to aldehydes. Attempts to form the anhydride from imidazole-4,5-dicarboxylic acid by heating with acetic anhydride failed. Instead, compound (199) is formed. This product forms the monoester (200) when heated with methanol and the hydrazide (201) when treated similarly with hydrazine (Scheme 107) (75S162). The corresponding l-methyl-4,5-dicarboxylic acid loses the 4-carboxyl group when heated with acetic anhydride, but in boiling aniline it is transformed into the 1-methyl-4-carboxanilide (79H(12)186). 

A closely related reaction is equilibration of a dicarboxylic acid and its diester to produce monoesters The reaction of a carboxylic acid with ethyl acetate, in the presence of NaHS04 Si02, was shown to give the corresponding ethyl ester. Iodine catalyzes the transesterification of p-keto esters. 

Resolution of alcohols requires a more ingenious approach in order to acquire suitable diastereomeric salts for resolution by recrystallization. The racemic alcohol, ROH, to be resolved is first converted to its phthaiate monoester 36 (phthalic acid is benzene- 1,2-dicarboxylic acid). The strategy here is to leave one carboxylic acid group free, and available to form diastereoisomeric salts with an amine such as 34 or 35. Once the appropriate ammonium salt of 36 has been resolved, the amine is removed by acidification to give one enantiomer of 36, and this ester is then hydrolysed with alkali to give one enantiomer of ROH. The more soluble diastereomeric ammonium salt can then, in principle, be processed similarly to yield the other enantiomer. 

Klein and Neff358 prepared mono- and di-ketones as well as oxo esters in excellent yield by treating alkylzinc iodides with carbonyl chlorides, dicarbonyl dichlorides, or monoester monochlorides of dicarboxylic acids. The alkylzinc iodides were obtained directly from the alkyl iodides and a zinc-copper alloy in toluene-ethyl acetate, as in the following example. 

The main oxidation products of the methyl esters of aliphatic acids containing n C atoms are methyl esters of dicarboxylic acids C4—C 3, aliphatic acids Ci— Cn-i, and keto- and hydroxy compounds [301—307]. Oxidation of acetates (140—160° C) yield acids, carbon dioxide, hydroxy, and keto compounds (see Table 17). Hydroperoxide is the primary product of oxidation. Oxidation of dimethyl esters of dicarboxylic acids gives monoesters with a lower number of C atoms in the acidic group (see Table 17). Carbon dioxide is formed in parallel with acids and monoesters [308]. All monoesters C 1 Cn 2 etc. are also formed in parallel. This suggests several mechanisms of C—C bond scission in the oxidation, an a-mechanism with only one C—C bond broken to form Cm and C — products, a /3-mechanism with two C—C bonds broken in the /3-position to form Cm, C —m— and C02, etc. The a, /3, and 7-mechanisms of C—C bond scission may be regarded as a result of peroxy radical isomerization to form labile dihydroperoxides, e.g. 

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