Dicarboxylic acids reduction

There are two principal synthetic routes to dicarboxylate complexes. One of these uses an aqueous solution of the alkali metal dicarboxylate and the corresponding metal halide,93 while the other depends upon the dicarboxylic acid reduction of higher oxidation state metals. This reductive property of oxalic acid results in its ready dissolution of iron oxides and hence a cleaning utility in nuclear power plants.94 Mention must also be made of the successful ligand exchange synthesis of molybdenum dicarboxylates, Mo(dicarboxylate)2 H2 O, from the corresponding acetate complex. Unfortunately the polymeric, amorphous and insoluble nature of these complexes has restricted the study of these systems, which may well provide examples of multiple M—M bonding in dicarboxylate coordination chemistry.95... 

Regioselectivity of C—C double bond formation can also be achieved in the reductiv or oxidative elimination of two functional groups from adjacent carbon atoms. Well estab llshed methods in synthesis include the reductive cleavage of cyclic thionocarbonates derivec from glycols (E.J. Corey, 1968 C W. Hartmann, 1972), the reduction of epoxides with Zn/Nal or of dihalides with metals, organometallic compounds, or Nal/acetone (seep.lS6f), and the oxidative decarboxylation of 1,2-dicarboxylic acids (C.A. Grob, 1958 S. Masamune, 1966 R.A. Sheldon, 1972) or their r-butyl peresters (E.N. Cain, 1969). 

Isothiazole-4,5-dicarboxylic acid, 3-phenyl-dimethyl ester synthesis, S, 150 Isothiazole-5-glyoxylic acid ethyl ester reduction, 6, 156 Isothiazole-4-mercurioacetate reactions, 6, 164 Isothiazole-5-mercurioacetate reactions, 6, 164 Isothiazoles, 6, I3I-I75 acidity, 6, 141 alkylation, 6, 148 aromaticity, S, 32 6, 144-145 basicity, 6, I4I biological activity, 6, 175 boiling points, 6, I43-I44, 144 bond fixation, 6, 145 bond orders, 6, I32-I34 calculated, 6, 133 bromination, S, 58 6, 147 charge densities, 6, 132-134 cycloaddition reactions, 6, 152 desulfurization, S, 75 6, 152 deuteration, S, 70... 

IsoxazoIidine-3,3-dicarboxylic acid, 2-methoxy-dimethyl ester reaction with bases, 6, 47 Isoxazolidine-3,5-diones synthesis, 6, 112, 113 Isoxazoli dines conformation, 6, 10 3,5-disubstituted synthesis, 6, 109 oxidation, 6, 45-46 PE spectra, 6, 5 photolysis, 6, 46 pyrolysis, 6, 46 reactions, 6, 45-47 with acetone, 6, 47 with bases, 6, 47 reduction, 6, 45 ring fission, S, 80 spectroscopy, 6, 6 synthesis, 6, 3, 108-112 thermochemistry, 6, 10 Isoxazolidin-3-ol synthesis, 6, 111 Isoxazolidin-5-oI synthesis, 6, 111... 

Oxepin, 4-ethoxycarbonyl-2,3,6,7-tetrahydro-synthesis, 7, 578 Oxepin, 2-methyl-enthalpy of isomerization, 7, 555 Oxepin, 2,3,4,5-tetrahydro-reduction, 7, 563 synthesis, 7, 578 Oxepin, 2,3,4,7-tetrahydro-synthesis, 7, 578 Oxepin, 2,3,6,7-tetrahydro-oxidation, 7, 563 reduction, 7, 563 Oxepin-2,6-dicarboxylic acid stability, 7, 565 Oxepinium ions synthesis, 7, 559 Oxepins, 7, 547-592 antiaromaticity, 4, 535 applications, 7, 590-591 aromatization, 7, 566 bond lengths and angles, 7, 550, 551 cycloaddition reactions, 7, 27, 569 deoxygenation, 7, 570 dipole moment, 7, 553 disubstituted synthesis, 7, 584... 

Claisen ester condensation, 6, 279 Thiazolecarboxylic acid chlorides reactions, 6, 279-280 Thiazolecarboxylic acid hydrazides synthesis, 6, 280 Thiazolecarboxylic acids acidity, 6, 279 decarboxylation, 6, 279 reactions, S, 92 6, 274 Thiazole-2-carboxylic acids decarboxylation, S, 92 Thiazole-4-carboxylic acids stability, S, 92 Thiazole-5-carboxylic acids decarboxylation, S, 92 Thiazole-4,5-dicarboxylic acid, 2-amino-diethyl ester reduction, 6, 279 Thiazole-4,5-dicarboxylic acids diethyl ester saponification, 6, 279 Thiazolediones diazo coupling, 5, 59 Thiazoles, 6, 235-331 ab initio calculations, 6, 236 acidity, S, 49 acylation, 6, 256 alkylation, S, 58, 73 6, 253, 256 analytical uses, 6, 328 antifogging agents... 

Dicarboxylic acids have been prepared by the stepwise acylation and Wolff-Kishner reduction of thiophene or di-2-thienylmethane with ester chlorides of dicarboxylic acids. Another method consists of the AICI3 catalyzed acylation of w-phenylalkylthiophenes which occurs both in the free thiophenic position and in the para position of the ring (226). Hypochlorite oxidation and desulfurization then give diacides such as (227)... 

On oxidation with permanganate of potassium it yields sabinol-glycerine, CjoH,5(011)3, melting at 152° to 153°, and by further oxidation, tanacetogene-dicarboxylic acid, CpHj Og, melting at 140°. On reduction with sodium and amyl alcohol, sabinol yields thujyl alcohol, CjoHj OH. 

Scheme 12.19 illustrates some cases in which ozonolysis reactions have been used in the course of syntheses. Entries 1 to 4 are examples of use of ozonolysis to introduce carbonyl groups under reductive workup. Entries 5 and 6 involve oxidative workup and give dicarboxylic acid products. The reaction in Entry 7 is an example of direct generation of a methyl ester by methoxide trapping. 

Compared with the anodic oxidation of a 1,3-diene, the cathodic reduction of a 1,3-diene may be less interesting since the resulting simple transformation to monoolefin and alkane is more conveniently achieved by a chemical method than by the electrochemical method. So far, only few reactions which are synthetically interesting have been studied15. The typical pattern of the reaction is the formation of an anion radical from 1,3-diene followed by its reaction with two molecules of electrophile as exemplified by the formation of the dicarboxylic acid from butadiene (equation 22)16. 

In the case of 1,3-cyclohexadiene with Me2Zn, the dicarboxylation afforded the /rdicarboxylic acid 96 (Scheme 33). In contrast, when Ph2Zn was used instead of Me2Zn as a transmetallation agent, the phenylative carboxylation occurred in high regio- and stereoselectivity to give the l,4-m-substituted-2-cyclohexene 97, as a result of reductive elimination from the phenyl-7r-allylnickel intermediate, prior to the second carboxylation reaction (Scheme 33).47... 

A pulse polarographic system for detection of the dicarboxylic acid in the presence of nalidixic and hydroxynalidixic acids was devised by Koss and Warner.(45) The reduction potential in the system used was -.54V vs. SCE. 

But catalytic reduction of the same phenyl propionic acid gives cis cinnamic acid. Therefore by adding hydrogen under various conditions, one can obtain a desired isomer. The conversion of acetylene into olefinic compounds has been carried out not only for the sake of obtaining the adduct, but Michael studied the various addition reactions for the sake of obtaining a desired product cis or trans. For example, he found that the addition of bromine to acetylene-dicarboxylic acid leads predominantly to the formation of trans isomer. 

Its dicarboxylic acid, muconic acid, yields the /iy-unsaturated dihydromuconic acid on reduction ... 

In the above mentioned reaction, platinum oxide and palladium on barium sulfate showed no perceptible change in the rate of hydrogen uptake. On the other hand, platinum oxide was selective in the hydrogenation of cyclohexa-2,4-diene-l,2-dicarboxylic acid to 1,4,5,6-tetrahydrophthalic acid140. A similar result may be the favored reduction of a symmetrical disubstituted double bond over a more hindered trisubstituted bond. The retarding effect of additional substitution is demonstrated in the hydrogenation of a trisubstituted double bond in the presence of a tetrasubstituted double bond (equation 53)141. 

Partial reduction of the aromatic ring is especially easy in anthracene-9-carboxylic acid which was reduced to 9,10-dihydroanthracene-9-carboxylic acid with 2.5% sodium amalgam in aqueous sodium carbonate at 10° in 80% yield [987]. Aromatic carboxylic acids with hydroxyl groups in the ortho positions suffer ring cleavage during reductions with sodium in alcohols and are converted to dicarboxylic acids after fission of the intermediate j8-keto acids. 

Reductions of anhydrides of monocarboxylic acids to alcohols are very rare but can be accomplished by complex hydrides [55, 99]. More frequent are reductions of cyclic anhydrides of dicarboxylic acids, which give lactones. Such reductions were carried out by catalytic hydrogenation, by complex hydrides and by metals. 

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