Muconate, preparation

Muconic acid has been obtained in a variety of ways. The procedures that seem most important from a preparative point of view are by treatment of ethyl o ,5-dibromoadipate with alcoholic potassium hydroxide, by condensation of glyoxal (as the sodium bisulfite addition product) with malonic acid, by heating ethyl l-acetoxy-l,4-dihydromuconate (obtained by condensing ethyl oxalate and ethyl crotonate, acetylating, and reducing),and by oxidation of phenol with peracetic acid. ... 

Ozonization of lignin forms derivatives of muconic acid that have the unique chemical structure of conjugated double bonds with two carboxyl groups. These derivatives have great potential for chemical modification. The ozonized lignin of white birch was soluble in epoxy resin at 120°C, and the free carboxyl groups were found to react with epoxide. This paper discusses developmental work on the preparation of pre-reacted ozonized lignin/epoxy resins the dynamic mechanical properties of cured resins and preliminary results of the application of these resins as wood adhesives. 

In the presence of trace amounts of water, the tetrameric p,2-oxo complex (182) in 1,2-dimethoxyethane is transformed into a p, -oxo tetrameric complex (183 equation 254), characterized by an X-ray structure.574 In contrast, (182) 572,575 is inactive towards the oxidation of phenols. The reaction of N,N,N, AT -tetramethyl-l,3-propanediamine (TMP) with CuCl, C02 and dioxygen results in the quantitative formation of the /z-carbonato complex (184 equation 255).s76 This compound acts as an initiator for the oxidative coupling of phenols by 02. 6 Such jz-carbonato complexes, also prepared from the reaction of Cu(BPI)CO with 02 [BPI = 1,3 bis(2-(4-methyl-pyridyl)imino)isoindoline],577 are presumably involved as reactive intermediates in the oxidative carbonylation of methanol to dimethyl carbonate (see below).578 Upon reaction with methanol, the tetrameric complex (182 L = Py X = Cl) produces the bis(/z-methoxo) complex (185 equation 256), which has been characterized by an X-ray structure,579 and is reactive for the oxidatiye cleavage of pyrocatechol to muconic acid derivatives.580,581... 

Yoshida et al. [197] developed thermostable materials based on ozonized lignin. Hence, the authors ozonized lignin to prepare muconic acid or its hemi-ester, as shown in Scheme 46. 

Reagent 1 also converts anhydrides such as 2, prepared as indicated, to muconic acid derivatives (3 and 4) (equation II).3... 

The uptake and biotransformation of benzene from soil and from the atmosphere have been studied in a number of plants, and it was shown that in leaves of spinach (Spinacia oleracea), the label in 14C-benzene was found in muconic, fumaric, succinic, malic, and oxalic acids as well as in specific amino acids, and that an enzyme preparation in the presence of NADH or NADPH produced phenol (Ugrekhelidze et al. 1997). 

Degradation of catechol and 3,4-dihydroxybenzoate — The key observation was that the ring-cleavage product of catechol or 3,4-dihydroxybenzoate was P-ketoadipate that is formed by a series of lactonizations and rearrangements. The various steps were elucidated using pure samples of the proposed intermediates and enzyme preparations to study induction patterns. Mutants were then used to elucidate the regulation of the pathways cis,cis-muconate is the inducer for the catechol pathway, and P-ketoadipate for the 3,4-dihydroxybenzoate pathway (Ornston 1966). 

Protocatechuate 3,4-dioxygenase. Crystalline preparations of the enzyme were obtained as described previously (2). The enzyme catalyzes the intradiol cleavage of protocatechuic acid with the insertion of two atoms of molecular oxygen to form /8-carboxy cis,cis-muconic acid (Reaction 3). 

Oxepan and other oxygen- or nitrogen-containing saturated heterocycles can be prepared in high yield by the dehydrative coupling of aamino-alcohols, using diethyl azodicarboxylate and triphenylphosphine. The synthetically useful oxepin-2,7-diones (muconic acid anhydrides) can be conveniently prepared by the oxidation of ortho-henzoquinones with w-chloroperoxybenzoic acid. °... 

The syntheses of mono- and dicarboxylic acids via ionic reaction steps starting from butadiene and carbon dioxide are well studied reactions. For instance, Cg-, C13- and C-]7-monocarboxylic acids as well as Ciq-dicarboxylic acids can be prepared in the presence of sodium [72,73]. Also metal phenolates catalyze the synthesis of acyclic dicarboxylic acids. When sodium phenolate is dissolved in dimethylformamide and CO2 and butadiene are added and reacted 3 hrs at 50 C, muconic acid is formed in 81 % yield. Hydrogenation of muconic acid leads to adipic acid [741. In a similar reaction, Thiele s acid, that is tricyclo-[5.2.1.02 6]deca-3.8-diene-4.9-dicarboxylic acid, is formed by two moles of cyclopentadiene and two moles of carbon dioxide [79 (Equation 13). 

Copper(II) reagents for the conversion of catechols and o-benzoquinones to muconic acid monoesters can also be prepared by adding a nucleophile ROH (R = Me, Et, n-Pr, etc. ) to the products of oxidation of CuCl in pyridine [40],... 

Compatibilized blends of hydroxylated polyoxymethylene (polyacetal) with carboxylic acid-functionalized PP have been prepared (Chen et al. 1991). The formadtHi of ester linkages between the polymers was proposed. For example, blends comprising hydroxylated polyoxymethylene and muconic acid-grafted PP were made into film by calendering at 200 °C to provide compositions with markedly improved mechanical properties compared to similar blends containing unfunctionahzed PP or unfunctionalized polyoxymethylene. 

Reaction of the verrucarinic acid derivative (247) with verrucarol (82), mediated by DCC and 4-N,N-dimethylaminopyridine (DMAP), yielded the monoester (250) by exclusive acylation at C-15. A similar esterification procedure attached the muconic acid (249) to C-4. Following desilylation the seco acid (251) was cyclized (52%) and deacetylated to yield verrucarin A (37). When alternative conditions for the esterification of acid (249) were employed, partial isomerization of the , Z-isomer (251) to an E,E-isomer was observed. However, lactonization of this mixture produced only the natural E,Z-macrocyclic (37) as the E,E-isomer failed to cyclize. Such reactivity differences have been observed with other trichothecanoid macrocycles (22, 148), although, as shall be seen, E,E-macrocycles can be prepared if so desired 115, 121). 

Horcajada et al. prepared smooth PCP films by the deposition of [Fe30Cl(muc)3] (where muc = muconate dicarboxylate) nanocrystals by a dip-coating method. Uniform nanocrystals were obtained by applying the coordination modulation method. Following a similar strategy, Guo et al. prepared luminescent thin films with controllable thickness by spin-coating of nanoscale [Ln(btc)(H20)] (where Ln = Dy +, Eu +, or Tb +). ... 

We show an example of the case of poly(l,4- diethyl c/s,cis-muconate). We prepare a single crystal of 1,4-diethyl cw,cw-muconate from the solution and irradiate with the X-ray beam for the structure analysis of the monomer and the polymer. Since the structural changes occur rapidly during the polymerization reaction, that is, on a time scale of several tens of minutes under the X-ray irradiation, fast acquisition of the X-ray reflections is necessary for accurate structural analysis. A CCD camera makes it possible to collect about 6(XX) reflections in 13 minutes [130]. 

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