Muconic acid derivatives

Conversion of Cyclic to Acyclic Structures. Upon oxidation, the aromatic rings of lignin may be converted direcdy to acycHc stmctures, eg, muconic acid derivatives, or indirectly by oxidative splitting of o-quinoid rings. Further oxidation creates carboxyUc acid fragments attached to the lignin network. 

Neither the mechanism by which benzene damages bone marrow nor its role in the leukemia process are well understood. It is generally beheved that the toxic factor(s) is a metaboHte of benzene (107). Benzene is oxidized in the fiver to phenol [108-95-2] as the primary metabolite with hydroquinone [123-31-9] catechol [120-80-9] muconic acid [505-70-4] and 1,2,4-trihydroxybenzene [533-73-3] as significant secondary metabolites (108). Although the identity of the actual toxic metabolite or combination of metabolites responsible for the hematological abnormalities is not known, evidence suggests that benzene oxide, hydroquinone, benzoquinone, or muconic acid derivatives are possibly the ultimate carcinogenic species (96,103,107—112). 

Bisphenol A, a compound highly used in the production of epoxy resins and polycarbonate plastics, forms monochloro-, dichloro, trichloro-, and tetrachloro derivatives when chlorinated [127], Its reaction with ozone produces as major transformation products, catechol, orthoquinone, muconic acid derivatives of bisphenol A, benzoquinone, and 2-(4-hydroxyphenyl)-propan-2-ol [128],... 

Table 1 Stereospecific solid-state photoreaction of (Z,Z)-muconic acid derivatives depending on the structure of alkyl substituents ...

The enzyme catalyzes the intradiol cleavage of catechol with the insertion of 2 atoms of molecular oxygen to form e/s.c/s-muconic acid. The enzyme also catalyzes the oxidation of various catechol derivatives, including 4-methylcatechol, 4-chloro-catechol, 4-formylcatechol (protocatechualdehyde), 4,5-dichlorocatechol, 3,5-di-chlorocatechol, 3-methylcatechol, 3-methoxycatechol, and 3-hydroxycatechol (pyro-gallol). All of these substrates give products having an absorption maximum at around 260 nm characteristic of t7s-c/s-muconic acid derivatives. However, when 3-methylcatechol is used as a substrate, the product formed shows an absorption maximum at 390 nm besides that at 260 nm. These two absorption maxima are found to be attributable to two different products, 2-hydroxy-6-oxo-2,4-heptadienoic acid (7), and 5-carboxy-2-methyl-2,4-pentadienoicacid(2-methylmuconic acid), (2) [Eq. (19)]96. ... 

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... 

A biomimetic catechol cleavage reaction was carried out on dihydro-caffeic acid derivative 1922 using the iron(III)-catalyzed peracetic acid cleavage process of Pandell.25 This produced the cyclized muconic acid derivative 20 which could be transformed into pyrone 21 by treatment with hydrochloric acid. Bromination followed by azide displacement gave key intermediate 22 which could either be reduced directly to (i)-stizolobic acid 16 or ammonolyzed and then reduced to give ( )-3-(6-carboxy-2-oxo-4-pyridyl)alanine 17 (Scheme 4). 

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

Lahav, M. and Schmidt, G.M.J. (1967) Topochemistry. Part XXIII. The solid-state photochemistry at 25° of some muconic acid derivatives. J. Chem. Soc. B, 312-317. 

Matsumoto, A., Katayama, K., Odani, T., Oka, K., Tashiro, K., Saragai, S. and Nakamoto, S. (2000) Feature of y-radiation polymerization of muconic acid derivative in the crystalline state. Macromolecules, 33, 7786-7792. 

Selective esterification of the primary alcohol of natural verrucarol (113) with 112 cleanly provided 114 in 95% yield. Although 114 is apparently resistant to a second esterification with 112, the more reactive muconic acid derivative 108... 

Linstead and coworkers" investigated alkali-catalyzed y3-elimination of the diacetate and dimethanesulfonate of dimethyl (+ )-3,4-dihydroxy-hexanedioate [(-I-)-/3,j8 -dihydroxyadipate] resulting in a trans,trans-muconic acid derivative. An unusually facile, double (irons )-jS-elimina-tion was found" in the reaction of dimethyl galactarate (15) with methanesulfonyl chloride in pyridine dimethyl irons,frans-2,5-di(methyl-sulfonyloxy)mucoate (17) was obtained by esterification to give 16... 

Resorcinol (22) was converted to 2-hydroxybenzoquinone (105 Lin et al., 1984). Phenols related to lignin were partly converted to quinones, but also to ring-opened products such as muconic acid derivatives, and to polymeric materials (Masschelein,... 

As is the case for biobased polyolefins, the production of the polymer from the biobased monomer is identical to production of petro-based PET, and the resulting properties are identical (except for the ratio of carbon isotopes, as discussed above). Several routes to terephthalic acid are currently under consideration. They include routes through isobutanol, para-xylene, and muconic acid, derived from various plant sources. 

Two kinds of mechanisms for Fe dioxygenase action have thus far been proposed, viz. (i) insertion via a dioxetane intermediate (23) [79], and (ii) insertion via a monooxygenated muconic acid derivative... 

A biogenesis of cyclopentenones from pulvinic acid precursors along the lines of Scheme 25 must also be considered 202). In this regard the rearrangement of O-methylpulvinone to 4-methoxy-2,5-di-phenylcyclopent-4-ene-l,3-dione mediated by 4% methanolic potassium hydroxide 426) is noteworthy. Decarboxylation of an intermediate muconic acid derivative has also been invoked 481). 

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