6307-98-8Relevant articles and documents
Synthesis and absolute configurations of the naturally occurring 3- and 4-methylmuconolactones: X-ray structures of (S)-1-phenylethylammonium salts and an 8-bromo-1-methyl-muconodilactone
Freer, Andrew A.,Kirby, Gordon W.,Rao, Ghanakota V.,Cain, Ronald B.
, p. 2111 - 2116 (1996)
(±)-3-Methylmuconolactone (±)-4 is resolved by fractional crystallisation of the (S)-(-)-1-phenylethylammonium salts. The X-ray crystal structures of both salts are determined. Salt A (Fig. 1) gives (S)-(-)-3-methylmuconolactone 4, which is identical to the lactone from fungi. The lactone is converted with bromine into the bromo dilactone 5 and thence with tributyltin hydride into the (-)-1-methylmuconodilactone 6. This dilactone with aqueous sodium hydroxide gives (S)-(+)-4-methylmuconolactone 3, which is identical to the lactone from bacteria, together with (S)-(-)-3-methylmuconolactone 4. The X-ray structure of the bromo dilactone 5 (Fig. 3) confirms the absolute configurations of both the fungal and bacterial muconolactones. (S)-(+)-4-Methylmuconolactone 3 gives the corresponding (-)-bromo dilactone 9, which is also reduced with tributyltin hydride to yield the (-)-1-methylmuconodilactone 6. The isomeric bromo dilactones (±)-5 and 9 are similarly converted into the dibromo dilactones (±)-8 and 11 via the corresponding 2-bromomuconolactones (±)-7 and 10, respectively. Disodium 3-methyl-cis,cis-muconate 17 is prepared non-enzymically by treatment of 3-methylmuconic anhydride 16 with 2 mol equiv. of aqueous sodium hydroxide. Unexpectedly, the salt 17 rapidly gives 3-methyl-2-cis,4-trans-muconate even in weakly alkaline solutions. Contrary to an earlier report, at pD 6.5 the salt 17 is converted at approximately equal rates into 3-methyl-2-cis,4-trans-muconic acid 18 and (±)-3-methylmuconolactone (±)-4.
Sustainable oxidative cleavage of catechols for the synthesis of muconic acid and muconolactones including lignin upgrading
Coupé, Florentin,Petitjean, Laurène,Anastas, Paul T.,Caijo, Frédéric,Escande, Vincent,Darcel, Christophe
supporting information, p. 6204 - 6211 (2020/10/18)
Muconic acid and muconolactones are attracting high interest as platform molecules for the synthesis of a variety of compounds, especially in the domain of materials. Although several technologies have been described for their synthesis, there is still a lack of performance, especially regarding green chemistry principles. In this study, we describe the development of an optimized catechol oxidative cleavage to muconic acid using performic acid in an intriguingly safe fashion. Common iron salts were used as catalysts to a level as low as 0.005 mol%, for a maximum turnover number of 13?200. Maximum muconic acid yield reached 84% after isolation by simple filtration. This procedure optimized on catechol was also efficient over a wide range of substituted catechols, providing access to muconolactones in a domino reaction. Noticeably, biobased catechols produced by a proven technology of lignin depolymerization were cleaved into muconolactones of high functional value. Applying this supplementary cleavage step to catechols obtained by lignin depolymerization was thus an ultimate way to maximize the economical value created from lignin. In contrast to other studies, lignin was not only depolymerized, but also depolymerization products were further transformed to take as much value from biomass as possible.
2-Methyl-(1Z,3E)-butadiene-1,3,4-tricarboxylic acid, " isoprenetricarboxylic acid"
Goren, Mayer B.,Sokoloski, Edward A.,Fales, Henry M.
, p. 7429 - 7431 (2007/10/03)
The synthesis of the title compound 7 from ethyl glyoxylate and dimethyl and diethyl β-methylglutaconate is described along with its physical properties that suggest its inability to assume a cis-dienoid structure due to steric hindrance between the methyl and carboxyl groups.
