18181-71-0Relevant articles and documents
Cleavage of CC and Co bonds in β-O-4 linkage of lignin model compound by cyclopentadienone group 8 and 9 metal complexes
Kishino, Masamichi,Kusumoto, Shuhei,Nozaki, Kyoko
supporting information, p. 477 - 480 (2020/05/19)
Degradation of 1-(3,4-dimethoxyphenyl)-2-(2-methoxyphe-noxy)propane-1,3-diol (1), a model compound for lignin β-O-4 linkage was examined with iron, ruthenium, rhodium and iridium complexes bearing cyclopentadienone ligand. Cyclopentadienone iron complex gave only a small amount of degraded product with reduced molecular weight. Cyclopentadienone ruthenium complex, so called Shvo's catalyst, afforded 3,4-dimethoxybenzaldehyde (a3) in 14.3% yield after CαCβ bond cleavage. On the other hand, cyclopentadienone group-9 metal complexes catalyzed CβO bond cleavage to afford guaiacol (b1) as a main product in up to 74.9% yield.
Method for depolymerizing lignin into aromatic compound through photocatalysis (by machine translation)
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Paragraph 0047-0052, (2019/07/29)
The invention relates to a method, for depolymerizing lignin into an aromatic compound by photocatalysis. Belong to application chemistry technical field. The method uses lignin as a reaction substrate, and under the excitation of a light source, under the catalysis of a light source, the C-C bond is selectively cracked under the assistance of a base and a hydrogen donor, and the molar ratio of the reaction substrate, photocatalyst, base, and hydrogen donor is 100: (0.5~10) 1~20: (1~20), and the reaction temperature is room temperature, and the reaction substrate is a reaction substrate. The reaction time was 6~24 hours. The method has the advantages, such as simple reaction steps, mild reaction conditions, high bond breaking selectivity 100%, high yield, atom efficiency, environmental protection and the like, has the functions, is high in selectivity, and efficiently degrades the lignin, and is beneficial to large-scale industrial production and application of lignin degradation and the like. (by machine translation)
Revisiting Hydroxyalkylation of Phenols with Cyclic Carbonates
Kao, Shih-Chieh,Lin, Yi-Ching,Ryu, Ilhyong,Wu, Yen-Ku
supporting information, p. 3639 - 3644 (2019/07/10)
Described is a tetrabutylammonium fluoride-mediated hydroxyalkylation reaction of phenols with cyclic carbonates. This operationally simple method enables the synthesis of a variety of aryl β-hydroxyethyl ethers in good to excellent yields with a very small amount of catalyst loading (0.1–1 mol%). Of particular note is the efficient conversion of aromatic diols and phloroglucinol to the corresponding bis- and tris-hydroxyethylated products. To further showcase the versatility of this protocol, guaifenesin was prepared with a single step by the condensation of guaiacol and glycerol carbonate. We also developed a flow ethoxylation process permitting the continuous synthesis of multiflorol. (Figure presented.).
