824-46-4Relevant articles and documents
Control of reaction pathways in the photochemical reaction of a quinone with tetramethylethylene by metal binding
Yamamoto, Hiroaki,Ohkubo, Kei,Akimoto, Seiji,Fukuzumi, Shunichi,Tsuda, Akihiko
, p. 7004 - 7017 (2014)
The present study reports a novel supramolecular photochemical reaction that focuses on the direct electronic interactions between a host reaction substrate and guest metal salts. The reaction pathways in the photochemical reactions of quinone derivatives bearing a methoxy group and a long oligoether sidearm QEn (n = 0 and 3) with tetramethylethylene (TME) are changed upon noncovalent complexations of the host reactant with alkali and alkaline earth metal ions and a transition metal salt. The photochemical reaction of QEn with TME provides a mixture of [2 + 2] cycloadducts 1aE n and 1bEn, hydroquinone H2QEn, and monoallyl ether adducts of hydroquinones 2aEn and 2bEn. The photochemical reaction proceeds by the photoinduced electron transfer mechanism, where photoirradiation brings about formation of a radical ion pair [QEn-, TME+] as the primary intermediate. We found that the yields and selectivity of these photoproducts are changed upon electronic interactions of QEn- with the metal salts. The photochemical reaction in the absence of metal salts provides H 2QEn as its major product, whereas QE3, having the long sidearm, dominantly produces 2aE3 at the expense of 1aE 3, 1bE3, and H2QE3 when it forms a size-favorable host-guest complex with divalent Ca2+. In contrast, QEn selectively provides oxetanes 1aEn and 1bEn in the presence of Pd(OAc)2, which can form complexes with the quinone through metal-olefin and coordination interactions in the ground and photoexcited states of the quinone. This journal is the Partner Organisations 2014.
AROMATIC GLYCOSIDES FROM BERCHEMIA RACEMOSA
Inoshiri, Shogo,Sasaki, Manami,Kohda, Hiroshi,Otsuka, Hideaki,Yamasaki, Kazuo
, p. 2811 - 2814 (1987)
Key Word Index-Berchemia racemosa; Rhamnaceae; lignan; aromatic glycoside; nudiposide; secoisolariciresinol glucoside; isotachioside; tachioside; syringic acid glucosyl ester; 13C NMR. Two new aromatic glucosides have been isolated from the stems of Berchemia racemosa together with the known glycosides, nudiposide, (-)-secoisolariciresinol-O-β-D-glucopyranoside and methoxyhydroquinone-1-O-β-D-glucopyranoside (isotachioside).The structures of the new glucosides were found to be β-D-glucopyranosyl syringate, and methoxyhydroquinone-4-O-β-D-glucopyranoside on the basis of chemical and spectral evidences.
Study of the Oxidative Cleavage Proposed in the Biogenesis of Transtaganolides/Basiliolides: Pyran-2-one Aromaticity-Mediated Regioselective Control and Biogenetic Implications
álvarez, José María,Jorge, Zacarías D.,Massanet, Guillermo M.
supporting information, (2020/03/05)
The synthetic feasibility of the oxidative cleavage: epoxidation of 7-O-geranylscopoletin followed by electrocyclic ring-opening, proposed in the biogenesis of transtaganolides/basiliolides is studied. Unlike the proposed pericyclic reactions, this pathway has not yet been addressed. Three synthetic strategies have been tested consisting of: i) Baeyer–Villiger oxidation of p-quinoids, ii) hydrolysis of quinone monoketals, or iii) direct fragmentation by using oxygen donors. Oxidation of the benzene ring of hydroxylated coumarins has been achieved using peroxyacids, but cleavage took place between undesired positions. The aromaticity conservation of the pyran-2-one cycle during oxidation is the controlling factor of these observed regioselectivities. The use of a 4,5-dihydroxy-2-methoxycinnamate model, in which the pyran-2-one ring does not exert influence on oxidation, has allowed the design of a synthetic sequence toward an analogue of the natural pyran-2-one isolated from Thapsia transtagana, key in the biogenesis. Mechanistic proposals for the obtained results as well as their biogenetic implications are raised.
FLAME-RETARDANT VANILLIN-DERIVED MONOMERS
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Paragraph 0035, (2018/11/26)
A flame-retardant vanillin-derived monomer, a process for forming a flame-retardant polymer, and an article of manufacture comprising a material that contains flame-retardant vanillin-derived monomer are disclosed. The flame-retardant vanillin-derived monomer can be synthesized from vanillin obtained from a bio-based source, and can have at least one phosphoryl or phosphonyl moiety with phenyl, allyl, epoxide, or propylene carbonate substituents. The process for forming the flame-retardant polymer can include reacting a vanillin derivative and a flame-retardant phosphorus-based molecule to form the flame-retardant vanillin-derived monomer, and then polymerizing the flame-retardant vanillin-derived monomer. The material in the article of manufacture can be flame-retardant, and contain the flame-retardant vanillin-derived monomer. Examples of materials that can be in the article of manufacture can include resins, plastics, adhesives, polymers, etc.
