- p-Cymene as Solvent for Olefin Metathesis: Matching Efficiency and Sustainability
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The underexploited biorenewable p-cymene is employed as a solvent for the metathesis of various substrates. p-Cymene is a nontoxic compound that can be obtained in large amounts as a side product of the cellulose and citrus industry. For the cross-metathesis of estragole with methyl acrylate, this solvent prevents the consecutive double-bond isomerization of the product and affords the best yield of all solvents tested. Undesired consecutive isomerization is a major challenge for many substrates in olefin metathesis, including pharmaceutical precursors, and the use of p-cymene as a solvent may be a way to prevent it. This solvent results in a better metathesis performance than toluene for the three substrates tested in this work, matching its performance for two other substrates.
- Granato, Artur V.,Santos, Alexandra G.,dos Santos, Eduardo N.
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p. 1832 - 1837
(2017/04/27)
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- Allyl/propenyl phenol synthases from the creosote bush and engineering production of specialty/commodity chemicals, eugenol/isoeugenol, in Escherichia coli
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The creosote bush (Larrea tridentata) harbors members of the monolignol acyltransferase, allylphenol synthase, and propenylphenol synthase gene families, whose products together are able to catalyze distinct regiospecific conversions of various monolignols into their corresponding allyl- and propenyl-phenols, respectively. In this study, co-expression of a monolignol acyltransferase with either substrate versatile allylphenol or propenylphenol synthases in Escherichia coli established that various monolignol substrates were efficiently converted into their corresponding allyl/propenyl phenols, as well as providing proof of concept for efficacious conversion in a bacterial platform. This capability thus potentially provides an alternate source to these important plant phytochemicals, whether for flavor/fragrance and fine chemicals, or ultimately as commodities, e.g.; for renewable energy or other intermediate chemical purposes. Previous reports had indicated that specific and highly conserved amino acid residues 84 (Phe or Val) and 87 (Ile or Tyr) of two highly homologous allyl/propenyl phenol synthases (circa 96% identity) from a Clarkia species mainly dictate their distinct regiospecific catalyzed conversions to afford either allyl- or propenyl-phenols, respectively. However, several other allyl/propenyl phenol synthase homologs isolated by us have established that the two corresponding amino acid 84 and 87 residues are not, in fact, conserved.
- Kim, Sung-Jin,Vassao, Daniel G.,Moinuddin, Syed G.A.,Bedgar, Diana L.,Davin, Laurence B.,Lewis, Norman G.
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- GLYCOSIDE COMPOUND
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Compounds of formula (I″) wherein: R11, R12, R13, R14 and R15 are hydrogen, hydroxyl, C1-6 alkyl, C1-6 alkoxy, C1-6 alkyl-carbonyloxy, or a G-O— group, and at least one of R11, R12, R13, R14 and R15 is a G-O— group, wherein G is a saccharide residue,X1 is a single bond, or a methylene group, an ethylene group, a trimethylene group, a vinylene group or —CH═CH—CH2—,X2 is —CO—O— or —O—CO—,p and q are integer ofs 0 to 7, and p+q=0 to 8,Y1 is methylene, ethylene or an alkenylene group having a carbon number of 2 to 15 and 1 to 3 double bonds, andR16 and R17 are hydrogen, methyl or ethyl, or R16 and R17 form a C3-6 cycloalkyl group, are useful as GLP-1 secretion promoting agents.
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Paragraph 0399; 0400
(2013/11/06)
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- Preparation of monolignol γ-acetate, γ-p-hydroxycinnamate, and γ-p-hydroxybenzoate conjugates: Selective deacylation of phenolic acetates with hydrazine acetate
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We report here a reliable and facile synthesis of a range of monolignol γ-p-hydroxycinnamate (including p-coumarate, ferulate, and caffeate), γ-acetate, and γ-p-hydroxybenzoate conjugates, many not previously reported, that are either putative intermediat
- Zhu, Yimin,Regner, Matthew,Lu, Fachuang,Kim, Hoon,Mohammadi, Allison,Pearson, Timothy J.,Ralph, John
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p. 21964 - 21971
(2013/11/06)
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- DFRC Method for Lignin Analysis. 1. New Method for β-Aryl Ether Cleavage: Lignin Model Studies
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A new method for selective and efficient cleavage of arylglycerol-β-aryl (β-O-4) ether linkages in lignins is described and applied to several lignin β-ether models. The term "DFRC" was coined for derivatization followed by reductive cleavage. Derivatization, accompanied by cell wall solubilization, is accomplished with acetyl bromide (AcBr); reductive cleavage of resulting β-bromo ethers utilizes zinc in acetic acid. Degradation monomers, 4-acetoxycinnamyl acetates, from β-ether cleavage by the DFRC method were identified by NMR, GC-MS, and comparison of GC retention times with authentic compounds. Under the conditions used in this study, the β-ether linkage of all models was cleaved in very high (>92%) yield. The DFRC method produces simpler mixtures of monomers with higher yields than alternative hydrolytic methods. Because of its relative simplicity, mild conditions, and exceptional selectivity, this method should become a powerful analytical method for lignin characterization.
- Lu, Fachuang,Ralph, John
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p. 4655 - 4660
(2007/10/03)
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- 1'-Hydroxyeugenol- and coniferyl alcohol derivatives as effective inhibitors of 5-lipoxygenase and Cu(2+)-mediated low density lipoprotein oxidation. Evidence for a dual mechanism.
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1'-Hydroxyeugenol- and epoxy-Z-coniferyl alcohol esters from Coreopsis species as well as synthetic derivatives of these natural compounds were examined as lipoxygenase inhibitors and as LDL (low density lipoprotein)-stabilizing agents. Most of the compounds displayed inhibitory activity on the formation of leukotrienes (LTB4 and LTC4) in a cellular (RBL-1 cells) assay as well as in a cell-free 5-lipoxygenase assay at concentrations of 4-24 mumol/l. No effect of selected compounds was observed on mammalian lipoxygenases with other specificity (12- and 15-lipoxygenase). The more lipophilic derivatives also effectively reduced Cu(2+)-mediated oxidation of LDL. The findings are discussed on the base of structure-activity relationships.
- Deigner,Wolf,Ohlenmacher,Reichling
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p. 956 - 961
(2007/10/02)
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- SELECTIVE DEACETYLATION OF AROMATIC ACETATES BY AMINOLYSIS
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Pyrrolidine was shown to deacetylate aromatic acetyl groups considerably faster than aliphatic groups.
- Mansson, Per
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p. 1845 - 1846
(2007/10/02)
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