Experimental study on light volatile products from thermal decomposition of lignin monomer model compounds: effect of temperature, residence time and methoxyl group

Effects of temperature, residence time and methoxyl on the decomposition of phenol, guaiacol and syringol, were investigated. Thermal decomposition pathways of the three model compounds were discussed based on ring reduction/CO elimination reactions.

Methoxylation of quinoidal bithiophene as a single regioisomer building block for narrow-bandgap conjugated polymers and high-performance organic field-effect transistors

Methoxyl group was introduced to obtain isomer-free methoxylation quinoidal bithiophene building block. Four polymers displayed narrow bandgap (<1.20 eV) and hole mobility of up to 2.70 cm2 V−1 s−1.

Quercetagetin and Patuletin: Antiproliferative, Necrotic and Apoptotic Activity in Tumor Cell Lines

Quercetagetin and patuletin were extracted by the same method from two different Tagetes species that have multiple uses in folk medicine in Mexico and around the globe, one of which is as an anticancer agent. Their biological activity (IC50 and necrotic, apoptotic and selective activities of these flavonols) was evaluated and compared to that of quercetin, examining specifically the effects of C6 substitution among quercetin, quercetagetin and patuletin. We find that the presence of a methoxyl group in C6 enhances their potency.

Inhibition of Lipoxygenase and Peroxidase Reaction by Some Flavonols and Flavones: The Structure-Activity Relationship

Some flavonoids were investigated for their effects on lipoxygenase and peroxidase. The strongest inhibitor of lipoxygenase was kaempferol with one hydroxyl group situated at the 4’ position in the B ring, with activity of 21.2±2.03 calculated per μmole of compound. The weakest inhibition was observed for diosmetin with a hydroxyl group at the 3′ position and a methoxyl group at 4′ in the B ring, with activity of 1.17±0.77 per μmole. Peroxidase was most strongly inhibited by quercetin (22.7±0.05) with two hydroxyl groups in the B ring at 3′ and 4′. The weakest inhibitor of peroxidase was genkwanin (0±0.16) with one hydroxyl group at position 4′ in the B ring and methoxyl at position 7 in the A ring. The correlation coefficient between reduction of Fe3+ by flavonoids and inhibition of lipoxygenase by these compounds was 0.72 and the reduction of Fe3+ and inhibition of peroxidase was 0.24. The results show that inhibition of peroxidase is weakly associated with reducing properties of phenols and inhibition of lipoxygenase may be associated with antioxidant properties of flavonoids.

Syndioselective coordination polymerization of unmasked polar methoxystyrenes using a pyridenylmethylene fluorenyl yttrium precursor

A new family of syndiotactic polystyrene derivatives containing a methoxyl group was established successfully by employing a yttrium catalyst.

Characterization of polysaccharides isolated from stem of Angelica dahurica

Such pectin (5.77±0.02)%, fiber (24±0.01)%, lignine (10.790.03)% have been founded in the medicinal herb called ‘Angelica’. The average molecule mass of pholysugar was determined by the methodology of chromatography of chromatography of gel-filtration of the (15500-400000). It has founded first time that the glucose thermal galactose has connected as 1,4 connection in connection with the monomer assortment of neutral pholysugar founded in monosaccharide. The rhamnose-terminal, xylose-terminal are connected by 1,3 connection in the circulation of macromolecule of polysaccharide. Pectin of substance derivative compound to extract. In polysaccharide has to establish etherify carboxyl group (7.47)% and methoxyl group (5.14)% and etherification degree (51.4)%. DOI: http://dx.doi.org/10.5564/mjas.v11i2.236 Mongolian Journal of Agricultural Sciences Vol.11(2) 2013 pp.142-145

Synthesis, and Properties of 1-[2-methyl-5-(1,3-difluorophenyl)-3-thienyl]-2-[2-methyl-5-(4-methoxylphenyl)-3-thienyl]perfluorocyclopentene

A new unsymmetrical photochromic diarylethene 1-[2-methyl-5-(1,3-difluorophenyl)-3-thienyl]-2-[2-methyl-5-(4-methoxylphenyl)-3-thienyl] perfluorocyclopentene has been synthesized,which a methoxyl group was substituted at the para-positions of the terminal phenyl ring. The photochromism of this compound was investigated, the results showed that this compound exhibited reversible photochromism, inducing cyclization and cycloreversion reactions upon alternating irradiation with UV and visible light both in solution and in a PMMA film. When irradiated 297 nm UV light, in hexane solution the maximum absorption was observed at 289 nm and 588 nm in opening-ring form and in close-ring form, respectively.

Synthesis of 4-Methoxysalicylaldehyde via Selective Monomethylation of 2,4-Dihydroxybenzaldehyde

4-Methoxysalicylaldehyde, a naturally occurring product, has a range of industrial applications in the preparation of organic compounds, drugs and therapeutic agents. 4-Methoxysalicylaldehyde can be synthesised via selective monomethylation of 2,4-dihydroxybenzaldehyde in toluene in the presence of NaHCO3 in higher yield using cheaper reagents with little production of dimethylation product compared to previous methods. The location of the methoxyl group was confirmed by conversion to 3-acetyl-7-methoxycoumarin by condensation with ethyl acetoacetate.

Photochromism of a New Unsymmetrical Diarylethene Bearing both Thiazole and a Methoxyl Group

A new unsymmetrical isomeric diarylethene bearing an electron-donating methoxyl group atortho-positions of the terminal phenyl ring was synthesized, namely 1-(2,4-dimethyl-5-thiazolyl) -2-[2-methyl-5-(2-methoxyphenyl)-3-thienyl]perfluorocyclopentene (1o). The compound displayed excellent photochromism both in solution and in PMMA film. The isomeric compound also functioned as a fluorescence switch by photoirradiation in solution. In addition, cyclic voltammetry tests showed that the electron-donating methoxyl group at the terminal benzene ring had a significant effect on the electrochemical properties of the isomeric diarylethene.