- Structural features and antioxidant activities of Chinese quince (Chaenomeles sinensis) fruits lignin during auto-catalyzed ethanol organosolv pretreatment
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Chinese quince fruits (Chaenomeles sinensis) have an abundance of lignins with antioxidant activities. To facilitate the utilization of Chinese quince fruits, lignin was isolated from it by auto-catalyzed ethanol organosolv pretreatment. The effects of three processing conditions (temperature, time, and ethanol concentration) on yield, structural features and antioxidant activities of the auto-catalyzed ethanol organosolv lignin samples were assessed individually. Results showed the pretreatment temperature was the most significant factor; it affected the molecular weight, S/G ratio, number of β-O-4′ linkages, thermal stability, and antioxidant activities of lignin samples. According to the GPC analyses, the molecular weight of lignin samples had a negative correlation with pretreatment temperature. 2D-HSQC NMR and Py-GC/MS results revealed that the S/G ratios of lignin samples increased with temperature, while total phenolic hydroxyl content of lignin samples decreased. The structural characterization clearly indicated that the various pretreatment conditions affected the structures of organosolv lignin, which further resulted in differences in the antioxidant activities of the lignin samples. These results can be helpful for controlling and optimizing delignification during auto-catalyzed ethanol organosolv pretreatment, and they provide theoretical support for the potential applications of Chinese quince fruits lignin as a natural antioxidant in the food industry.
- Cheng, Xi-Chuang,Guo, Xin-Ran,Liu, Hua-Min,Liu, Yu-Lan,Qin, Zhao,Wang, Xue-De
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p. 4348 - 4358
(2020/09/22)
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- Candida antarctica lipase B-catalyzed regioselective deacylation of dihydroxybenzenes acylated at both phenolic hydroxy groups
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Candida antarctica lipase B proved to be highly active in the deacylation of substituted hydroquinones and resorcinols acylated at both phenolic hydroxy groups. The deacylation reactions were much faster than the corresponding direct acylations of these dihydroxybenzenes catalyzed by the same lipase. More importantly, they took place generally in a markedly regioselective manner: the acyloxy group remote from the substituent was preferentially cleaved. The main or exclusive products obtained were the regioisomers of those produced through the direct acylation of the dihydroxybenzenes. In the case of alkyl-substituted hydroquinone derivatives, the regioselectivity increased with an increase in the bulk of the substituent. In the case of 4-substituted diacylated resorcinols, the 3-O-monoacyl derivatives were obtained generally as the sole products. Quite interestingly, some secondary alcohols proved to act as better acyl acceptors than the corresponding primary alcohols in these enzymatic deacylations.
- Miyazawa, Toshifumi,Hamada, Manabu,Morimoto, Ryohei
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- PROCESS FOR STRAIGHTENING KERATIN FIBRES WITH A HEATING MEANS AND DENATURING AGENTS
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The invention relates to a process for straightening keratin fibres, comprising: (i) a step in which a straightening composition containing at least two denaturing agents is applied to the keratin fibres, (ii) a step in which the temperature of the keratin fibres is raised, using a heating means, to a temperature of between 110 and 250° C.
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- Secondary alcohols act as better nucleophiles than primary alcohols in the lipase-catalyzed regioselective deacylation of dihydroxybenzenes acylated at both phenolic hydroxyls
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Candida antarctica lipase B (CAL-B) was found to be highly regioselective as well as active in the deacylation of resorcinols and hydroquinones acylated at both phenolic hydroxyls. Contrary to expectation, secondary alcohols acted as better nucleophiles than primary alcohols in these enzymatic deacylations.
- Miyazawa, Toshifumi,Hamada, Manabu,Morimoto, Ryohei,Murashima, Takashi,Yamada, Takashi
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p. 8334 - 8337
(2008/03/14)
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- PROCESS FOR THE PREPARATION OF A COSMETIC ACTIVE
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A process for the preparation of a compound of formula (I) wherein R is a hydrogen or a C1-6 alkyl group which is straight chain, branched or cyclic, with or without an oxygen, nitrogen or sulphur heteroatom anywhere in the chain or ring by reacting a compound of formula (II) with a source of hydrogen selected from either hydrogen or water in the presence of a mixture of at least two catalysts selected from nickel, raney nickel, and palladium, at a pH below 7.0 in a solvent medium comprising an alcohol having a carbon chain length of up to 3.
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Page/Page column 13-14
(2008/06/13)
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- PROCESS FOR THE PREPARATION OF 4-ALKYL RESORCINOL ESTERS
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A process for the preparation of one or more esters of 4-alkyl resorcinol comprising the steps of: (i) reacting resorcinol or a pre-cursor thereof with an esterifying agent which comprises at least one of an organic acid, anhydride or chloride having a maximum carbon chain length of 18, at a temperature of 10 to 250 °C; and (ii) reducing the products from step (i) at a pH of 6.5 to 7.5 in the presence of a catalyst in an alcoholic medium.
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- Synthesis and study of antibacterial activity of some Schiff bases derived from sulfonamide, 4-amino antipyrene and raceacetophenone
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Schiff bases derived from sulfonamide, 4-amino antipyrene and raceacetophenone were screened for antibacterial activity against various clinical isolates (obtained from Urine, Blood, Tracheal secretion and Pus). Extracts of these compounds were evaluated on 5 pathogenic strains [E. coli, Pseudomonas aeruginosa, Proteus vulgaris, Klebsiella pneumoniae and Staphylococcus aureus]. The antibacterial activity was evaluated using the Agar Ditch method. The Schiff bases produced were (1) 4-[2-aza-2- (2-chlorophenyl) vinyl] benzene sulfonamide [AD1] (2) 4-[2-aza-2- (2-hydroxyphenyl) vinyl] benzene sulfonamide [AD2] (3) [1-aza-4-phenylbuta-1, 3-dienyl] benzene sulfonamide [AD3] (4) 4-[1-aza-2- (2chlorophenyl) vinyl]-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one [AS1] (5) 4-[1-aza-2-(2-hydroxyphenyl) vinyl]-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one [AS2] (6) 4-[1-aza-4-phenylbuta-1, 3-dienyl] 2,3-dimethyl-1-phenyl-3-pyrazolin-5-one [AS3] (7) 4-[2-aza-1-methyl-2- (2-nitro phenyl) vinyl]-6-ethylbenzene-1, 3-diol [ADS1] (8) 4-[2-aza-2(5-ehtyl-2, 4-dihydroxyphenyl) prop-1-enyl] benzene sulfonamide [ADS2]. The anti bacterial activity of these Schiff bases, were evaluated in one polar and one non polar (i.e., DMF and 1,4 dioxan) solvents. It is found that among AD and AS compounds AD compounds are better than AS and AD3 is the best while 1,4 dioxan solvent proved to be more effective than DMF. It appears that the sulfonamide moiety present with cinnamaldehyde side chain could be used as a lead molecule in drug designing (i.e. in inhibiting the above pathogenic bacteria).
- Nair,Shah,Baluja,Chanda
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p. 463 - 479
(2007/10/03)
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- Tyrosinase activity inhibitor
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Disclosed is a chemically stable tyrosinase activity inhibitor having high tyrosinase activity inhibition effect and low toxicity. The tyrosinase activity inhibitor has a structure of the formula: STR1 wherein R1, R3 and R4 are a hydrogen atom or an alkyl or alkenyl group having 1 to 9 carbon atoms, and R2 is an alkyl or alkenyl group having 2 to 9 carbon atoms.
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- DEOXYGENATION OF ALDEHYDES AND KETONES WITH SODIUM CYANOBOROHYDRIDE
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Treatment of hydroxy-substituted aromatic aldehydes and ketones with sodium cyanoborohydride yields the corresponding methylene compounds under conditions which favor intermediate carbonium ion formation.
- Elliger, Carl A.
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p. 1315 - 1324
(2007/10/02)
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