Immobilization of lipase on biocompatible co-polymer of polyvinyl alcohol and chitosan for synthesis of laurate compounds in supercritical carbon dioxide using response surface methodology
摘要:
Biocompatible co-polymer matrix has great importance for enzyme immobilization and subsequent bio-catalytic applications to synthesize important organic moieties. Citronellyl laurate is a fatty-acid-ester having pleasant fruity aroma and widely used as/in emulsifier, lubricant in textile, paint or ink-additives, surfactants, perfumery and food-flavouring ingredient. In present study, Burkholderia cepacia lipase (BCL) was immobilized on biodegradable co-polymer of chitosan (CHI) and polyvinyl alcohol (PVA). The synthesized bio-catalyst {PVA:CHI:BCL (6:4:2.5)} was characterized by SEM, TGA, lipase assay and protein-content analysis. This biocatalyst was applied to synthesize citronellyl laurate in supercritical carbon-dioxide (SC-CO2) using response surface methodology with five-factor-three-level Box-Behnken-design to optimize reaction parameters (citronellol: 8.5 mmol; vinyl laurate: 19.87 mmol; biocatalyst: 175.6 mg; temperature: 46.02 degrees C; pressure: 8.81 MPa) which provided 94 +/- 1.52% yield. The protocol is extended to synthesize various important 12 laurate compounds with excellent yield (90-98%) and noteworthy recyclability (upto studied 5 recycles). Interestingly, immobilized PVA/CHI/lipase biocatalyst showed 4-fold higher bio-catalytic activity than free lipase in SC-CO2. Moreover, the biocatalyst activity assessment study showed remarkable activity-stability of immobilized biocatalyst in SC-CO2 media as compared to free enzyme. Thus, present protocol demonstrated potential biocatalytic applications for synthesis of important laurate compounds with excellent recyclability in SC-CO2 as greener biocatalyst and reaction medium. (C) 2015 Elsevier Ltd. All rights reserved.
EFFICIENT ESTERIFICATION OF ALIPHATIC CARBOXYLIC ACIDS CATALYZED BY COPPER METHANESULFONATE
作者:Jie Ma、Heng Jiang、Hong Gong
DOI:10.1080/00304940509355406
日期:2005.2
solid super acid^,'^ etc. The esterification of carboxylicacids with equimolar amounts of alcohols using eco-friendly catalysts, such as new solid reagents that are less toxic and facilitate recovery and recycling, is a most desirable goal. We now report copper methanesulfonate (CMS)” exhibits efficient catalytic activity and reusability in some esterifications of aliphatic carboxylicacids with alcohols
Identification and synthesis of new sex-specific components of olive fruit fly (Bactrocera oleae) female rectal gland, through original Negishi reactions on supported catalysts
GC/EI-MS, at different moments of the insect life span, highlighted the growing trend of their secretion. While for the synthesis of saturated esters, conventional transesterification methods could be adopted, for the synthesis of unsaturated components, a Negishicross-coupling between organozinc halides and (Z)-1-bromo-1-alkenes was developed. To the extent of our knowledge, this reaction represents
The invention provides a method of sustained delivery of a tertiary amine-containing parent drug comprising administering to a patient an effective amount of a prodrug compound of the invention wherein upon administration to the patient, release of the parent drug from the prodrug is sustained release. Prodrug compounds suitable for use in the methods of the invention are labile quaternary ammonium salts of tertiary amine-containing parent drugs (or tertiary imine-containing parent drugs) that are derivatized through aldehyde-linked prodrug moieties that reduce the solubility of the prodrug compound at a reference pH as compared to the parent drug. The physical, chemical and solubility properties of these derivatives can be further modulated by the choice of counterion X
−
. In one embodiment, the present invention provides a prodrug compound of Formula I:
where R
1
-R
5
are defined in the written description of the invention. The prodrug compounds of the invention can be used to treat any condition for which the tertiary amine-containing parent drug or tertiary imine-containing parent drug is useful as a treatment.
The present invention relates to prodrugs of parent drug compounds containing heteroaromatic NH groups.
本发明涉及包含杂环氮原子基团的母药化合物的前药。
A method for improving the release of a cast concrete item from the mould by applying to the mould a mould release composition
申请人:CASTROL A/S
公开号:EP0328158A1
公开(公告)日:1989-08-16
The release of a moulded concrete body from the mould can be improved by applying to the mould an effective amount of a concrete release composition comprising one or more oily esters of aliphatic carboxylic acids with mono- or dihydric alcohols, with a melting point of at the most 35°C, the total number of carbon atoms in the esters being 8-46, in an amount of 26-100% by weight, calculated on the total composition, optionally in admixture with other additives such as mineral oils, vegetable oils, glycols, glycol ethers, alkanols, emulsifiers and/or water.