N-Methylimidazole significantly improves lipase-catalysed acylation of ribavirin

Liu, Bo‐Kai; Wu, Qi; Xu, Jia‐Zhuang; Lin, Xianfu

doi:10.1039/b611454g

Cited by 34 publications

(26 citation statements)

References 16 publications

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“…More importantly, NMI is a derivative of imidazole with a slightly more basic N-methyl group as indicated by the pK a 's of the conjugate acids of 7.0 and 7.4 (Zhang et al 2012). This means that NMI can act as a solvent, a base and an excellent acylation catalyst in DMSO/ NMI solvent system (Lu and Ralph 2003;Liu et al 2007;Zhang et al 2012). Because the esterification of xylan with anhydride is acid-or base-catalyzed reaction, NMI shows promise in accelerating the esterification reaction.…”

Section: Resultsmentioning

confidence: 99%

Per-O-acylation of xylan at room temperature in dimethylsulfoxide/N-methylimidazole

Zhang

Liu

et al. 2016

Cellulose

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The per-O-acylation of xylan-type hemicellulose was firstly carried out in dimethylsulfoxide/ N-methylimidazole (DMSO/NMI) at room temperature without additional catalyst. The optimum conditions for esterification of xylan was investigated in terms of the molar ratio of reagents to anhydroxylose units (AXU) in xylan and the kinds of esterification reagents to obtain a high degree of substitution (DS, 1.98) and weight percent gain (WPG, 86.88 %) of xylan esters. In this solvent system, NMI acted as a solvent, a base and an excellent catalyst, therefore, the per-O-acylation of xylan (DS of 1.98) was readily accomplished in DMSO/NMI system at room temperature. Structure elucidation of xylan esters was characterized by FT-IR and NMR ( 1 H-NMR, 13 C-NMR and HSQC). FT-IR and NMR analyses provided the direct evidence of per-O-acylation of xylan under the given conditions. Furthermore, HSQC revealed the higher reactivity of hydroxyls at C-2 position than those at C-3 position of xylan. The solubility of xylan in DMSO, DMF and CHCl 3 improved after esterification. TGA/DTG indicated that the thermal stability of xylan increased after the esterification with anhydrides, while decreased with acyl chlorides, probably due to degradation and hydrolysis of the acylated xylan at the presence of by-product hydrochloric acid.

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Section: Resultsmentioning

confidence: 99%

Per-O-acylation of xylan at room temperature in dimethylsulfoxide/N-methylimidazole

Zhang

Liu

et al. 2016

Cellulose

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“…[1] N-Methylimidazole is known to be an effective catalyst for the aza-Michael reaction of N-heterocycles, [8] the enzymatic acylation of ribavirin, [9] esterification and amide formation reactions, [10] aldol reactions of silyl enol ether with aldehydes, [11] the Baylis-Hillman reaction, [12] condensation [13] between carboxylic esters and acid chlorides or acids, and other [14] reactions. Small amounts (1-5 mol-%) of N-methylimidazole, as a basic impurity significantly affected H/D exchange in the synthesis of perdeuterated ILs.…”

Section: Introductionmentioning

confidence: 99%

Kinetic Study of Michael Addition Catalyzed by N‐Methylimidazole in Ionic Liquids: Residual N‐Methylimidazole in Ionic Liquids as a Strong Base

Mečiarová¹,

Cigáň²,

Tomá³

et al. 2008

Eur J Org Chem

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Michael addition of malonodinitrile to chalcone was studied in classical organic solvent as well as in some common ionic liquids (ILs). Kinetic studies proved that the reaction proceeded faster in the studied ILs than in molecular solvents. N‐methylimidazole was found to be a better basic catalyst in some ILs than in conventional solvents. Residual N‐methylimidazole in imidazolium‐based ILs can act as a basic catalyst. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

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“…Walker and Bruce (2004) have recently described a combined chemical and enzymatic method for the production of oxycodone. However, this process involves the use of ionic liquids that are relatively expensive for industrial scale use (Liu et al 2007;Wasserscheid 2007) In this regard; the ability of N. muscorum to convert codeine to oxycodone represents an uncommon pattern of codeine metabolism in microorganisms that may be of industrial importance. Fig.…”

Section: Resultsmentioning

confidence: 99%

Bioconversion of codeine to semi-synthetic opiate derivatives by the cyanobacterium Nostoc muscorum

Niknam

Faramarzi

Abdi

et al. 2009

World J Microbiol Biotechnol

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Very limited studies have been done to investigate the algal biotransformation of codeine to its opioid derivatives. On the other hand, microalgae have been recently introduced as potential tools for green synthesis of various organic compounds. In the present work, the capability of biotransformation of codeine by a locally isolate strain of cyanobacterium, Nostoc muscorum, was evaluated. Incubation of the whole cells of Nostoc muscorum with codeine (I) under continuous light photoregime of 60 lmol photons/m 2 s at 25°C for 5 days gave rise to four transformation products. The bioproducts were separated by gas chromatography and identified as 6-acetylcodeine (II), oxycodone (III), norcodeine (IV), morphine (V) and based on their mass spectra. Observed modifications included O-demethylation, N-demethylation, C6-acetylation, C14-hydroxilation, D 7 -reduction, and C6-oxidation. The ability of N. muscorum to convert codeine to oxycodone (III) represents an uncommon pattern of codeine metabolism in microorganisms that may be of industrial importance.

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N-Methylimidazole significantly improves lipase-catalysed acylation of ribavirin

Abstract: N-methylimidazole, a molecular solvent, but also, in cationic form, a component of 1-alkyl-3-methylimidazolium ([C(n)MIM]+) ionic liquids, showed promise as an additive in accelerating remarkably transesterification catalyzed by lipase acrylic resin from Candida antarctica (CAL-B).

Cited by 34 publications

References 16 publications

Per-O-acylation of xylan at room temperature in dimethylsulfoxide/N-methylimidazole

Per-O-acylation of xylan at room temperature in dimethylsulfoxide/N-methylimidazole

Kinetic Study of Michael Addition Catalyzed by N‐Methylimidazole in Ionic Liquids: Residual N‐Methylimidazole in Ionic Liquids as a Strong Base

Bioconversion of codeine to semi-synthetic opiate derivatives by the cyanobacterium Nostoc muscorum

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