Enyzmatic amidation of the primary amines β-alanine ethyl ester and 3-aminopropionitrile with methyl laurate by means of immobilized
lipase (Candida antarctica lipase, CAL) resulted in the formation in good yield of N-lauroyl-β-alanine ethyl ester and 3-(N-lauroylamino)-propionitrile, respectively. When 3-amino-propionitrile was used as substrate, diisopropyl ether was a suitable
solvent. Changing the reaction temperature (12–80°C) did not affect the yields, and room temperature was a suitable temperature
for this reaction. In the investigation of reaction conditions, the use of equimolar amounts (5 mmol) of substrate and ester,
along with 0.5 g of CAL, in diisopropyl ether gave the best yield (99.3%) after 24 h of incubation at 24°C. The enzyme activity
in the amidation reaction did not decrease even after six uses. With β-alanine ethyl ester hydrochloride as substrate, diisopropyl
ether was unsuited as a solvent owing to the low solubility of the substrate in this solvent.
In this reaction, the best yield (82.0%) was attained by using dioxane as solvent. CAL achieved higher extents of amide synthesis
with long-chain than with short-chain ester substrates. The enzyme accepted only nonbulky primary amines as substrates. 相似文献
Amidation of bovine β-lactoglobulin (β-Lg) imparted antimicrobial properties to this protein. Amidated β-Lg was strongly bactericidal against resting cells of Pseudomonas fluorescens, Pseudomonas fragi and Bacillus subtilis, but had a much weaker effect against Escherichia coli, Enterococcus faecalis, Salmonella typhimurium and Listeria monocytogenes. Neither native nor amidated β-Lg was effective against the yeast Saccharomyces cerevisiae and the mould Penicillium candidum. Mass spectrometric analysis demonstrated that amidation of β-Lg converted aspartyl and glutamyl residues to asparaginyl and glutaminyl residues, respectively, and that the amidation reaction did not occur to the same extent on every β-Lg molecule. The charge change was also confirmed by SDS–PAGE, ion exchange chromatography and the change in isoionic point of β-Lg. Reverse-phase chromatography showed that amidation also led to alterations in hydrophobicity of the β-Lg molecule. The antibacterial properties of the amidated β-Lg appear to be dependent on the net positive charge and charge distribution on the molecule. 相似文献
Copper(I) bromide‐catalyzed amidation of 2‐arylpyridine derivatives and 1‐methylindoles with a variety of amides was achieved by employing tert‐butyl peroxide (TBP) as oxidant. Aryl halides could be tolerated under the reaction conditions. Neither a special ligand nor a base was required for this amidation process. 相似文献
A novel and highly efficient copper‐catalyzed tandem synthesis of triazoloquinazolinones is explored. The synthetic strategy involves a sequential one‐pot click reaction followed by aerobic intramolecular C H amidation. Two distinct and important transformations were carried out in one‐pot by employing a single cost‐effective copper catalyst. The milder, rapid and ligand‐free reaction conditions as well as a broader substrate scope are the salient features of this novel protocol.
A low-temperature synthesis of laurel oil alkanolamides directly from laurel oil and ethanolamine was carried out in essentially
quantitative yields. The ethanolamine/laurel oil molar ratio used was 10∶1. Even though amine served as a catalyst in the
reaction, we used sodium methoxide at a ratio of 0.2–2% as a second catalyst. The reaction was complete in 1–9 h at room temperature.
The identity of the amide was confirmed by IR and 13C NMR spectroscopy. 相似文献
