• Journal of the Korean Chemical Society
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• v.55 no.4
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• pp.633-637
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• 2011

Iron (III) phosphate was employed as an efficient catalyst for the chemo selective acetylation of alcohols and phenols under solvent free condition at room temperature and with high yields. Iron (III) phosphate is also a potential green catalyst due to solid intrinsically, reusable and with high catalytic activity.

• Korean Chemical Engineering Research
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• v.51 no.6
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• pp.716-726
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• 2013

Enzymatic acylations catalyzed by hydrolytic enzymes, along with enzymatic hydrolysis, are established reactions in the synthesis of fine chemicals such as chiral intermediates and polymerizations in the industry. Those reactions have been carried out mostly in organic media due to the thermodynamic limitations. Recently, there have been reports on enzymatic acylations in aqueous media. They have dealt with the elucidation of reaction mechanisms of hydrolases and acyl transferases based on their X-ray structures, homology comparison of the two kinds of enzymes, substrate engineering of acyl donors and computational design of acyl transferases for enzymatic acylations in aqueous media. Enzymatic acylations play an important role in the combinatorial synthesis of natural products such as polyketides and nonribosomal peptides. In this review, the historic developments of enzymatic acylations and industrial examples are described briefly. In addition, recent developments of enzymatic acylations in the modification of natural products and their prospects will be discussed.

• Journal of the Korean Chemical Society
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• v.35 no.5
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• pp.580-585
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• 1991

Quinolone derivatives have been used as antibacterial agents. In this work, the competitive C-and O-acylation reaction of 3,4-dichloroacetophenone, as a model study for the synthesis of quinolone intermediate, is studied. The effects of various bases, solvents and the leaving groups of acylating agents on the ratio of C-versus O-acylation of 3,4-dichloroacetophenone are elucidated by means of employing ethylchloroformate, ethylphenylcarbonate and diethylcarbonate as acylating agents. In aprotic solvents, C-acylation reactions occur more predominantly as the size of metal ions composing bases becomes smaller. Regarding the effects of leaving groups, it is shown that C-acylation product is increased as the ability of leaving groups of acylating agents decreases. The ratio of C/O-acylation is also observed to be increased as the polarity of solvents decreases.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2005.05a
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• pp.202-206
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• 2005

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2005.05a
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• pp.228-232
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• 2005

• Journal of the Korean Applied Science and Technology
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• v.12 no.2
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• pp.41-50
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• 1995

2염기성 산의 모노메틸에스테르류와 에틸렌디아민을 반응시켜 얻은 아미도아민 유도체류를 고급지방산 염화물로 아실화하여 N-아실 아미도에틸 N-아미도카르복시산 유도체 9종을 합성하였다. 카르복시기와 디아미드기 그리고 소수성의 긴 알칼사슬을 갖는 모든 반응생성물들은 얇은 막 크로마토그래피와 컬럼크로마토그래피로 분리 ${\cdot}$ 정제하였다. 합성 수율은 $74{\sim}87%$였으며 그들의 구조를 FT-IR, $^1H-NMR$, 그리고 원소 분석으로 확인하였다.

• The Korean Journal of Pesticide Science
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• v.9 no.3
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• pp.185-190
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• 2005

Solid phase synthesis of 16, which is a derivative of the first systemic fungicide, carboxin 1 was described. Reaction of 1,3-oxathiolane derivative with solid resin of 4-hydroxy-3-nitrobenzophenone 6 gave 9 in 82% yield. Oxidation of sulfur in the solid 1,3-oxathiolane 9 by MCPBA followed by a ring expansion reaction under the acid catalyst afforded the corresponding dihydro-1,4-oxathiin derivative 12. Treatment of the solid 1,3-oxathiolane 9 with p-methoxyaniline resulted in 1,3-oxathiolane 14, 1,3-oxathiolane sulfoxide 15, dihydro-1,4-oxathiin 16, and acetoacetanilide derivative 17 in 41%, 35%, 14%, 10% yields, respectively.

• Applied Chemistry for Engineering
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• v.8 no.3
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• pp.365-373
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• 1997

Chitosan oligomer having aldehyde group at reducing end was prepared by oxidative-deamination reaction of chitosan by using sodium nitrite, and the resulting aldehyde group was redeced to 2,5-anhydro-D-mannitol group. The obtained chitosan oligomer showed an average degree of polymerization(DP) 2 by GPC analysis. It was highly soluble in lipophilic solvents. N,N-diacyl, O-acyl chitosan oligomer was obtained trom the reaction between chitosan oligomer and acyl chloride under 4-dimethoxyaminopyridine catalyst. From DSC measurement, N,N-dilauroyl, O-lauroyl chitosan oligomer showed mesophase region, which was confirmed by polarizing microscope as thermotropic liquid crystalline state. X-ray diffraction pattern revealed that N,N-dilauroyl, O-lauroyl chitosan oligomer was highly crystalline, whereas chitosan oligomer was not.

• Korean Journal of Food Science and Technology
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• v.12 no.4
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• pp.263-271
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• 1980

Detoxified and deallergenized castor bean protein isolate was prepared from defatted castor bean pomace for use in animal feedstuffs and human foods. Succinylation and acetylation of the ${\varepsilon}-amino$ groups of the protein improved markedly the water solubility of the protein at $pH\;7{\sim}8$. The results of the amino acid analysis of the protein isolate revealed that the sulfur-containing amino acids and L-lysine were limiting amino acids and that succinylation and acetylation caused some little loss of the amino acid content. The L-methionine enriched plastein was synthesized from the protein isolate or the acylated protein isolates and DL-methionine ethyl ester by one step process with papain. By this method the extent of incorporation of L-methionine was about 50%. Pepsin hydrolyzed both unmodified and modified protein isolates at the same rate (about 92%). Tryptic hydrolysis, however, was less for the succinylated protein isolates (about 42%) and less for the acetylated protein isolates (about 26%). The protein efficiency ratio of L-methionine enriched protein isolate (about 2.5 weight %) was 90% that of reference casein. The protein efficiency ratio values of succinylated (88%) and acetylated (84%) protein isolate were 55 and 69% of reference casein, respectively.

• Journal of Life Science
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• v.12 no.1
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• pp.32-42
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• 2002

It was researched to react horse serum-BChE with hefanoylthiocholine chosen among choline esters. According as number of carbon of acyl group in choline esters was increased, reactivity was decreased but strength of ES complex was increased (Km=0,140mM). The pH-V/K profile for BChE-catalyzed hydrolysis of hexanoylthiocholine yields a p $K_{a}$ =4.974$\pm$0.028. This value is equal to recent literature that shows systematic shift from dependence of activity on the basic form fo a residue that huts a p $K_{a}$ =6.2~6.4 to catalysis by a residue or residues that has a p $K_{a}$ =4.7~5.0. The resulting kinetic solvent isotope effect of hexanoylthiocholine is $^{D/V}$K=1.18. The magnitude of the isotope effect suggests that proton transfer is not an element of transition-state stabilization.n.