• 청정기술
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• 제22권4호
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• pp.269-273
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• 2016

The benzylic bromination of methoxyimino-o-tolyl-acetic acid methyl ester (1) into (2-bromomethyl-phenyl)-methoxyimino-acetic acid methyl ester (2) using N-bromosuccinimide in the presence of 2,2'-azobisisobutyronitrile in various reaction solvents were investigated. The efficiency of the reaction was found to be sensitive to the kind of reaction solvents. We found the benzylic bromination of 1 to 2 can be performed in 1,2-dichlorobenzene as reaction solvent superior to the classic Wohl-Ziegler procedure in both reaction time and isolated yield (8 h vs 12 h, 92 vs 79%). This system provides clean, rapid, and high-yielding reactions with replacement of conventional solvents, such as tetrachloromethane, by less-toxic 1,2-dichlorobenzene.

• 약학회지
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• 제33권2호
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• pp.80-86
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• 1989

2,6-Dimethyl-4-(3'-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid 3-methyl 5-(2'-phenylsulfinyl) ethyl ester (10) or 2,6-Dimethyl-4-(2' or 3'-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid 3-alkyl 5-(2-methylsulfonyl) ethyl ester (14a, b, c) were hydrolyzed by treatment with NaOH in aqueous EtOH solution to give 2,6-Dimethyl-4-(3'-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid monomethyl ester (4b), 2,6-Dimethyl-4-(2'-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid monomethyl ester (4c) and 2,6-Dimethyl-4-(2'-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid monoisopropyl ester (4d) in 80 -90% yield. By the same procedure, 2,6-Dimethyl-4-(3'-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid 3,5-bis (2'-methylsulfonyl) ethyl ester (15) gave 2,6-Dimethyl-4-(3'-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid (4e) in 96% yield.

• 한국응용과학기술학회지
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• 제19권2호
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• pp.137-144
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• 2002

Methyl glycoside oleic acid polyester was successfully prepared from methyl glycosides and methyl oleate by emulsion interesterification in the presence of methyl fructoside oleic acid polyester as an emulsifier. Emulsion interesterification process was optimized to obtain 98% yield of methyl glycoside polyester within $3{\sim}5hr$ at temperatures as relatively low as $90{\sim}150^{\circ}C$ and $20{\sim}200mmHg$ pressure with a five-fold molar ratio of oleic acid methyl ester to methyl glycoside in the presence of 2(w/w)% potassium carbonate and 2O(v/v)% methyl fructoside polyester based on oleic acid methyl ester.

• Bulletin of the Korean Chemical Society
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• 제4권2호
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• pp.72-76
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• 1983

Cephaloglycin was synthesized directly from D-${\alpha}$ -phenylglycine methyl ester and 7-aminocephalosporanic acid using whole cell enzyme of Xanthomonas citri (IFO 3835). Some optimal conditions for cephaloglycin synthesis were investigated, and yield improvements for its production by several methods were attempted. Using the whole cell enzyme system, the reaction kinetic model for cephaloglycin synthesis is proposed, and the kinetic constants for D-${\alpha}$ -phenylglycine methyl ester hydrolysis, cephaloglycin synthesis, and cephaloglycin hydrolysis were determined. The $K_m$ values of D-${\alpha}$-phenylglycine methyl ester, 7-aminocephalosporanic acid, and cephaloglycin were 11 mM, 24 mM, and 167 mM, and $K_i$ value of D-${\alpha}$-phenylglycine was 15 mM, respectively. The pattern of product inhibition was found to be competitive one.

• Journal of Microbiology and Biotechnology
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• 제11권2호
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• pp.329-332
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• 2001

It has been known that, in enzymatic synthesis of cephalexin, the conversion yield was reduced by high loading of ampicillin acylase. In order to elucidate this phenomena, pH-controlled synthesis of cephalexin was examined using a purified Acetobacter turbidans acylase. When the pH of the reaction mixture was maintained at $6.20{\pm}0.04$, the reduction of the maximal conversion rate was not observed even with high enzyme loading. The kinetic parameters also suggest that pH drop during the enzymatic synthesis of cephalexin was mainly attributed to the rapid hydrolysis of D-${\alpha}$-phenylglycine methyl ester to D-${\alpha}$-phenylglycine, rather than the disappearance of 7-amino-3-deacetoxycephalosporanic acid for cephalexin synthesis. At higher molar ratio of two substrates, [D-${\alpha}$-phenylglycine methyl ester]/[7-amino-3-deacetoxycephalosporanic acid], the conversion rate was also elevated under pH-controlled enzymatic synthesis, which implies that the main reason for the pH drop is due to the production of D-${\alpha}$-phenylglycine methyl easter, the effect of a water-methanol cosolvent system on the ester, the effect of a water-methanol cosolvent system on the conversion profile was also examined. Even the though the conversion rate was increased in 10% methanol solution, a higher than 16% methanol in the reaction mixture caused an inactivation of enzyme.

• Archives of Pharmacal Research
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• 제13권3호
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• pp.257-260
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• 1990

Hantzch's type reaction of methyl acetopyruvate (2a), methyl 3-aminocrotonate (3) and 3-nitrobenzaldehyde (4) led to dimethyl 3-acetyl-6-methyl-4-(3'-nitrophenyl)-2, 5-dicarboxylate (5a) and methyl 2, 6-dimethyl-5-(1', 2'-dioxo-2'-methoxyethyl)-4-(3' nitrophenyl)- 2, 5-dicarboxylate (5a) and methyl 2, 6-dimethyl-5-(1', 2'-dioxo-2'methoxyethyl_4-(3' nitrophenyl)1, 4-dihydropyridine-3-carboxylate (6a) in 26.7 and 9.2% yield, respectively. On the other hand, methyl 2, 60dimethyl-4-(3'-nitrophenyl)-1, 4-dihydropyridine 3-carboxylate (9) was acylated by ethyl oxaly chloride to give methyl 2, 6-dimethyl-5-(1', 2'-dioxo-2'-ethoxyethyl)-4-(3'-nitrophenyl)-a, 4-dihydropyridine-3-carboxylate (6b) in 76.8% yield.

• Journal of Microbiology and Biotechnology
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• 제14권1호
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• pp.62-67
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• 2004

The biosynthesis of cephalexin was carried out in the aqueous two-phase systems using penicillin acylase as a catalyst, and 7-aminodeacetoxicephalosporanic acid (7-ADCA) and phenylglycine methyl ester (PGME) as substrates. 20% PEG400-l7.5% ${(NH_4)}_2SO_4$ containing 0.5 M NaCl and 1.5 M methanol aqueous two-phase systems (ATPS) were selected as reaction medium, and 53% product yield was obtained using immobilized penicillin acylase as a catalyst. 20% PEG400-l5% $MgSO_4$ ATPS was also used for the synthesis of cephalexin, and 60-62% product yield was obtained by using free penicillin acylase as a catalyst. When batch reactions were repeated in the ATPS, the cephalexin yields decreased during the reactions due to deactivation, loss, and product inhibition of penicillin acylase. The effect of different ratio of phenylglycine methyl ester to 7-ADCA on the product yield was investigated, and high cephalexin yield was obtained at a high molar ratio.

• 생명과학회지
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• 제14권1호
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• pp.91-97
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• 2004

앞선 연구의 구조적 특성을 근거로 하여, 한 분자내에 MES 유발경련에 작용하는 cyclicimide의 구조를 포함하면, 그들의 구조가 경련 유발 수용체들에 상호 보완적으로 작용, MES및 PTZ유발 경련에 모두 작용할 수 있는 적용 범위가 넓은 항경련성 화합물이 될 수 있을 것으로 생각하여 N-acyl-$\alpha$-aminosuccinimide 1과 N-acyl-$\alpha$-aminoglutar- imide 2 유도체를 합성하였다. 먼저 (R)-2-benzyloxy carbonylamino-succinic acid 3을 출발 물질로 하여 N-acyl-a-aminosuccinimide 1 유도체인 (R)-Benzoic acid 4-benzyloxycarbonyl-amino-2-oxo-pyrrolidin-l-yl ester 6a, (R)4-nitro-benzoic acid 4-benzyloxycarbon-ylamino-2-oxo-pyrrolidin-1-yl ester 6b, (R)-4-nitro-benzoic acid 4-benzyloxycarbonylamino-2-oxo-pyrrolidin-1-yl ester 6c, 그리고 (R)-propionic acid 4-benzyloxycarbonylamino-2-oxo-pyrrolidin-1-yl ester 64를 합성하였다 또한 (R)-3-car-bobenzyloxy-aminoglutarrnic acid 7를 출발물질로 하여 N-acyl-$\alpha$-aminoglutarimide 2유도체인 (R)-(3-Benzyloxycarbonyl-amino-2,6-dioxo-piperidin-1-yloxy)-acetic acid methyl ester 10a, (R)-(3-benzyloxyarbonylamino-2,6-dioxo-piperidin-1-yloxy)-acetic acid ethyl ester l0b, 그리고 (R)-2-(3-benzylox-ycarbonylanino-2,6-dioxo-piperidin-1-yloxy)-propionic acid methyl ester l0c를 합성하였다. 합성된 화합물 6a, 6b, 6c, 6d, 10a, lOb, l0c에 대한 활성평가는 각 단계별 MES test와 PTZ test의 항경련 활성 시험 방법을 가지고 실험할 예정이다.

• KSBB Journal
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• 제13권6호
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• pp.706-717
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• 1998

과당계열 배당체인 메틸프룩토시드를 반응출발문질로하여 과당계열 당 지방산 에스테르인 메틸프룩토시드 올레산 모노 및 디에스테르를 효소적 용매 및 무용매공정에 의하여 합성하였다. 용매공정으로부터 머틸프룩토시드 올레산 모노에스테르를 합성한 결과, 최적 상용용매로는 2-메틸-2-프로관올이 우수하게 나타났으며 매틸프룩토시드의 용해도는 $60^{\circ}C$애서 400g/L이상에 상당하였다. 최적반응조건을 검토한 결과, 에틸프룩토시드 올레산의 최적올비 3.1, 에틸프룩토시드의 최적 초기농도 200g/L, Novozym 435의 최적 촉매함량 1%(w!v), 반응온도 $60^{\circ}C$에서 반응시간 8시간만에 70%의 평 형 젠화율애 도달하였으며 12.6g/L-hr의 생산성으로 매렐프룩토시드 올레산 모노에스테프 블 생싼할 수 았었다. 그리고, 무용매공정에서 메틸프룩토시드 올레산 디에스터르를 합생한 결과, 메틸프룩토시드와 올레산의 최적돌에 l.2, Novozym 435의 최적 촉매함령, 10%(w/w), 반응온도 $70^{\circ}C$, 진공도 20 - 200mmHg 에서 반응시간 10시간만에 95%이상의 전화율로 140g;L-hr의 생산성으로 메틸프룩토시드 올레산 디에스테르를 생산할 수 있었다.

• 한국응용과학기술학회지
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• 제23권1호
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• pp.12-18
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• 2006

The transesterification of vegetable oils into Biodiesel at $60^{\circ}C$ was performed on the rotary viscometer. The overall yield(%) of fatty acid methyl ester from canola oil at optimum conditions was 95%. The viscosities of fatty acid methyl esters were predicted by Orrick and Erbarr's model. The overall yield increased as the viscosities of fatty acid methyl esters decreased. The limiting molar ratio of methanol to oil appeared to be 1:5. The content of sodium hydroxide as the optimum catalyst appeared to be 0.5wt%.