• Bulletin of the Korean Chemical Society
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• 제18권8호
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• pp.865-868
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• 1997

Second-order rate constants have been measured spectrophotometrically for the reactions of p-nitrophenyl phenylacetate (1) and benzoate (2) with a series of alicyclic amines in H2O containing 20 mole % DMSO at 25.0 ℃. 1 appears to be more reactive than 2 toward all the amines studied, although phenylacetic acid is a weaker acid than benzoic acid. The higher reactivity of 1 can be attributed to resonance and/or steric effect, since the ground state of 2 can be stabilized by resonance and 1 would experience less steric hindrance due to the presence of CH2 group between phenyl and C=O group. The reactivity of the amines increases with increasing their basicity. The Bronsted-type plots for aminolysis of 1 and 2 show good linearity with βnuc values of 0.81 and 0.85, respectively, indicating that the TS structures of the aminolyses of 1 and 2 are similar. Besides, the linear Bronsted plots obtained in the present system clearly suggest that there is no mechanism change for the given series of the amines and the reactions of 1 and 2 proceed in a same mechanism.

• 대한화학회지
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• 제36권3호
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• pp.446-452
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• 1992

80% acetonitrile-20% water(v/v) 용액에서 piperidine에 의한 aryl phenylacetate류의 가수분해 반응 속도를 측정하였다. 이탈되는 phnol의 치환기가 전자받개인 경우, 가수분해는 일반 염기촉매로 진행되며 $30^{\circ}C$에서 Hammett $\rho_{LG}$값은 5.28, Bronsted $\beta$값은 -2.72이었다. 이와 같이 매우 큰 Hammett 및 Bronsted 값은 이 반응이 $E1_{C}B$ 메카니즘으로 가수분해됨을 나타낸다. 한편, 전자주개 치환기의 경우는 특수 염기촉매에 의해 가수분해되며 $B_{AC}2 메카니즘이 우세하게 나타났다. Phenylacetic acid ester의 $pK_{SH}를 구하였으며, piperidine에 의한 ester 반응의 가수분해 속도 상수 $k_1$, $k_{-1)$, $k_2$도 계산하였다.

• Bulletin of the Korean Chemical Society
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• 제31권4호
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• pp.825-828
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• 2010

To classify Glycyrrhiza species, samples of different species were analyzed by $^1H$ NMR-based metabolomics technique. Partial least squares discriminant analysis (PLS-DA) was used as the multivariate statistical analysis of the 1H NMR data sets. There was a clear separation between various Glycyrrhiza species in the PLS-DA derived score plots. The PLS-DA model was validated, and the key metabolites contributing to the separation in the score plots of various Glycyrrhiza species were lactic acid, alanine, arginine, proline, malic acid, asparagine, choline, glycine, glucose, sucrose, 4-hydroxy-phenylacetic acid, and formic acid. The compounds present at relatively high levels were glucose, and 4-hydroxyphenylacetic acid in G. glabra; lactic acid, alanine, and proline in G. inflata; and arginine, malic acid, and sucrose in G. uralensis. This is the first study to perform the global metabolomic profiling and differentiation of Glycyrrhiza species using $^1H$ NMR and multivariate statistical analysis.

• 한국토양비료학회지
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• 제26권4호
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• pp.259-264
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• 1993

주요(主要) 작물(作物)이 분비(分泌)하는 알레로파지 물질(物質)의 종류(種類)와 양(量)을 동정(同定) 및 측정(測定)하여, 이들 물질(物質)이 작물(作物)에 미치는 영향(影響)을 알기위해 온실(溫室) 포트 시험으로 주요(主要) 작물(作物)을 단일(單一) 및 상호재배(相互栽培)하여 조사(調査)한 결과는 다음과 같다. 토마토, 고추, 상추, 배추, 참깨등(等) 모든 공시작물(供試作物)은 p-Coumaric acid를 분비(分泌)하였으며, 그 외 물질(物質)로는 토마토 pyrogallol, phenylacetic acid, 고추, 가지는 hydroquinone, 상추는 pyrogallol을 그리고 배추는 vanillic acid를 분비(分泌)하였다. 공시작물(供試作物)에 의해 분비(分泌)된 페놀성(性) 알레로파지 물질(物質)의 총(總) 농도(濃度)는 토마토가 $5,883{\mu}g$으로 가장 많았으며, 참깨는 $220{\mu}g/g$ 건물중(乾物重)으로 가장 적었다. 토마토-가지, 토마토-고추, 배추-가지, 배추-고추, 배추-참깨의 교호재배시(交互栽培時) 토마토와 배추의 초장(草長) 및 건물중(乾物重)은 단일재배시(單一栽培時)에 비(比)해 증가(增加)하였으나, 가지, 고추 및 참깨는 크게 감소(減少)하였다. 토마토-배추 교호재배시(交互栽培時)는 두 작물(作物) 모두 단일재배시(單一栽培時) 보다 초장(草長) 등(等)의 생장율(生長率)이 감소(減少)한 반면, 배추=상추 교호재배시(交互栽培時)는 단일재배(單一栽培)에 비(比)해 배추의 생장율(生長率)은 증가(增加)하고 상추는 감소(減少)하였다.

• Archives of Pharmacal Research
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• 제7권2호
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• pp.133-136
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• 1984

Higenamine (I), cardiotonic principle of Aconite root, was synthesized from 4-methoxy-phenylacetic acid (II) and .betha.-(3, 4-dimethoxyphenyl)-ethylamine (IV). Condensation of IV with 4-mehoxyphenylacetyl chloride (III) was followed by cyclodehydration yielding 1-(4'-methoxybenzyl)-6, 7- dimethoxy-3, 4-dihydroisoquinoline (VI). Reduction of VI to 1, 2, 3, 4-tetrahydroisoquinoline (VII) and subsequent demethylation provided desired product higenamine, 1-(4'-hydroxybenzyl)-6, 7- dihydroxy-1, 2, 3, 4, -tetrahydroisoquinoline.

• Biomolecules & Therapeutics
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• 제6권1호
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• pp.25-30
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• 1998

The roles of dopamine(DA) and N-methyl-D-aspartate(NMDA) system in the development and expression of morphine dependence were investigated by monitoring the concentrations of extracellular DA and its metabolites by in vivo microdialysis and simultaneous observation of behavioral changes in morphine dependent rats. Extracellular DA level in caudate putamen of morphine-dependent rat was decreased and the concentrations of its metabolites, dihydroxy phenylacetic acid(DOPAC) and homovanillic acid(HVA), were increased during naloxone-precipitated withdrawal. DA contents were recovered to normal levels by pretreatment of MK-801, a noncompetitive NMDA receptor antagonist, which may explain the mechanism of diminishing effect of MK-801 on withdrawal symptoms in morphine-dependent rats. MK-801(0.3 mg/tg, i.p.) induced the untoward hamful neurological signs such as ataxia and severe rotations, which may be produced by hyperactivation of dopaminergic system. These results suggest that MK-801 may inhibit the expression of mophine dependence by altering the dopamine release.

• 약학회지
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• 제47권5호
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• pp.276-282
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• 2003

For the development of new synthetic method for unnatural amino acid esters, N-aryl phenylglycine Ο-alkyl esters 4a∼i were synthesized through esterification, bromination, C-N bond formation from commercially available phenylacetic acids. An efficient and practical reaction condition for esters 2a∼c was that the starting materials 1a∼c were refluxed in absolute methanol for 3 hours with catalytic concentrated hydrosulfuric acid. In addition, bromines 3a∼c were formated for 3h in dichloromethane at rt with N-bromosuccinimide. Bromines 3a∼c were also converted to 4a∼i through substitution of arylamines during refluxing for 24 hours in ethanol with triethylamine. Interestingly, ethyl esters 5a∼c were formed via transesterification reaction when the p-sulfamylanilino group was used as a nucleophile in ethanol solvent.

• 한국연초학회지
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• 제16권2호
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• pp.172-180
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• 1994

This study was carried out to separate and identify the acidic compounds in tobacco leaves. Izmir tobacco leaves was extracted with isopropyl ether and the extract was concentrated. The concentrate was extracted with 6% NaHCO3 aqueous solution. The aqueous extract was acidified with sulfuric acid, and extracted with diethyl ether. The acidic material was fractionated on silicic acid column using a benzene-methanol mixture with a stepwise increasing methanol concentration. The resulting fractions were esterified with diazomethane, and then identified by GC, GC/MS using SPB -5 fused silica capillary column. Most of acidic compounds in Izmir tobacco leaves were elected from fraction B which was benzene-methanol(98 : 2) mixture on silicic acid column chromatography. The identified acidic compounds of Izmir tobacco leaves were 18 saturated acids, 8 unsaturated acids, 5 dicarboxylic acids, 13 aromatic acids and 7 terpenoid acids. The major acidic compounds of lzmir tobacco leaves were 2- methylbutanoic, 3-methyl butanoic, 3- methylpentanoic, hexanoic, nonanedioic, phenylacetic, benzoic, 4- methoxybenzoic, 3, 5- dimethoxybenzoic, methoxycinnamic and 3, 4- dimethoxycinnamic acid. Key Words : Izmir tobacco, Acidic compounds, GC/MS.

• 한국미생물·생명공학회지
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• 제8권1호
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• pp.33-39
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• 1980

6-APA의 생산에 사용할 Penicillin acylase를 생산하는 야생균주를 분리하여 생리화학적특성을 조사하여 Escherichia속을 동정하였다. Penicillin acylase 생산성이 가장 높은 균주를 선별하여 배양조건을 조사하고 균체를 생산하여 효소를 추출하여 효소의 반응특성을 조사한 결과는 다음과 같다. 1. 분리한 121주의 생리화학적 특성에 의해 47주가 Escherichia 속으로 동정되고 이들중 12주가 penicillin acylase 활성을 나타냈다. 2. 12주중 가장 강력한 P. acylase 활성을 나타낸 균주가 Escherichia No.11 이였다. 3. 이 균주의 효소생산조건은 탄소원은 0.3%-phenylacetic acid, 질소원은 1%-peptone과 1%-yeast extract, amino 산으로는 0.3%, L-glutamic acid가 영향을 주었다. 그리고 배지의 pH는 7.6~8.0, 배양온도는 34~38$^{\circ}C$, 배양시간은 18시간이 최적 생산조건 이였다. 4. 효소는 균체를 초음파에 의해 추출하여 원심 분리하여 상등액을 $0^{\circ}C$에서 보존하여 효소원으로 하였다. 5. 추출효소의 반응특성은 최적 반응온도는 38$^{\circ}C$, PH는 8.0이였고, 1% penicillin G를 기질로 37$^{\circ}C$에서 반응시켰을 때 4시간의 반응에서 이론식의 56%가 6-APA로 변화되었다.

• Current Research on Agriculture and Life Sciences
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• 제12권
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• pp.51-55
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• 1994

작약(芍藥)의 약(葯)으로부터 분리된 화분소포자(花粉小胞子)를 생장조절제가 첨가되지 않은 MS 배지에 배양하였을때 직접 배(胚)발생 과정을 거쳐서 소포자 유래의 배(胚)가 형성되었고, 1mg/l의 PAA가 첨가된 배지에서는 화분소포자 유래의 캘러스가 형성 되었으며 이들 캘러스를 생장조절제를 함유하지 않은 배지에 이식하였을 때 배양 7주 후에 배(胚)가 형성되었다.