• Bulletin of the Korean Chemical Society
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• v.13 no.4
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• pp.407-413
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• 1992

The chromatographic separation of the stereoisomers of the N-(3,5-dinitrobenzoyl) derivatives of fifteen dipeptide methyl esters and nine dipeptide alkyl esters was investigated on three different chiral stationary phases derived from N-acylated ${\alpha}-arylalkylamines$. Two of these CSPs contain second stereogenic centers. These secondary stereogenic centers of CSPs were proposed to provide secondary effects in terms of chiral recognition. From the elution orders of the four dipeptide stereoisomers and the separation factors of the enantiomeric pairs of the N-(3,5-dinitrobenzoyl) derivatives of the dipeptide alkyl esters having different alkoxy substituents, it was proposed that the intercalation of the alkoxy substituents of dipeptide derivatives between the connecting arm of CSPs may control the magnitude of chiral separations of dipeptide derivatives.

• Journal of the Korean Applied Science and Technology
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• v.16 no.1
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• pp.83-94
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• 1999

Glycoside fatty acid esters were synthesized by lipase-catalyzed glycosylation of fatty acids with methyl glycoside in solvent and solvent free process. Optimum condition of solvent process using 2-methyl-2-propanol were : moral ratio of methyl glycoside to fatty acid 1:3: initial concentration of methyl glycoside 50g/l:enzyme(immodilized lipase Novozym 435 from Candidia antarctica) content 1%(w/v) : desiccant content 9%(w/v); reaction temperature $60^{\circ}C$: reaction time 10hrs. The yield of 99% was obtained. Solvent-free process was carried out in total absence of solvent at $70^{\circ}C$ under reduced pressure, 5-20mmHg. To give meximum yield of 99% at the optimum condition of molar ratio of methyl glycoside to fatty acid 1:3, enzyme content 10%(w/w), and reaction time 10hrs. The glycosylation reactivity of different glycosylation agents were sequent to $Methyl-{\beta}-D-fructofuranoside$. $Methyl-{\beta}-D-glucopyranoside$. $Methyl-{\beta}-D-fructofuranosi$ de, and $Methyl-{\alpha}-D-glucopyranoside$.

• Korean Journal of Food Science and Technology
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• v.29 no.6
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• pp.1144-1150
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• 1997

Volatile flavor components of soybean koji kochujang made from a glutinuous rice by improved method were analyzed by using a purge and trap method during fermentation, and identified with GC-MSD. Fifty-six volatile flavor components including 16 alcohols, 15 esters, 7 acids, 4 aldehydes, 5 alkanes, 3 ketones, 1 benzene, 1 alkene, 2 phenol and 2 others were found in improved kochujang. The number of volatile flavor components detected immediately after making kochujang were 32 and increased to 46 components after 30 day of fermentation. The most number 55 of volatile flavor components were found after 90 day of fermentation. Thirty-one kinds of volatile flavor components were commonly found through the fermentation period 9 alcohols such as 2-methyl-1-propanol, ethanol, 3-methyl-1-butanol, 8 esters such as methyl acetate, ethyl acetate, 2-methylpropyl acetate, 3 aldehydes such as butanal, acetaldehyde, furfural and 11 othesrs. Although the various types of peak areas (%) of volatile flavor components were shown in kochujang during the fermentation days, ethanol. ethyl acetate, ethyl butanoate, 2-methylpropyl acetate, 2-methyl-1-propanol and 3-methyl-1-butanol were mainly detected during fermentation. Those might be the major volatile flavor components in kochujang made by improved method. Peak area of ethanol was the highest one among the volatile flavor components at immediately after mashing and 90 day while ethyl acetate showed the highest Peak area after $30{\sim}60$ day of fermentation and 3-methyl-1-butanol showed the highest peak area after $120{\sim}150$ day of fermentation.

• YAKHAK HOEJI
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• v.28 no.1
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• pp.25-27
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• 1984

Some $\betha$-lactam antibiotics-penicillins and cephalosporins-were determined by gas chromatography (GC) with flame photometric detector (FPD) which was selective and sensitive to sulfur-containing compounds. Methyl ester derivatives of carboxyl group in $\betha$-lactam antibiotics were prepared using 0.5Mmethyl iodide in methylene chloride and were taken for gas chromatography with 0.9% or 0.6% QF-1 on Chromosorb WAW-DMCS. We have found that it is possible to determine methyl esters of $\betha$-lactam antibiotics by GC/FPD.

• Journal of the Korean Applied Science and Technology
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• v.17 no.2
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• pp.94-98
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• 2000

Sodium N-acyl N-methyl taurates were synthesized by effectual acylation of fatty acid ethyl esters $C(C_{12}{\sim}C_{18})$ and N-methyl taurine. All the surface activities including krafft point, solubility, interface tension, foaming power, lime-soap dispersing ability and detergency were measured, and cmc was evaluated in dilute aqueous solution.

• Journal of the Korean Chemical Society
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• v.38 no.9
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• pp.682-686
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• 1994

New synthetic method of aminophosphonic acids by the amination of organoboranes containing phosphorus was developed. Thus, the hydroboration of diethyl 2-propenylphosphonate, diethyl 2-methyl-2-propenyl-phosphonate, diethyl 3-butenylphosphonate with borane-THF, followed by amination of the resulting organoboranes with hydroxylamine-O-sulfonic acid gave diethyl 3-aminopropylphosphonate, diethyl 3-amino-2-methyl-2-propylphosphonate and diethyl 4-aminobutylphosphonate, respectively. 3-Aminopropylphosphonic acid and 4-aminobutylphosphonic, acid were obtained by the hydrolysis of the corresponding esters, respectively.

• Archives of Pharmacal Research
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• v.24 no.6
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• pp.503-507
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• 2001

trans-Metanicotine, a subtype (${\alpha}_4{\beta}_2$)-selective ligand for neuronal nicotinic acetylcholine receptor, is under clinical phase for Alzheimer's disease. An efficient synthetic route for ($\pm$)-methyl-(1-aryl-4-pyridin-3-yl-but-3-enyl)-am ices, derivatives of tracts-metanicotine, was explored. Allylation reaction of aryl aldimines with allylmagnesium bromide in THF gave ($\pm$)-methyl-(1-aryl-but-3-enyl)-amines. Protection of the amines with the Boc group and following Heck reaction of the N-Boc amines with 3-bromopyridine gave ($\pm$)-methyl-(1-aryl-4-pyridin-3-yl-but-3-enyl)-carbamic acid tert-butyl esters. Deprotection of the N-Boc group in aqueous 1 N-HCI solution gave the titled amines in good yields. Thus, trans-metanicotine analogues modified at the ${\alpha}-position$ of the methylamino group with amyl groups were obtained in 5 steps.

• Korean Journal of Food Science and Technology
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• v.20 no.5
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• pp.718-723
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• 1988

A yeast strain producing fruity-floral aroma was isolated from soil and identified as Hansenula saturnus var. saturnus. Glucose was found to be the best carbon source and sodium nitrate or phenylalanine as nitrogen source in terms of the nature and the intensity of the aroma produced by the isolated yeast. Seventeen compounds, mainly esters and alcohols, were identified in the ether-pentane extract of the culture broth by gas chromatography and/or coupled gas chromatography-mass spectrometry. Ethyl alcohol, isobutyl alcohol, isoamyl alcohol, phenethyl alcohol and their acetate esters together with ethyl caprylate were the major compounds in the aroma concentrate. Three unusual compounds, dibutyl disulfide, 3-methyl pentanoic acid and methyl pentanoate were also tentatively identified in the culture broth of the isolated yeast.

• Journal of the Korean Applied Science and Technology
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• v.32 no.1
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• pp.72-77
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• 2015

In this study, anti-foaming agents of a fatty acid methyl esters was synthesized and confirmed by FT-IR and $^1H-NMR$ spectroscopy. Synthesized material of characteristic of -C=O group having a $1740cm^{-1}$ and -C-O group $1175cm^{-1}$ peak by using FT-IR, and it was confirmed that k. Surface tensions were measured by surface tensiometer CBVP-43. Their surface tension values was 17.7 to 21 dyne/cm. Anti-foaming abilities in the SLS solution was measured through the Ross-Miles method. Performance of the 4 type of anti-foaming agent was determined and the best anti-foaming agent was prepared using stearic acid methyl.

• Journal of Life Science
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• v.16 no.7 s.80
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• pp.1243-1249
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• 2006

Volatile flavor compounds in commercial crab-like flavorants were compared by mean of solid phase microextraction(SPME) and liquid continuous extraction (LLCE)/GC/MSD methods. A total of 86 volatile flavor compounds were detected. Of these, 71 were positively identified consisting mainly of sulfur-containing compounds (13), aldehydes (3), ketones (2), esters (26), alcohols (5), aromatic compounds (3), terpenes (8), acids (2) and miscellaneous compounds (9). SPME method was more effective than LLCE method in detection of volatile components in commercial crab-like flavorants. Eight S-, N-containing compounds such as dimethyl sulfide, dimethyl disulfide, dipropyl disulfide, 3-(methylthio)propyl acetate, 3-(methylthio) propanal, 3-(methylthio) propanol, 2-methyl-3-(methylthio) pyrazine and 2-methyl-5-(methylthio) pyrazine, 8 esters such as styrallyl acetate, ethyl acetate, isoamyl acetate, benzyl acetate, ethyl pentanoate, butyl pentanoate, isoamyl pentanoate and furfuryl acetate were considered as major components in crab-like flavorants.