• 한국철도학회논문집
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• 제14권2호
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• pp.116-120
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• 2011

현재 초고속 자기부상열차시스템에 적용하고 있는 위치검지기술은 불연속적으로 열차위치를 파악하는 절대위치검지기술과 연속적으로 열차의 위치를 파악하는 상대위치검지기술로 구분된다. 본 논문에서는 대표적인 초고속자기부상열차인 독일 Transrapid에 적용된 절대위치검지장치의 구조와 수치모델을 분석하고, Transrapid에 적용된 절대위치검지장치와 유사한 구조를 가지는 절대위치검지장치의 인식구조별 모델을 설계하고 시뮬레이션을 통해 설계한 모델의 적합성을 검증하고 최적의 절대위치검지장치 구조를 제안한다.

• Bulletin of the Korean Chemical Society
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• 제7권2호
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• pp.106-108
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• 1986

Exciton chirality method was applied for the determination of absolute configuration of panaxynol, a poly-yne compound from Panax ginseng roots for the first time. The circular dichroic spectra of panaxynol benzoates show the negative chirality at ${\lambda}_{ext}$, indicating the S configuration of C-3 chiral center.

• Bulletin of the Korean Chemical Society
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• 제30권2호
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• pp.415-418
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• 2009

Concerned with ambiguous stereochemistry assignment of natural (+)-glabridin, absolute configurations of (${\pm}$)-glabridin enantiomers were studied with synthetic glabridin. Synthetic glabridin enantiomers were separated by semi-preparative Sumi-chiral column chromatography, and characterized by UV-Vis and NMR spectroscopy. Three-dimensional molecular structure of glabridin was obtained as equatorial Ph-3 half chair chroman ring from semi-empirical PM3 calculation, and refined by coupling constants in $^1H$ NMR spectrum. Finally, absolute configurations of two enantiomers were determined by circular dichroism spectroscopy based on the empirical helicity rules. Absolute configuration of natural (+)-glabridin was confirmed as (R)-glabridin, as known.

• Archives of Pharmacal Research
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• 제20권1호
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• pp.76-79
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• 1997

A new celastraceae alkaloid, euojaponine C has been isolated from the methanol extract of the root bark of Euonymus japonica. With the relative stereochemistry of euojaponine C established by NOESY data, the absolute stereochemistry has been determined by circular dichroism (CD) exciton chirality method. The CD of the 2, 5-bis-phenyl benzoate of triacetonide derived from the LiAlH$_{4}$, hydrolysate, euonyminol shows that the configuration of C-2 and C-5 are both R.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.241-241
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• 2006

Absolute configuration of carboxylic acids, including amino acids can be determined by circular dichroism (CD) exciton chirality method. This method employs cyclic oligopyrroles able to form stable complexes with carboxylic acids. Addition of carboxylic acids to the oligopyrroles induce CD spectrum at the macrocycle absorption region and in which the sign of the $1^{st}$ Cotton effect is determined solely by the absolute configuration of the carboxylic acid. The basicity of the pyrrole nitrogen can be controlled by macrocycle substitution thus yielding more sensitive chirality sensors.

• Biomolecules & Therapeutics
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• 제31권5호
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• pp.566-572
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• 2023

A chiral derivatization strategy with phenylglycine methyl ester (PGME) was employed to develop a straightforward method to determine the absolute configurations of N,N-dimethyl amino acids. The PGME derivatives were analyzed using liquid chromatography-mass spectrometry to identify the absolute configurations of various N,N-dimethyl amino acids based on their elution time and order. The established method was applied to assign the absolute configuration of the N,N-dimethyl phenylalanine in sanjoinine A (4), a cyclopeptide alkaloid isolated from Zizyphi Spinosi Semen widely used as herbal medicine for insomnia. Sanjoinine A displayed production of nitric oxide (NO) in LPS-activated RAW 264.7 cells.

• Archives of Pharmacal Research
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• 제10권1호
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• pp.25-28
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• 1987

(+)-Ketoprofen was obtained form resolution with (S) (+)-2-amino-1-butanol and its absolute configuration was determined to be (S) by chemical correlation with (S) (+)-ethyl hydratropate using Beckmann rearrangement as a key step.

• Archives of Pharmacal Research
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• 제14권2호
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• pp.160-164
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• 1991

The existence in nature of two isomers of 28-nortriterpenes is known. One is normal D/E cis form and the other is $17\alpha$-hydrogen D/E trans form. Since the latter cannot exist with ring D in the chair conformation, the chiroptical method is not applicable to determination of the absolute configuration. The stereochemical assignment would now be made by NMR data. Confirmation of this view could be provided by the synthesis of $3\beta, 21\beta-{dihydroxy-16-keto-28-nor-17}\alpha, \;18\beta-{olean-12-ene}$ as a model compound.

• Archives of Pharmacal Research
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• 제10권3호
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• pp.200-201
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• 1987

Frangufoline (sanjoinine-A) (1) was transformed into its epimer, sanjoinine-$Ah_1$(2) on heat treatment. Absolute configuration of (1) and (2) was determined.

• 한국응용과학기술학회지
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• 제7권1호
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• pp.107-114
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• 1990

Optical resolution of aminoalcohols had been achived efficiently by use of (R)-2,2'-dihydroxy-l,1'-binaphtholphosphoric acid as the resolving agent in various organic solvents. Racemic aminoalcohols were resolved very easily and high enantiomer yield (about 70% e,e) in THF. On the other hand, absolute configuration of resolved aminoalcohol was (R)-configuration but one of the Valinnol and Phhenylglycinol was anti-type because of sterichindrance.Optical resolution of aminoalcohols had been achived efficiently by use of (R)-2,2'-dihydroxy-1,1'-binaphtholphosphoric acid as the resolving agent in various organic solvents. Racemic aminoalcohols were resolved very easily and high enantiomer yield (about 70% e,e) in THF. On the other hand, absolute configuration of resolved aminoalcohol was (R)-configuration but one of the Valinnol and Phhenylglycinol was anti-type because of sterichindrance.