• Archives of Pharmacal Research
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• v.14 no.2
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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.

• Biomolecules & Therapeutics
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• v.8 no.1
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• pp.1-12
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• 2000

Although the first pyridazine was obtained in 1886, this heterocycle was not thoroughly investigated such isomers as pyrimidine and pyrazine especially in the field of drug development because pyridazine derivatives do not occur as natural products. Recently medicinal chemists have an growing interest in the pyridazine derivatives, since many Pyridazine derivatives were found to possess various potential therapeutic activities. In this paper sixty-eight pyridazine derivatives, which are already introduced as medicines or are being developed as drugs were classified according to their pharmacological activities, reviewed since 1955 and the relationship of structure-activities was discussed.

• Journal of the Korean Society of Tobacco Science
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• v.4 no.1
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• pp.67-71
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• 1982

4, 8, 13-Duvatriene-1, 3-viols have been identified in the cuticular lipid of fresh Sohyang (aromatic cultivar) tobacco leaves. Their $\alpha, \beta$-isomers were directly separated by SE-54 glass capillary column and identified by mass spectrometry. Gas chromatographic analysis revealed that the duvatrienediols are major components in the culticular lipid of Nicotiana Tabacum.

• Bulletin of the Korean Chemical Society
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• v.35 no.1
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• pp.273-276
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• 2014

• Journal of the Korean Chemical Society
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• v.13 no.4
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• pp.347-353
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• 1969

trans-1, 4-Dideutero-2-butenedial ditosylhydrazone has been synthesized to investigate the path of the acetylene formation in the pyrolysis of the dry lithium salt. Mass spectra showed that three isotope isomers of acetylene which might come from the strained ring compound, tricyclo[1, 1, 0, ] butane, were formed.

• Bulletin of the Korean Chemical Society
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• v.24 no.1
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• pp.109-112
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• 2003

• 산업보건소식
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• no.44
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• pp.35-35
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• 1987

앞으로 본지를 통하여 현재 쓰이고 있는 유해물의 허용한계가 어떠한 근거로 정하여졌는가를 소개하고자 한다. 허용한계에 대하여 여러가지로 소개된 바 있으나 그 근거를 알지 못하여 그 적용에 있어서 잘못이 생길 수 있다. 소개되는 내용은 미국의 ACGIH의 TLV가 결정 됨에 있어서 이용된 여러가지 문헌을 소개하고 그 내용을 간추려 보고자한다. 1966년에는 367가지의 물질에 대한 TLV가 알려져 있었고 1971 년에는 500 가지의 물질에 대하여 결정된 바 있으나 본지에서는 우리나라에서 찾아볼 수 있는 물질과 기타 중요하다고 생각되는 물질을 선택하여 소개하고자 한다.

• Bulletin of the Korean Chemical Society
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• v.34 no.2
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• pp.365-366
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• 2013

• Bulletin of the Korean Chemical Society
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• v.7 no.2
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• pp.145-147
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• 1986

Dichlororhodium(Ⅲ) complexes of a flexible quadridentate ligand, N,N'-dimethylethylenediamine-N,N'-diacetic acid (dmedda), have been prepared. Both cis-${\alpha}$ and cis-${\beta}$ isomers have been yielded in the $K[Rh(dmedda)Cl_2]$ complexes, which were characterized with elemental analyses, electronic absorption and proton nuclear magnetic resonance spectroscopic data.

• Bulletin of the Korean Chemical Society
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• v.1 no.1
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• pp.23-26
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• 1980

Direct photoisomerizations of benzalpyrrolinones yield the corresponding E-isomers via a singlet state, since no effect of oxygen on the reaction rates was observed. The Z-oxodipyrromethene was photoisomerized to the E-isomer in a degassed system. In an aerobic system the oxodipyrromethene 3 was photoisomerized at the early stage of the reaction and photooxygenated slowly at latter stage of the reaction. For bilirubin, other (possibly Z ${\to}$ E) than self-sensitizing $^1O_2$ reaction should have occurred because of the lack of a solvent effect on the self-sensitized photooxidation reaction rate at the early stage.