• Korean Journal of Pharmacognosy
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• v.17 no.1
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• pp.85-90
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• 1986

It has been elucidated that magnolol and honokiol, isolated from the stem bark of Magnolia obovata, had potent antibacterial activity against a cariogenic bacterium Streptococcus mutans. They also show a significant antibacterial activity against Bacillus anthracis, which causes malignant pustule and woolsorter disease in human. Some hydroxybiphenyl derivatives are synthesized from starting materials, phenylphenols and biphenols by means of Claisen's rearrangement and Elb's method to develop more potent antibacterial chemicals and to investigate the structure-activity relationships. The introduction of allyl groups to the aromatic rings of starting materials shows increase of antibacterial activities, but the number and positions of them do not effect their activities. Furthermore, the introduction of hydroxy group to aromatic rings also increases the activity.

• Archives of Pharmacal Research
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• v.14 no.1
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• pp.41-43
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• 1991

For the purpose of survey of the antibacterial activity against a cariogenic bacterium Streptococcus mutans OMZ 176 with the introduction of hydroxyl and allyl groups to o-phenylphenol (Fig. 2, 1), 4-hydroxy-o-phenylphenol (2), and 3,6-diallyl-4-hydroxy-o-phenylphenol (4) were synthesized, sucessively. The synthesized compounds, 2 and 4 showed more potent antibacterial activity than the starting material, 1. The hydroxyl group was supposed to the essential element for the antibacterial activity and the introduction of allyl group to phenolic ring to be another element to increase the activity.

• Bulletin of the Korean Chemical Society
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• v.29 no.5
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• pp.993-997
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• 2008

Two directional ring-closing metathesis (RCM) was applied successfully to the synthesis of 4'-vinylated carbocyclic nucleoside analogues from the trivinyl intermediate 12, which was readily made using a sequential Claisen rearrangement and ring-closing metathesis (RCM) starting from Weinreb amide 5. An antiviral evaluation of the synthesized compounds against various viruses such as HIV, HSV-1, HSV-2 and HCMV revealed that the guanine analogue 20 have moderate anti-HIV activity in the MT-4 cell line ($EC_{50}$ = 10.2 $\mu$ M).

• Bulletin of the Korean Chemical Society
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• v.30 no.11
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• pp.2626-2630
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• 2009

2'($\beta$)-Hydroxymethylated adenosine is a potent and selective inhibitor of hepatitis C virus (HCV) replication. It targets the RNA-dependent RNA polymerase of HCV, NS5B. Synthesis and antiviral evaluation of carbocyclic versions are described. The cyclopentene intermediate ($9\beta$) was successfully synthesized through sequential Johnson-Claisen orthoester rearrangement and ring-closing metathesis (RCM). Coupling of bases via a Pd(0) catalyst, selective dihydroxylation, and desilylation yielded the target nucleoside analogues. The compounds 17 and 18 were assayed for their ability to inhibit HCV RNA replication in a subgenomic replicon Huh7 cell line and showed moderate antiviral activity with toxicity up to 20.0 and 24.7 ${\mu}g/mL$, respectively.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.179.3-179.3
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• 2003

Natural histrionicotoxin, a substance isolated from the skins of the "arrow poison frog" and its fully hydrogenated derivative, perhydrohistrionicotoxin (pHTX), have been the subject of synthetic investigation because of their important neurophysiological activity and a unique framework. In this work, we could obtained the appropriately functionalized spiropiperidine compound as a formal precursor of perhydrohistrionicotoxin. An important feature of this synthesis is the creation of a stereogenic center by using Ireland-Claisen Rearrangement, and Ring-Closing Metathesis (RCM).sis (RCM).

• Korean Chemical Engineering Research
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• v.43 no.6
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• pp.662-667
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• 2005

2,3-Dihydrobenzofuran derivatives, important intermediates of medicines and agricultural chemicals, were prepared from aryl methallyl ethers over MCM-41 mesoporous material catalysts. Two mesoporous materials with Si/Al mole ratios of 40 and 50 were prepared to investigate the effect of acid site concentration on their catalytic activities. Aryl methallyl ethers with various substituents on their benzene rings were used to investigate the effect of electron density on benzene ring on the conversion of the ethers and the yield of 2,3-dihydorbenzofuran derivatives. The catalyst with a high acid site concentration showed high conversions, but it is difficult to correlate the yield of the derivatives with the acid site concentration. The increase in the electron density of the benzene ring by introducing electron-donating groups accelerated Claisen rearrangement reaction, resulting in the enhanced yield of the derivatives. On the other hand, the decrease in the electron density by introducing electron-attracting groups accelerated the cracking reaction of aryl methallyl ether by acid catalysts, producing phenol derivatives rather than 2,3-dihydrobenzofuran derivatives.