• Toxicological Research
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• v.33 no.4
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• pp.265-272
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• 2017

Aryl hydrocarbons such as 3-nitrobenzanthrone (NBA), 4-aminobiphenyl (ABP), acetylaminofluorene (AAF), benzo(a)pyrene (BaP), and 1-nitropyrene (NP) form bulky DNA adducts when absorbed by mammalian cells. These chemicals are metabolically activated to reactive forms in mammalian cells and preferentially get attached covalently to the $N^2$ or C8 positions of guanine or the $N^6$ position of adenine. The proportion of $N^2$ and C8 guanine adducts in DNA differs among chemicals. Although these adducts block DNA replication, cells have a mechanism allowing to continue replication by bypassing these adducts: translesion DNA synthesis (TLS). TLS is performed by translesion DNA polymerases-Pol ${\eta}$, ${\kappa}$, ${\iota}$, and ${\zeta}$ and Rev1-in an error-free or error-prone manner. Regarding the NBA adducts, namely, 2-(2'-deoxyguanosin-$N^2$-yl)-3-aminobenzanthrone (dG-$N^2$-ABA) and N-(2'-deoxyguanosin-8-yl)-3-aminobenzanthrone (dG-C8-ABA), dG-$N^2$-ABA is produced more often than dG-C8-ABA, whereas dG-C8-ABA blocks DNA replication more strongly than dG-$N^2$-ABA. dG-$N^2$-ABA allows for a less error-prone bypass than dG-C8-ABA does. Pol ${\eta}$ and ${\kappa}$ are stronger contributors to TLS over dG-C8-ABA, and Pol ${\kappa}$ bypasses dG-C8-ABA in an error-prone manner. TLS efficiency and error-proneness are affected by the sequences surrounding the adduct, as demonstrated in our previous study on an ABP adduct, N-(2'-deoxyguanosine-8-yl)-4-aminobiphenyl (dG-C8-ABP). Elucidation of the general mechanisms determining efficiency, error-proneness, and the polymerases involved in TLS over various adducts is the next step in the research on TLS. These TLS studies will clarify the mechanisms underlying aryl hydrocarbon mutagenesis and carcinogenesis in more detail.

• Bulletin of the Korean Chemical Society
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• v.33 no.10
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• pp.3321-3330
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• 2012

The complexation characteristics of mixed [2 + 2'] calix[4]aryl derivatives (3 and 4) with alkali metal cations were investigated by the mPW1PW91 (hybrid HF-DF) calculation method. The total electronic and Gibbs free energies of the various complexes (cone, partial-cone, 1,2-alternate, and 1,3-alternate) of sodium and potassium cations with 3 and 4 were analyzed and compared. The structures of the endo- or exo-complexes of the alkali metal cation with the host 3 were optimized using the mPW1PW91/6-31G(d) method, followed by mPW1PW91/6-311+G(d) calculations. The structures of the endo- or exo-complexes of the alkali metal cation with the host 4 were optimized using the mPW1PW91/6-31G(d,p) method. The mPW1PW91 calculated relative energies of the various conformations of the free hosts (3 and 4) suggest that the cone conformers of 3 and 4 are the most stable. The mPW1PW91calculations also suggest that the complexation efficiencies of the sodium ion with hosts 3 and 4 are about 24 and 27 kcal/mol better than those of the potassium ion, respectively. These trends are in good agreement with the experimental results. The exo-complexation efficiencies of the sodium ion toward the conformers of hosts 3 and 4 are roughly 14 and 17 kcal/mol better than those for the endo-$Na^+$-complexes of 3 and 4, respectively. The exo-complexation of the cone isomer of 3 with cation could be confirmed by the differences of the diagnostic C=O bands in the free host and its complex's IR spectra.

• Bulletin of the Korean Chemical Society
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• v.26 no.2
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• pp.343-344
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• 2005

• Bulletin of the Korean Chemical Society
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• v.13 no.5
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• pp.462-463
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• 1992

• Bulletin of the Korean Chemical Society
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• v.22 no.10
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• pp.1163-1166
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• 2001

• Bulletin of the Korean Chemical Society
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• v.20 no.2
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• pp.232-236
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• 1999

• Bulletin of the Korean Chemical Society
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• v.20 no.10
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• pp.1229-1231
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• 1999

• Bulletin of the Korean Chemical Society
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• v.22 no.7
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• pp.761-764
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• 2001

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.346.2-346.2
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• 2002

Recently, several branched-nucleosides have been synthesized and evaluated as potent antitumor or antiviral agents. Among them, 4'${\alpha}$--C-ethenyl and 4'${\alpha}$-C-ethynyl nucleosides which having an additional double or triple bond at 4'-position were reported to be as potent antiviral and anlitumor activities. Encouraged by these interesting structures and antiviral activities, it was determined to synthesize novel classes of nucleosides comprising branched carbocyclic nucleosides with an additional aryl group at 4'${\alpha}$-position using versatile reiterative three-step sequences from simple acyclic precursor '2-hydroxyacetophenone. Our efforts toward the synthesis of novel nucleosides analogues are reported herein.

• Journal of the Korean Chemical Society
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• v.40 no.9
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• pp.615-622
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• 1996

(Benzotriazol-1-yl)arenesulfonylalkanes, 2a, 2b, 3a and 3b, were prepared by lithiation of 1-(benzotriazol-1-yl)arenesulfonylmethanes followed by reaction with alkyl iodides. Very bulky molecules such as 1,1-di(benzotriazol-1-yl)-1-aryl-1-thiophenoxymethanes 5, 1,1-di(benzotriazol-1-yl)-1-thiophenoxymethane 9a and 1,1-di(benzotriazol-1-yl)-1,1-dithiophenoxymethane 9b were synthesized. 1,1-Di(benzotriazol-1-yl)-1-benzenesulfoxymethane 10a and 1,1-di(benzotriazol-1-yl)-1-benzenesulfonylmethane 10b were also synthesized by the oxidation of compound 9a, while oxidation of sulfide group on compound 5 and 9b by m-CPBA were not successful. On the other hand, pyrolysis and hydrolysis of 3-(benzotriazol-1-yl)-3-toluenesulfonylpentane 3b gave 3-toluenesulfonyl-2-pentene 11 and diethyl ketone 13a, respectively, which means there are both C-N and C-S bond cleavages.