• Title/Summary/Keyword: Electrophilicity

Search Result 32, Processing Time 0.015 seconds

Effect of the Aryl Substituent on Antitumor Activity of 2-Substituted-1,4-dihydroxy-9,10-anthraquinones and 2-Substituted-anthracene-1,4,9,10-tetraones

  • Nam, Nguyen-Hai;Jin, Guang-Zhu;Tam, Mai-Ngoc;Ahn, Byung-Zun
    • Archives of Pharmacal Research
    • /
    • v.22 no.6
    • /
    • pp.592-607
    • /
    • 1999
  • 2-(1-Aryl-1-hydroxymethyl)-and 2-aroyl-DHAQ derivatives (DHAQ, 1,4-dihydroxy-,10-anthraquinone), and 2-(1-aryl-1-hydroxymethyl)-ATO derivatives (ATO, anthraceneactivity (T/C 125~128%), though their cytotoxicity was not further improved compared to that of 2-(1-aryl-1-dydroxymethyl)-1,4-dihydroxy-9,10-anthraquinones. They manifested no correlation between the cytotoxicity and the antitumor activity. In case of 2-[1-hydroxy-1-(4-propylphenyl)-methyl]-ATO, the most bioactive one in viv-1,4,9,10-tetraone) were synthesized and their antitumor activities were determined. 2-(1-Aryl-1-hydroxymethyl)-DHAQ derivatives showed a stronger cytotoxicity compared to the series of 2-(1-hydroxyalkyl)-1,4-dihydroxy-9,10-anthraquinone derivatives. It was suggested that the presence of aryl group at the side chain accelerated the bioreductive activation leading to cell death. 2-Aroyl-DHAQ derivatives, despite their higher electrophilicity, revealed smaller cytotoxicity and antitumor activity (expressed by T/C value) than 2-(1-aryl-1-hydroxymethyl)-DHAQ derivatives. Thus, no consistent relationship between the electronic effect on aromatic side chain and the cytotoxicity was observed. ATO series exhibited a higher antitumor o among the same series, it showed an $ED_{50}$ value of 10.2 mg/mL and a T/C value of 218%. It is assumed that the anthrancene1,4,9,10-tetraones after uptake into cellular tissues might be transformed to a cytotoxic metabolite(s).

  • PDF

Effects of Divalent Cations on Alkaline Hydrolysis of Poly(ethylene terephthalate) Fabric (2가 양이온이 폴리에틸렌 텔레프탈레이트 직물의 알칼리 가수분해에 미치는 영향)

  • Dho, Seong Kook;Choi, Chin Hyup
    • Textile Coloration and Finishing
    • /
    • v.7 no.4
    • /
    • pp.61-73
    • /
    • 1995
  • Inorganic salts have negative or positive effects on the rates of many chemical reactions and also the rates of acidic and alkaline hydrolysis of carboxylic esters. The direction of salt effects on the hydrolysis of ester depends on the charge of esters. It is expected that the rate of the alkaline hydrolysis of Poly(ethylene terephthalte)(PET), polymeric solid carboxytic polyester with carboxyl end group at the polymer end, is also influenced by inorganic salts. In the present work, to clarify the effect of divalent cations on the alkaline hydrolysis of PET, many salts with divalent cations like $MgCl_{2},CaCl_{2},SrCl_{2},BaCl_{2},$ were added to the aqueous alkaline solutions. Then PET was hydrolyzed with aqueous NaOH solution having many salts under various conditions. Some conclusions obtained from the experimental results were summarized as follows. Many salts with various divalent cations increased or decreased the reaction rate of alkaline hydrolysis of PET depending on their electrophilicity, hydration property, ability of ion pair formation, solubility, and the degree of interactions between divalent cations and anions, etc. The hydrolysis was interrupted in the order of $Ca^{+2} and was generally accelerated in the order of $Ba^{+2}. It was inferred from the increase in ΔS$^*$and the decrease in the ΔG$^*$that the divalent cations $Sr^{+2}$ and $Ba^{+2}$attracted by PET increased the collision frequency between carbonyl carbon and $OH^{-}$ion and then accelerated the reaction rate. $Mg^{+2}$and $Ca^{+2}$decreased the reaction rate because of their strong interaction with $OH^{-}$.

  • PDF