• YAKHAK HOEJI
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• v.57 no.5
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• pp.316-322
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• 2013

The new pyridazinone analogs were synthesized for development of candidates to retain anticancer activity. Various 6-substituted pyridazin-3(2H)-ones were prepared from the pyridazinyl chloride 3a~d via endothermic nucleophilic substitution with hydroxide ion as nucleophile for 2~48 h. Pyridazinyl chloride 3a~d could be converted to hydroxypyridazines (or pyridazin-3(2H)ones) using 1~5 equivalents of water (or 1 equivalent of sodium hydroxide) at reflux in DMF. The tautomerism of lactim form to lactam form was also accomplished in pyridazine derivatives. Formation of pyridazinones 10 was undertaken with stirring using sodium hydroxide at reflux in DMF for 2 h. Synthetic compounds were identified using NMR spectrum.

• Bulletin of the Korean Chemical Society
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• v.16 no.9
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• pp.827-831
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• 1995

Kinetic studies on the reactions of five secondary acylic alkyl arenesulfonates with anilines are carried out in acetonitrile at 65.0 ℃. The magnitude of ρXZ determined (ρXZ=0.12-0.13) is slightly greater than that for the alicyclic series (ρXZ=0.11) under the same experimental condition. Ab initio MO results are found to support the slightly tighter transition state expected from the greater magnitude of ρXZ for the acyclic series. Despite the small variations, the magnitude of ρXZ and the theoretical transition state tightness remain relatively constant for the secondary carbon centers. Secondary kinetic isotope effects involving deuterated aniline nucleophiles show a successively smaller kH/kD(<1.0) value for a more sterically crowded reaction center carbon. This is in accord with the later transition state for bond-making predicted by the Bell-Evans-Polanyi principle for the more endothermic nucleophilic substitution reaction. Further support is provided by the results of the AM1 MO calculations on the reactions of secondary alkyl benzenesulfonates with chloride nucleophile.

• Bulletin of the Korean Chemical Society
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• v.30 no.9
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• pp.2051-2056
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• 2009

The rate constants of alkaline fading of malachite green ($MG^+$) was measured in the presence of nonionic (TX-100), cationic (DTAB) and anionic (SDS) surfactants. This reaction was studied under pseudo-first-order conditions at 283∼303 K. The rate of fading reaction showed noticeable dependence on the electrical charge of the used surfactants. It was observed that the reaction rate constants were increased in the presence of TX-100 and DTAB and decreased in the presence of SDS. According to Hughs-Ingold rules for nucleophilic substitution reactions, the electric charge of MG/surfactant compound along with decrease in dielectric constant of $MG^+$ micro-environment in this compound varies the rate of fading reaction. Binding constants of surfactant molecules to $MG^+$ were calculated using cooperativity, pseudo-phase ion exchange and classical models and the related thermodynamic parameters were obtained by classical model. The results show that the binding of $MG^+$ to TX-100 is exothermic and binding of $MG^+$ to DTAB and SDS in some concentration ranges of the used surfactants is endothermic and in the other ones is exothermic.