• Bulletin of the Korean Chemical Society
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• v.30 no.1
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• pp.163-171
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• 2009

Few $\alpha$-Hydroxy-$\beta$-amino acids were synthesized via various nucleophilic addition of the epoxide and followed by stereoselective nucleophilic substitution reaction and eliminative cleavage of the acetal selectively in diacetal compound. One of the synthesized $\alpha$-Hydroxy-$\beta$-amino acid reacted with L-leucine methylester to give corresponding dipeptide in good yields.

• Bulletin of the Korean Chemical Society
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• v.33 no.3
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• pp.843-847
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• 2012

The nucleophilic substitution reactions of dibutyl chlorothiophosphate (4S) with substituted anilines ($XC_6H_4NH_2$) and deuterated anilines ($XC_6H_4ND_2$) are investigated kinetically in acetonitrile at $55.0^{\circ}C$. The obtained deuterium kinetic isotope effects (DKIEs;$k_H/k_D$) are primary normal ($k_H/k_D$ = 1.10-1.35). A concerted mechanism involving predominant frontside nucleophilic attack is proposed on the basis of the primary normal DKIEs and selectivity parameters. Hydrogen bonded, four-center-type transition state is proposed. The steric effects of the two ligands on the anilinolysis rates of the chlorothiophosphates are discussed. The anilinolyses of P=S systems are compared with those of their P=O counterparts on the basis of the reactivities, thio effects, selectivity parameters, and DKIEs.

• Bulletin of the Korean Chemical Society
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• v.32 no.9
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• pp.3245-3250
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• 2011

The nucleophilic substitution reactions of diisopropyl chlorophosphate (3) with substituted anilines ($XC_6H_4NH_2$) and deuterated anilines ($XC_6H_4ND_2$) are investigated kinetically in acetonitrile at $55.0^{\circ}C$. The anilinolysis rate of 3 is rather slow to be rationalized by the conventional stereoelectronic effects. The obtained deuterium kinetic isotope effects (DKIEs; $k_H/k_D$) are secondary inverse ($k_H/k_D$ = 0.71-0.95) with maximum magnitude at X = H.A concerted mechanism involving predominant backside nucleophilic attack is proposed on the basis of the secondary inverse DKIEs.

• Bulletin of the Korean Chemical Society
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• v.32 no.12
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• pp.4403-4407
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• 2011

The nucleophilic substitution reactions of dipropyl chlorothiophosphate (3) with substituted anilines ($XC_6H_4NH_2$) and deuterated anilines ($XC_6H_4ND_2$) are investigated kinetically in acetonitrile at $55.0^{\circ}C$. The obtained deuterium kinetic isotope effects (DKIEs; $k_H/k_D$) are primary normal ($k_H/k_D$ = 1.11-1.35). A concerted mechanism involving predominant frontside nucleophilic attack is proposed on the basis of the primary normal DKIEs and selectivity parameters. Hydrogen bonded, four-center-type transition state is proposed. The steric effects of the two ligands on the anilinolysis rates of various substrates are discussed.

• Bulletin of the Korean Chemical Society
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• v.35 no.4
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• pp.1016-1022
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• 2014

The kinetic studies on the reactions of O-methyl N,N-diisopropylamino phosphonochloridothioate with X-anilines and X-pyridines have been carried out in acetonitrile. The free energy relationship with X in the anilines exhibits biphasic concave upwards with a break region between X = (H and 4-F), giving unusual negative ${\beta}_X$ and positive ${\rho}_X$ values with weakly basic anilines. The unusual phenomenon is rationalized by isokinetic relationship. A stepwise mechanism with a rate-limiting leaving group departure from the intermediate is proposed based on the selectivity parameter and variation trend of the deuterium kinetic isotope effects with X. The free energy relationship with X in the pyridines exhibits biphasic concave upwards with a break point at X = 3-MeO. A concerted mechanism is proposed based on relatively small ${\beta}_X$ value, and frontside and backside nucleophilic attack are proposed with strongly and weakly basic pyridines, respectively.

• YAKHAK HOEJI
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• v.39 no.2
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• pp.118-130
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• 1995

Aliphatic & aromatic compounds with two nucleophilic functional groups which were chosen as nucleophiles reacted with 2,3-dichloro-1,4-naphthoquinone as a substrate to give cyclized products by nucleophilic vinyl substitution. And the trends in the syntheses of the heterocyclic compounds was studied and expounded. Besides, the biological activities of the products, especially activity as an agricultural chemical, were examined. Moreover 5-aminomethyl-2-pyrrolidinone was synthesized for the purpose of forming a polynuclear heterocyclic compound containing a similar structure of azasteroid. However only one chlorine of 2,3-dichloro-1,4-naphthoquinone was replaced by an amino group of pyrrolidinone and cyclization did not take place.

• Journal of the Korean Chemical Society
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• v.18 no.4
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• pp.251-258
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• 1974

The rate constants for the nucleophilic substitution reactions of substituted benzoyl chlorides with p-nitroaniline in such solvents as acetone, acetonitrile, methanol, ethanol, etc. were conductometrically determined, and the activation thermodynamic parameters were also evaluated. In result, the reaction rates were faster in protic solvents than in aprotic solvent; in the solvents of similar property, the reaction rate in the solvent of the large dielectric constant was faster than that in the solvent of the small dielectric constant. Hammett plots in individual solvents showed the straight lines with positive slope; and we concluded that the reaction occurred via the addition-elimination mechanism.

• Bulletin of the Korean Chemical Society
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• v.24 no.5
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• pp.583-592
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• 2003

The gas phase identity nucleophilic substitution reactions of halide anions (X = F, Cl, Br) with cyclopentadienyl halides (1) are investigated at the B3LYP/6-311+G**, MP2/6-311+G** and G2(+)MP2 levels involving five reaction pathways: σ-attack $S_N2$, β-$S_N$2'-syn, β-$S_N$2'-anti, γ-$S_N$2'-syn and γ-$S_N$2'-anti paths. In addition, the halide exchange reactions at the saturated analogue, cyclopentyl halides (2), and the monohapto circumambulatory halide rearrangements in 1 are also studied at the same three levels of theory. In the σ-attack $S_N2$ transition state for 1 weak positive charge develops in the ring with X = F while negative charge develops with X = Cl and Br leading to a higher energy barrier with X = F but to lower energy barriers with X = Cl and Br than for the corresponding reactions of 2. The π-attack β-$S_N$2' transition states are stabilized by the strong $n_C-{\pi}^{*}_{C=C}$ charge transfer interactions, whereas the π-attack γ-$S_N$2' transition states are stabilized by the strong $n_C-{\sigma}^{*}_{C-X}$ interactions. For all types of reaction paths, the energy barriers are lower with X = F than Cl and Br due to the greater bond energy gain in the partial C-X bond formation with X = F. The β-$S_N$2' paths are favored over the γ-$S_N$2' paths only with X = F and the reverse holds with X = Cl and Br. The σ-attack $S_N2$ reaction provides the lowest energy barrier with X = Cl and Br, but that with X = F is the highest energy barrier path. Activation energies for the circumambulatory rearrangement processes are much higher (by more than 18 kcal $mol^{-1}$) than those for the corresponding $S_N2$ reaction path. Overall the gas-phase halide exchanges are predicted to proceed by the σ-attack $S_N2$ path with X = Cl and Br but by the β-$S_N$2'-anti path with X = F. The barriers to the gas-phase halide exchanges increase in the order X = F < Br < Cl, which is the same as that found for the gas-phase identity methyl transfer reactions.

• Archives of Pharmacal Research
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• v.12 no.2
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• pp.138-142
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• 1989

The nucleophilic substitution reaction of 6-chloro purines (I) with malononitrile and ethyl cyanoacetate is carried out in DMSO and in the presence of an alkali. The possible tautomeric-ylidene form for the products is considered and discussed in view of IR, UV, NMR and mass spectral determinations. The derivatives were tested for their antitumor activities.

• Bulletin of the Korean Chemical Society
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• v.33 no.2
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• pp.373-374
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• 2012