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편상용,백규철,한만소,조봉래 대한화학회 2016 Bulletin of the Korean Chemical Society Vol.37 No.3
Nucleophilic substitution reactions of 5‐XC4H2 (S)C(O)OC6H3 ‐2‐Y‐4‐NO2 (1) promoted by 4‐Z‐C6H4O −/4‐Z‐C6H4OH in 20 mol % dimethyl sulfoxide (DMSO)(aq) have been studied kinetically. The reactions exhibited second‐order kinetics with βacyl = −2.52 to −2.83, ρ(x) = 2.81–3.16, βnuc = 0.88–0.04 and βlg = −0.94, respectively. The results have been interpreted with an addition–elimination mechanism in which the nucleophilic attack occurs in the rate‐determining step. Comparison with existing data reveals that the rate‐determining step changes from the second to the first step by the change in the nucleophile from R2NH/R2NH2 + to 4‐Z‐C6H4O −/4‐Z‐C6H4OH.
편상용,백규철,한만소,조봉래 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.12
Nucleophilic substitution reactions of 5-XC4H2(S)C(O)OC6H3 -2-Y-4-NO2 (1) promoted by 4-Z-C6H4O −/4-Z-C6H4OH in 20 mol % dimethyl sulfoxide (DMSO)(aq) have been studied kinetically. The reactions exhibited second-order kinetics with βacyl = −2.52 to −2.83, ρ(x) = 2.81–3.16, βnuc = 0.88–0.04 and βlg = −0.94, respectively. The results have been interpreted with an addition–elimination mechanism in which the nucleophilic attack occurs in the rate-determining step. Comparison with existing data reveals that the rate-determining step changes from the second to the first step by the change in the nucleophile from R2NH/R2NH2 + to 4-Z-C6H4O −/4-Z-C6H4OH.
편상용,백규철,한만소,홍승택,조봉래 대한화학회 2023 Bulletin of the Korean Chemical Society Vol.44 No.11
The kinetics of nucleophilic substitution reactions involving 2,4-dinitrophenyl 5-substituted-2-thiophenecarboxylate were studied kinetically with 4-Z-C6H4O−/4-Z-C6H4OH, which facilitated the reactions, in 20 mol% DMSO(aq). The reactions followed second-order kinetics and exhibited βacyl = −2.34 to −2.92, ρ(Y) = 2.71–3.39, βnuc = 0.74–0.83, and |βlg| = 0.40–0.57. Based on the interpretation of the results, we have concluded that the reaction follows an addition–elimination mechanism in which the first step is the rate-determining step (rds). The transition state structures for the 4-ZC6H4O−-promoted reactions remained nearly the same with a change in the leaving group from 4-nitrophenoxide to 2,4-dinitrophenoxide. The mechanism of the 4-ZC6H4O−-promoted reaction was similar to that of R2NH-promoted reactions, except that the former proceeded with the 1st step being the rds and the latter proceeded with a change in the rds from the second to the first step with a stronger nucleophile.
김태린,정동인,편상용,Kim, Tae Rin,Chung, Dong In,Pyun, Sang Yong 대한화학회 1996 대한화학회지 Vol.40 No.8
A simple and efficient new synthetic method of 4'-[N-(9-acridinyl)]-1'-(N-methanesulfonyl)-3'-methoxyquinonediimide(AMQD, 5) was developed and six new nucleophilic adducts(6a-6f) were prepared by the addition of thiophenol derivatives to AMQD. The structures of these compounds were confirmed by elemental analysis, mass, ir and nmr spectra. 4'-[N-(9-acridinyl)]-1'-(N-methanesulfonyl)-3'-methoxyquinonediimide(AMQD, 5)를 간편하고 효율적인 새로운 방법으로 얻었으며, AMQD에 thiophenol 유도체를 반응시켜 6종류의 새로운 첨가 생성물(6a-6f)들을 합성하였다. 이 화합물들의 구조는 원소분석, Mass, IR 및 NMR 스펙트라 등에 의하여 확인되었다.
S-Phenyl-S-vinyl-N-p-tosylsulfilimine 유도체에 대한 Thioglycolic Acid의 친핵성 첨가반응에 관한 반응속도론적 연구
김태린,한만소,편상용,Kim, Tae Rin,Han, Man So,Pyun, Sang Yong 대한화학회 1996 대한화학회지 Vol.40 No.10
Vinylsulfilimine(VSI) 유도체($p-OCH_3$, H, p-Cl 및 p-Br)에 대한 thioglycolic acid의 친핵성 첨가반응속도를 자외선 분광법으로 측정하여 넓은 pH 범위에서 적용될 수 있는 속도식을 구하였다. pH에 따른 속도상수의 변화, general base 및 치환기 효과 등을 바탕으로 반응 메카니즘을 제안하였다. 즉 pH3.0 이하에서는 sulfilimine의 질소에 양성자가 먼저 첨가된 다음 중성 thioglycolic acid 분자가 탄소 이중결합에 첨가되고, pH 3.0-9.0 영역에서 thioglycolic acid의 중성분자와 음이온의 첨가가 경쟁적으로 일어나며, pH 9.0 이상에서는 황화 음이온이 첨가되는 전형적인 Michael type의 반응이 진행됨을 알았다. The rate constants for the nucleophilic addition reactions of thioglycolic acid to vinylsulfilimine(VSI) derivatives(p-OCH3, H, p-Cl and p-Br) were determined by an ultraviolet spectrophotometric method, and rate equations which can be applied over a wide pH range were obtained. On the basis of rate equation, general base catalysis and substituent effect, a plausible addition reaction mechanism was proposed: Below pH 3.0, the reaction was proceeded via the addition of neutral molecule to carbon-carbon double bond after protonation at the nitrogen atom of the sulfilimine, and in the pH range of 3.0 to 9.0, the neutral molecule and its anion attacked to carbon-carbon double bond competitively. Above pH 9.0, sulfide anion added to the double bond (Michael type addition).
Styryldiphenylphosphine Oxide의 가수분해 반응 메카니즘에 관한 반응속도론적 연구
김태린,신갑철,편상용,이석희,Kim, Tae Rin,Shin, Gap Cheol,Pyun, Sang Yong,Lee, Seok Hee 대한화학회 2000 대한화학회지 Vol.44 No.5
Styryldiphenylphosphine(SDPO)의 가수분해 속도상수를 자외선 분광법으로 측정하여 넓은 pH에서 잘 맞는 반응속도식을 구하였다. pH에 따르는 속도상수의 변화, 가수분해 생성물의 확인, 일반염기 및 치환기 효과 등으로부터 실험 결과에 잘 맞는 반응 메커니즘을 제안하였다. 즉 pH 4.5 이하에서는 phosphine oxide기의 산소에 양성자가 첨가된 다음 탄소 이중결합에 물의 첨가가 일어나 가수분해가 진행되며, pH 4.5-8.0 사이에서는 물분자와 수산와 음이온의 첨가가 경쟁적으로 일어나 반응이 진행되었고, pH 8.0 이상에서는 반응속도 상수가 수산화 음이온의 농도에만 비례함을 알았다. The rate constants for the hydrolysis of styryldiphossphine oxide(SDPO) were deter-mined by ultraviolet visible spectrophotometric method and rate equation which can be applied over wide pH ranges was obtained. On the basis of pH-rate profile, hydrolysis product analysis, general base catalysis and substituent effect, a plausible hydrolysis mechanism is proposed : Below pH 4.5, the hydrolysis reaction is pro-ceeded by the attack of water to carbocation after protonaticentration of hydroxide ion.