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5. Reactions of 2,4‐dinitrophenyl 5‐substituted‐2‐thiophenecarboxylate promoted by 4‐ZC6H4O−/4‐ZC6H4OH in 20 mol% DMSO(aq). Effects of leaving group and nucleophile on the acyl transfer reactions

Author

Pyun, Sang Yong, Paik, Kyu Cheol, Han, Man So, Hong, Seung Taek, and Cho, Bong Rae

Subjects
ACYL group, NUCLEOPHILIC substitution reactions, DIMETHYL sulfoxide, SUBSTITUTION reactions
Abstract

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. [ABSTRACT FROM AUTHOR]

Published
2023
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6. Reactions of 2,4‐dinitrophenyl 5‐substituted‐2‐thiophenecarboxylate promoted by 4‐ZC6H4O−/4‐ZC6H4OHin 20 mol% DMSO(aq). Effects of leaving group and nucleophile on the acyl transfer reactions

Author

Pyun, Sang Yong, Paik, Kyu Cheol, Han, Man So, Hong, Seung Taek, and Cho, Bong Rae

Abstract

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.

Published
2023
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10. Two-Photon Probe for TNF-α. Assessment of the Transmembrane TNF-α Level in Human Colon Tissue by Two-Photon Microscopy

Author

Hong, Seung Taek, primary, Koh, Byumseok, additional, Choi, Seong Ji, additional, Yoon, Eunyoung, additional, Pyo, Min Cheol, additional, Choi, Ji-Woo, additional, Kim, Mun Seok, additional, Lee, Eun Jeong, additional, Paik, Kyu Cheol, additional, Han, Man So, additional, Chun, Hoon Jai, additional, Heo, Jung-Nyoung, additional, Kim, Eun Sun, additional, and Cho, Bong Rae, additional

Published
2019
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13. Two-photon probes for pH: Detection of human colon cancer using two-photon microscopy.

Author

Kim, Woojung, primary, Kim, Eun Sun, additional, Min, Geeho, additional, Kim, Seung Han, additional, Choi, Seong ji, additional, Lee, Jung Min, additional, Lee, Jae Min, additional, Choi, Hyuk Soon, additional, Keum, Bora, additional, Jeen, Yoon Tae, additional, Lee, Hong Sik, additional, Chun, Hoon Jai, additional, Kim, Chang Duck, additional, Hong, Seung Taek, additional, Heo, Jung-Nyoung, additional, and Cho, Bong Rae, additional

Published
2018
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