• Title/Summary/Keyword: Aziridine Ring

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Substituents Effect on Aziridine Chemistry: N-Inversion Energy, Reactivity and Regioselectivity of Nucleophilic Ring-opening

  • Park, Gyoo-Soon;Kim, Seok-Chan;Kang, Han-Young
    • Bulletin of the Korean Chemical Society
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    • v.26 no.9
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    • pp.1339-1343
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    • 2005
  • The N-inversion energies and nucleophilic ring-opening reactions of N-substituted aziridine compounds are investigated using B3LYP/6-31+$G^*$ methods, where substituents (R) on the nitrogen atom has been H (1), Me (2), Ph (3), Bn (4), CHMePh (5), $CO_2Me$ (6), COPh (7) and $SO_2Ph$ (8). The N-inversion energy with X group are decreased as the following order: R = CHMePh (17.06 kcal/mol) $\gt$ Me (16.97) $\gt$ Bn (16.70) $\gt$ H (16.64) $\gt$ $SO_2Ph$ (12.18) $\gt$ Ph (8.91) $\gt$ COPh (5.75) $\gt$ $CO_2Me$ (5.48). For reactivity of the ring opening toward cyanide ion, the aziridine 6 (R=$CO_2Me$) is shown to be the most reactive one. During the ring opening of aziridine 6 by CN$^{\ominus}$, the torsional OCNC angle becomes near to $180^{\circ}$, where the geometry allows for the effective incorporation of electrons of the nitrogen atom to the C=O bond. It would be a possible driving force for nucleophilic ring opening reaction as well as decreasing the N-inversion energy barrier. Regarding to the regioselectivity, the orientation of nucleophile in ring opening reaction appears to be different in the case of 9 and 10. The results are discussed in terms of steric/electronic effect of the $C_2$-substituents.

Semiempirical MO Calculation of Hetero Atom Three-Membered Ring Compounds (I) : N-Nitroso-aziridine, -oxaziridine, and -dioxaziridine

  • Hwang, Ki-Woon
    • Bulletin of the Korean Chemical Society
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    • v.11 no.5
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    • pp.422-426
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    • 1990
  • Fully optimized MNDO molecular orbital calculations are described for N-nitroso-aziridine (I), -oxaziridine (II), and -dioxaziridine (III). The ground state geometries show the nonplanar configuration around the imino nitrogen. The nitroso group rotational energy barriers are 3.25, 0.43 and 1.18 kcal/mol for I, II and III, respectively. Also the calculated aziridine ring inversion barriers are 3.98, 15.61 and 27.46 kcal/mol for I, II and III, respectively.

Bicyclic Derivatives of Aziridine - Materials for New Indicators of Radiation

  • Chebanov, V.A.;Zbruyev, A.I.;Desenko, S.M.;Doroshenko, A.O.;Vaschenko, V.V.
    • Journal of Radiation Protection and Research
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    • v.30 no.1
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    • pp.31-34
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    • 2005
  • The article is devoted to the study of some hi-and tricyclic derivatives of aziridine as materials lot newindicators of ionizing radiation. To create high sensitive materials some aspects of photo induced ring opening processes in aziridine derivatives in ethanol solutions and in polymeric matrix were studied and two steps character of the processes investigated was established. Two types of radioindicators were suggested and preliminary tested. The new way of synthesis of radiochromic derivatives of aziridine was developed and series of target compounds synthesized.

Silyl-Tranfer Photoreactions of Trimethylsilylmethyl Substituted Acyclic N-Sulfonylbenzamides

  • Oh, Sun-Wha
    • Journal of Photoscience
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    • v.12 no.2
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    • pp.63-66
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    • 2005
  • The azomethine ylide forming photoreaction has been explored by probing the excited state chemistry of several N-trimethylsilylmethyl substituted cyclic and acyclic imides and amide analogs. N-[(Trimethylsilyl)methyl]-N-mesylbenzamide (5) undergoes the excited state C to O silyl migration reaction to produce azomethine ylide intermediate 13. This ylide undergoes electrocyclization to form transient aziridine intermediate 14 which react further by ring opening to generate N-phenacylamine product 10. On the other hand, photolysis of N-[N-mesyl-N-(trimethylsilyl)methyl]aminoethyl-N-mesylbenzamide (8) brings about desilylation resulting in the production of dimer 17.

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Studies on the Oxidative Rearrangement of Aziridine N-Oxides (아지리딘 N-옥시드의 酸性化 자리옮김 反應에 關한 硏究)

  • Se Chun Choi;Hyang Dong Jang
    • Journal of the Korean Chemical Society
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    • v.27 no.1
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    • pp.38-45
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    • 1983
  • Aziridine derivatives were utilized for the formation of aziridine N-oxides at low temperature, which were subject to easy decomposition and/or rearrangement like the protonated aziridines at room temperature. t-Butyl nitroso compound formed by the decomposition of N-oxide is easily characterized by its blue color and it is the major product in case that no branched alkyl groups are substituted on the carbon atoms of the aziridine ring and the stationary groups on the nitrogen are inert to rearrange the oxide such as the t-butyl group. The oxidative rearrangement products, however, are mainly formed when the substituents are methyl or ethyl group on the carbon atoms. It is interesting to see that the sigmatropic rearrangement of 2-ethyl aziridine gave only cis olefinic compound selectively in case that t-butyl group was substituted on the nitrogen, whereas N-hydroxy aziridine compounds were formed exclusively when t-butyl group was replaced with ethyl group.

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Ring-Opening Reaction of 2,2-gem-Diphenylaziridine (2,2-gem-Diphenylaziridine의 開環反應)

  • Hahn, Chi-Sun;Nam-Goong, Ha-Il;Kang, Yong-Ik
    • Journal of the Korean Chemical Society
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    • v.13 no.3
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    • pp.229-232
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    • 1969
  • A study of the ring-opening reaction of 2,2-gem-diphenylaziridine by treating with acetic acid has been undertaken. The structure of the ring-opened product was confirmed as 1,1-diphenyl-2-aminoethyl acetate. It is most likely that the reaction proceeds through the cleavage of a bond between nitrogen and tertiary carbon atoms in the aziridine ring, followed by the formation of a carbonium ion intermediate.

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