Exceptional Products of the Desulfurization ofN,2-Diaryl-5-(arylimino)- 2,5-dihydro-4-nitroisothiazol-3-amines

Argilagos, Dally Moya; Linden, Anthony; Heimgartner, Heinz

doi:10.1002/(sici)1522-2675(19990210)82:2<238::aid-hlca238>3.0.co;2-h

Cited by 5 publications

(3 citation statements)

References 21 publications

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“…After Michael addition, five different paths (1−5) have been proposed here and modeled by using density functional theory. The potential energy surfaces give rise to very interesting intermediate species 17 and 28 , which have also been proposed for several other reactions. ,, The following conclusions can be drawn from this study:…”

Section: Discussionsupporting

confidence: 67%

“…TS8 is the transition state for water elimination, in which the σ bonds N1−H13 and N4−O18 break while the N1−N4 and H13−O18 bonds form to give a four-membered cyclic intermediate 17 , namely, 1,4-dihydro-1,2-diazete or a diazacyclobutene derivative. A similar type of intermediate, 17 , was also proposed as the intermediate in the formation mechanism of 1,2,5-oxadiazole derivatives by desulfurization of substituted 2-aryl-3-phenylamino-4-nitro-5-aryliminoisothiaozole derivatives . (Scheme ).…”

Section: Resultsmentioning

confidence: 95%

“…One important feature of this annulation reaction is the synthesis of a new quinoxalinone- N -oxide derivative ( 9 ). Quinoxalinone- N -oxide derivatives reported in the literature − so far are given in Scheme . Additionally, the ability of substitution of the Cl atom at the 3-position allows one to derive new quinoxalinone- N -oxides easily.…”

Section: Introductionmentioning

confidence: 99%

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A DFT Study on the Mechanism of the Annulation Reaction of Trichloronitroethylene with Aniline in the Synthesis of Quinoxalinone-N-oxides

et al. 2009

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The new annulation reaction of trichloronitroethylene with aniline results in the formation of a quinoxalinone-N-oxide derivative. The mechanism of this one-pot annulation reaction between trichloronitroethylene (TCNiE) and anilines has been extensively investigated with B3LYP/6-31+G** methodology. Five different paths (1-5) were proposed and modeled by using this method. These paths were compared in terms of the activation energies of their rate-determining steps and in regard to the experimental findings. Paths 3 and 5, proceeding via four-membered heterocyclic rings, were found to be the most plausible paths with activation energies of 32 and 29 kcal/mol for the rate-determining steps, respectively. The effects of substituent, solvent, temperature, and computational method on these steps were also investigated. The results showed that path 5 is the most plausible mechanism for the annulation reaction of trichloronitroethylene with aniline.

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Section: Discussionsupporting

confidence: 67%

Section: Resultsmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

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A DFT Study on the Mechanism of the Annulation Reaction of Trichloronitroethylene with Aniline in the Synthesis of Quinoxalinone-N-oxides

et al. 2009

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Theoretical Study of the [2+3] Cycloaddition of Nitrones to Nitriles—Influence of Nitrile Substituent, Solvent and Lewis Acid Coordination

Wagner

2003

Chemistry A European J

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The [2+3] cycloaddition of nitrone PhCHdoublebondN(Me)O to nitriles RCtriplebondN (R=Me, Ph, CF(3)) was studied using quantum chemical calculations at the HF/6-31G* and B3LYP/6-31G* level of theory. With MeCN and PhCN, the reaction occurs through a concerted mechanism and leads selectively to Delta(4)-1,2,4-oxadiazolines rather than Delta(2)-1,2,5-oxadiazolines. Electron withdrawing substituents such as CF(3) at the nitrile provoke a non-synchronous bond formation, with the C-O bond being established on an earlier stage than the C-N bond. Additionally, the reaction becomes thermodynamically and kinetically more favourable. In the reaction of adducts of MeCN with BH(3) or BF(3) as model Lewis acids, the mechanism was found to change from fully concerted in the case of free MeCN towards a two-step reaction in the presence of BF(3), in which C-O bond formation occurs first. The BH(3)-mediated reaction occupies an intermediate stage where ring formation occurs in one-step but non-simultaneously, similar to the reaction of CF(3)CN. Interaction of the Lewis acid with the nitrile in the course of the reaction facilitates the cycloaddition by stabilizing transition states, intermediate and product rather than by activating the nitrile. The solvent influences the organic reaction mainly by lowering the energy of the reagents, thus leading to a higher activation barrier in a more polar solvent. In the Lewis acid mediated reaction, in contrast, the intermediate is strongly stabilised by a polar solvent and with that the synchronicity of the reaction changes in favour of a two-step mechanism.

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Isothiazoles

Clerici

Gelmi

Pellegrino

2008

Comprehensive Heterocyclic Chemistry III

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Exceptional Products of the Desulfurization ofN,2-Diaryl-5-(arylimino)- 2,5-dihydro-4-nitroisothiazol-3-amines

Cited by 5 publications

References 21 publications

A DFT Study on the Mechanism of the Annulation Reaction of Trichloronitroethylene with Aniline in the Synthesis of Quinoxalinone-N-oxides

A DFT Study on the Mechanism of the Annulation Reaction of Trichloronitroethylene with Aniline in the Synthesis of Quinoxalinone-N-oxides

Theoretical Study of the [2+3] Cycloaddition of Nitrones to Nitriles—Influence of Nitrile Substituent, Solvent and Lewis Acid Coordination

Isothiazoles

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