Near u.v. absorption spectra of unconjucated bisimines of tetramethyl-1,3-cyclobutanedione

Worman, James J.; Schmidt, Edward A.; Olson, Edwin S.; Jensen, William P.; Schultz, Ronald D.

doi:10.1016/0584-8539(76)80192-4

Cited by 5 publications

(2 citation statements)

References 13 publications

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“…Infrared spectra (KBr, 4000-400 cm -1 ) were recorded on AVATAR-300 Fourier transform spectrophotometer. The Bruker AV400 NMR spectrometer was used for recording NMR spectra operating 400 MHz for 1 H and 100 MHz for 13 C spectra in CDCl 3 solvent using TMS as internal standard. Mass spectra of diimines were recorded on SHIMADZU spectrometer using chemical ionization technique.…”

Section: Generalmentioning

confidence: 99%

“…Diimines possess important biological activities such as antioxidant [9], antiinflammatory and anti-analgesics [10]. Spectroscopic data were used for prediction of ground state molecular equilibration of organic compounds such as, ketones, chalcones [11], imines [12], diimines [13], acyl chlorides [14], bromides and their esters [15]. Recently, Suresh et al,[12] have studied the effects of substituent on infrared C=N, nuclear magnetic resonance chemical shifts (ppm) δCH and CN.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis, IR and NMR spectral correlations in some symmetrical diimines

Thirunarayanan¹

2014

Bull. Chem. Soc. Eth.

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ABSTRACT. A series of diimines have been synthesized by coupling of diamine with substituted benzaldehydes. The purities of these diimines were checked by their analytical and spectroscopic data. The spectral frequencies νCN (cm -1 ), NMR chemical shifts (δ, ppm) of C-H and C=N of these diimines have been correlated with Hammett substituent constants, F and R parameters using single and multi-linear regression analysis. From the results of statistical analysis, the effect of substituents on the above spectral data has been studied.

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Section: Generalmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synthesis, IR and NMR spectral correlations in some symmetrical diimines

Thirunarayanan¹

2014

Bull. Chem. Soc. Eth.

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Proximitätseffekte in der Organischen Chemie — Die photoelektronenspektroskopische Untersuchung nichtbindender und transanularer Wechselwirkungen

Martin

Mayer

1983

Angewandte Chemie

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Klassische Strukturformeln vermitteln hiiufig die Vorstellung, einzig und a h i n jene Beziehungen zwischen den Atomen seien von Bedeutung, welche fur den Zusammenhalt des Molekiils sorgen und durch Bindungsstriche wiedergegeben werden. Viele Wechselwirkungen zwischen Atomen oder Atomgruppen werden jedoch durch diese Schreibweise nicht erfaBt. Ihre Anwesenheit hat dennoch mitunter wichtige Konsequenzen fiir Grundzustandsenergien (cis-Difluorethylen ist stabiler als trans-Difluorethylen), Konformationen (syn-Methylvinylether ist stabiler als die anti-Form), Reaktiuituten (ein endo-standiger Cyclopropanring in 7anti-Norbornylderivaten beschleunigt die Solvolyse um den Faktor IOl4), UV-Spektren (die n-Systeme von Acridin und Purindurch eine viergliedrige Kette verbundenergeben beim ,,Ubereinanderlegen" Hypochromie), CD-Spektren (der inhiirent symmetrische, dissymmetrisch gestarte Chromophor von 2-Deuterionorbornadien IiiBt drei Ubergiinge im nahen UV erkennen) und ESR-Spektren (die Fernkopplung mit H-4 im Briickenkopf-Radikal Bicyclo[2.l.l]hex-l-yl betriigt 22.5 G). An den meisten intramolekularen Effekten dieser Art sind Orbitalwechselwirkungen beteiligt ; die Photoefektronenspektroskopie hat sich wie erwartet als aussagekraftige und wertvolle Erganzung der anderen Methoden erwiesen.

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Retention of Configuration in Two Photochemical Reactions: Formation of Cyclopropanimines by Extrusion of Molecular Nitrogen from Tetraalkyl‐4‐imino‐1‐pyrazolines and [2 + 1] Cycloreversion of Cyclopropanimines to Isocyanides and Alkenes

et al. 1991

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The 1-pyrazolin-4-ones 7 and 9 and the pyrazolidin-4-one 13 are condensed with alkanamines 8 to produce the imines 3, lO and 12 in high yields. Direct irradiation of 3 with 350-nm light at 90°C in deuterated hydrocarbon solvents affords the cyclopropanimines 4 in almost quantitative yields besides molecular nitrogen and small amounts of the imines 12 as a result of photoreduction. In [D,]acetone, the cyclopropanimine 4 b isomerizes in part of the a$-unsaturated imine 14. Direct irradiation of 3 with the unfiltered light of the high-pressure mercury lamp results in quantitative [2 + 1] cycloreversion of the primary photoproducts 4 into the alkene 6 and an isocyanide 5. At low temperature (lO°C), photolysis of 3 occurs much more slowly giving rise to photoextrusion of nitrogen (-4) and photoreduction (-12) to about the same extent. -Photolysis of the stereochemically labelled iminopyrazolines cis-and trans-10 (d.e. 99%) at 90°C produces the cyclopropanimines cis-and trans-16 (d. e. 94%) with high stereospecificity. The configuration of cis-and trans-16 is established by a comparison with the corresponding methylenecyclopropanes cis-and trans-19 and the quantitative and completely stereospecific [2 + 1 1 cycloreversion into methyl isocyanide (5a) and the 3,4-dimethyl-3-hexenes (4-and (4-17 on irradiation with the unfiltered light of the mercury arc. The necessity of thermal activation for efficient nitrogen extrusion from the '(n,n*) state of 3 and 10 is indicative of a considerable energy barrier towards the transition into a dissociative state. At low temperature, hydrogen abstraction from the solvent or other molecules becomes important for the deactivation of the '(n,x*) state, in addition to decay and fluorescence. The stereospecific formation of cis-and trans-16 is interpreted in terms of diastereomeric bis-orthogonal azatrimethylenemethane diradicals as intermediates which retain the configuration on cyclization. The minor non-stereospecific path may involve mono-orthogonal azatrimethylenemethane diradicals. Thus, mechanisms that involve the same types of diradical intermediates can rationalize the photolysis of the iminopyrazolines 3, 10 and of the methylenetriazoline 1 as well. The [2 + 1 1 cycloreversion of cis-and trans-16 into the alkenes (2) and (E)-17 and methyl isocyanide (5a) demonstrates for the first time that such photoreactions can be entirely stereospecific.The chemistry of cyclopropanones 3, has been enriched and extented by the syntheses4-') and reactions8) of cyclopropanimines. A Favorskii-type 1,3-dehydrobromination of cl-bromo ketimines is the method of choice for the synthesis of cyclopropanimines provided that, by virtue of a shielding substitution pattern, they are not too reactive towards nucleophile~~"). On the other hand, highly reactive cyclopropanimines, devoid of ring substituents, are readily available by thermal isomerization of methylena~iridines~~). Eventually, the parent compound has been generated by heterogeneous 1,2-dehydrochlorination of N-chlorocyclopropanamine and iden...

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Near u.v. absorption spectra of unconjucated bisimines of tetramethyl-1,3-cyclobutanedione

Cited by 5 publications

References 13 publications

Synthesis, IR and NMR spectral correlations in some symmetrical diimines

Synthesis, IR and NMR spectral correlations in some symmetrical diimines

Proximitätseffekte in der Organischen Chemie — Die photoelektronenspektroskopische Untersuchung nichtbindender und transanularer Wechselwirkungen

Retention of Configuration in Two Photochemical Reactions: Formation of Cyclopropanimines by Extrusion of Molecular Nitrogen from Tetraalkyl‐4‐imino‐1‐pyrazolines and [2 + 1] Cycloreversion of Cyclopropanimines to Isocyanides and Alkenes

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