The Experts below are selected from a list of 264 Experts worldwide ranked by ideXlab platform
M Tashiro - One of the best experts on this subject based on the ideXlab platform.
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a new route for the preparation of 10 11 dihydro 5h dibenzo a d Cycloheptene using friedel crafts intramolecular cyclobenzylation
Synthesis, 1991Co-Authors: Takehiko Yamato, Maki Fukumoto, N Sakaue, Takashi Furusawa, M TashiroAbstract:A convenient preparation of 10,11-dihydro-5H-dibenzo[a,d]Cycloheptene based on a novel Friedel-Crafts intramolecular cyclobenzylation, involving five steps from 1,2-diphenylethane, is described
Walter Weissensteiner - One of the best experts on this subject based on the ideXlab platform.
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Conformational analysis of 5-H-dibenzo[a,d]Cycloheptene derivatives with flexible amino-substituted side-chains by means of lanthanide induced shifts (LIS). Conformational analysis of highly flexible structures, part III
Monatshefte für Chemie Chemical Monthly, 1992Co-Authors: Otmar Hofer, Walter WeissensteinerAbstract:Die LIS -Werte von 5-(3-N,N-Dimethylaminopropyl)-5 H -dibenzo[a,d]-cyclohepten ( 1 ), 5-(3-N,N-Dimethyl- bzw. 5-(3-N-Methylaminopropyliden)-10,11-dihydro-5 H -dibenzo[a,d]-cyclohepten ( 2 bzw. 2a ) und 5-(3-N,N-Dimethylaminopropyl)-10,11-dihydro-5 H -dibenzo[a,d]cyclohepten ( 3 ) wurden zur Berechnung von Populationen bevorzugter Konformerer herangezogen. Die Geometrien der einzelnen Konformeren wurden aus Force-Field-Rechnungen entnommen. Es wurde ein LIS -Programm verwendet, das bei der Simulation bis zu vier Konformationen berücksichtigen kann. Die Grenzen der Anwendbarkeit der Methode — insbesondere die speziellen Probleme die auftreten, wenn die Koordinationsstelle innerhalb einer flexiblen Kette liegt — werden diskutiert. The LIS data of 5-(3-N,N-dimethylaminopropyl)-5 H -dibenzo[a,d]Cycloheptene ( 1 ), 5-(3-N,N-dimethyl-and 5-(3-N-methylaminopropylidene)-10,11-dihydro-5 H -dibenzo[a,d]-Cycloheptene ( 2,2a ) and 5-(3-N,N-dimethylaminopropyl)-10,11-dihydro-5 H -dibenzo[a,d]Cycloheptene ( 3 ) were used to calculate populations of possible conformers in solution. The substrate geometries of the particular conformers were taken from force field calculations. A LIS simulation program was used which is able to handle up to four possible conformations. The limits and special features of the method for highly flexible structures — especially for the case that the coordinating group is within a flexible chain — are discussed.
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conformational analysis of 5 h dibenzo a d Cycloheptene derivatives with flexible amino substituted side chains by means of lanthanide induced shifts lis conformational analysis of highly flexible structures part iii
Monatshefte Fur Chemie, 1992Co-Authors: Otmar Hofer, Walter WeissensteinerAbstract:TheLIS data of 5-(3-N,N-dimethylaminopropyl)-5H-dibenzo[a,d]Cycloheptene (1), 5-(3-N,N-dimethyl-and 5-(3-N-methylaminopropylidene)-10,11-dihydro-5H-dibenzo[a,d]-Cycloheptene (2,2a) and 5-(3-N,N-dimethylaminopropyl)-10,11-dihydro-5H-dibenzo[a,d]Cycloheptene (3) were used to calculate populations of possible conformers in solution. The substrate geometries of the particular conformers were taken from force field calculations. ALIS simulation program was used which is able to handle up to four possible conformations. The limits and special features of the method for highly flexible structures — especially for the case that the coordinating group is within a flexible chain — are discussed.
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Conformation and internal mobility of 5H-dibenzo[a,d]Cycloheptene derivatives in solution. Conformational analysis of highly flexible structures, part II
Monatshefte für Chemie Chemical Monthly, 1992Co-Authors: Walter WeissensteinerAbstract:The conformational possibilities of 5-(3′-N,N-dimethylaminopropyl)-5 H -dibenzo[a,d]Cycloheptene ( 1 ), 5-(3′-N,N-dimethylaminopropylidene)-10,11-dihydro-5 H -dibenzo[a,d]Cycloheptene ( 2 ), and 5-(3′-N,N-dimethylaminopropyl)-10,11-dihydro-5 H -dibenzo[a,d]Cycloheptene ( 3 ) are analysed using empirical force field methods. Minimum energy conformations, interconversion pathways, interconversion graphs and interconversion energies are examined in view of the analysis of conformer equilibria of 1 , 2 , or 3 in solution. In addition, some basic requirements of the analysis of fast interconverting conformers using the lanthanide induced shift method are discussed. Die konformativen Möglichkeiten von 5-(3′-N,N-dimethylaminopropyl)-5 H -dibenzo[a,d]cyclohepten ( 1 ), 5-(3′-N,N-dimethylaminopropylidene)-10,11-dihydro-5 H -dibenzo[a,d]cyclohepten ( 2 ) und 5-(3′-N,N-dimethylaminopropyl)-10,11-dihydro-5 H -dibenzo[a,d]cyclohepten ( 3 ) wurden mit Hilfe empirischer Kraftfeldmethoden analysiert. Jene Konformationen, die einem energetischen Minimum entsprechen, sowie Interkonversionswege, Interkonversionsgraphen und Interkonversionsenergien wurden in Hinblick auf die Analyse der Konformerengleichgewichte von 1 , 2 oder 3 in Lösung untersucht. Weiters werden noch einige grundlegende Voraussetzungen für die Analyse von sich schnell ineinander umwandelnden Konformeren mittels der Lanthaniden-induzierten Verschiebungsmethode besprochen.
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conformation and internal mobility of 5h dibenzo a d Cycloheptene derivatives in solution conformational analysis of highly flexible structures part ii
Monatshefte Fur Chemie, 1992Co-Authors: Walter WeissensteinerAbstract:The conformational possibilities of 5-(3′-N,N-dimethylaminopropyl)-5H-dibenzo[a,d]Cycloheptene (1), 5-(3′-N,N-dimethylaminopropylidene)-10,11-dihydro-5H-dibenzo[a,d]Cycloheptene (2), and 5-(3′-N,N-dimethylaminopropyl)-10,11-dihydro-5H-dibenzo[a,d]Cycloheptene (3) are analysed using empirical force field methods. Minimum energy conformations, interconversion pathways, interconversion graphs and interconversion energies are examined in view of the analysis of conformer equilibria of1,2, or3 in solution. In addition, some basic requirements of the analysis of fast interconverting conformers using the lanthanide induced shift method are discussed.
Takehiko Yamato - One of the best experts on this subject based on the ideXlab platform.
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a new route for the preparation of 10 11 dihydro 5h dibenzo a d Cycloheptene using friedel crafts intramolecular cyclobenzylation
Synthesis, 1991Co-Authors: Takehiko Yamato, Maki Fukumoto, N Sakaue, Takashi Furusawa, M TashiroAbstract:A convenient preparation of 10,11-dihydro-5H-dibenzo[a,d]Cycloheptene based on a novel Friedel-Crafts intramolecular cyclobenzylation, involving five steps from 1,2-diphenylethane, is described
Danamihaela Cioroianu - One of the best experts on this subject based on the ideXlab platform.
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synthesis of new 10 11 dihydrodibenzo a d Cycloheptene s thiocarbamate derivatives via a benzylic newman kwart rearrangement
Tetrahedron Letters, 2014Co-Authors: Miron Teodor Căproiu, Florea Dumitrascu, Sergiu Shova, Ileana Cornelia Chirită, Alexandru Vasile Missir, Danamihaela CioroianuAbstract:New S-thiocarbamates possessing a 10,11-dihydro-5H-dibenzo[a,d]Cycloheptene moiety were obtained unexpectedly in the process of preparing new O-thiocarbamates starting from 5-dibenzosuberol (10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5-ol) and aroyl-isothiocyanates. These compounds were obtained via a benzylic Newman–Kwart rearrangement mechanism. The structures of the new thiocarbamates were confirmed by elemental analysis, IR, and NMR spectroscopy and by X-ray crystallography.
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Synthesis of new 10,11-dihydrodibenzo[a,d]Cycloheptene S-thiocarbamate derivatives via a benzylic Newman–Kwart rearrangement
Tetrahedron Letters, 2014Co-Authors: Miron Teodor Căproiu, Florea Dumitrascu, Sergiu Shova, Ileana Cornelia Chirită, Alexandru Vasile Missir, Danamihaela CioroianuAbstract:New S-thiocarbamates possessing a 10,11-dihydro-5H-dibenzo[a,d]Cycloheptene moiety were obtained unexpectedly in the process of preparing new O-thiocarbamates starting from 5-dibenzosuberol (10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5-ol) and aroyl-isothiocyanates. These compounds were obtained via a benzylic Newman–Kwart rearrangement mechanism. The structures of the new thiocarbamates were confirmed by elemental analysis, IR, and NMR spectroscopy and by X-ray crystallography.
James Defellipis - One of the best experts on this subject based on the ideXlab platform.
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how stable is trans Cycloheptene
Journal of the American Chemical Society, 2005Co-Authors: Michael E Squillacote, James DefellipisAbstract:There is a discrepancy between the observed and calculated stability of trans-Cycloheptene (t-CHP). Generation of t-CHP has always led to its low-temperature (−40 °C) isomerization to cis-Cycloheptene (c-CHP). However, force field and semiempirical calculations on the energy difference between the two isomers have suggested that t-CHP should be stable at room temperature. We performed a series of ab initio calculations, which predicted that the simple process of double bond rotation leading from t-CHP to c-CHP would have an activation barrier too high to permit isomerization below 100 °C (35 kcal/mol). The validity of our calculation method on this very strained system was supported by the agreement between the calculation and the dynamics of the ring flip of the unsymmetrical t-CHP ring and the observed NMR shifts and coupling constants for the system. This incompatibility between the experimental behavior of t-CHP and our calculations led to our reexamining the decay kinetics of t-CHP. We find that this...
