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11.
Synthesis and Absolute Configuration of Clemastine and its Isomers. Condensation of 4-chloro-α-methylbenzhydrylalkohol ( 1 ) with 2-(2-chloroethyl)-1-methylpyrrolidine ( 2 ) gave an isomeric mixture of 2-[2-(p-chloro-α-methyl-=-phenylbenzyloxy)ethyl]-1-methylpyrrolidine ( 3 ) and 4-(p-chloro-=-phenylbenzyloxy)-1-methyl-hexahydroazepin ( 4 ). The separation of the four possible optically active isomers of 3 is described and their absolute configuration established by degradation to (R)- and (S)-1-methyl-2-pyrrolidineethanol ( 6 ), respectively, and by an X-ray cristallographic analysis of the quarternary methiodide of the isomer 3-A . Clemastine (3-A) is (+)-(2R)-2-[2-((αR)-(p-chloro-α-methyl-α-phenylbenzyloxy)ethyl)]-1-methylpyrrolidine. 相似文献
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Hans-Peter Abicht Peter Lehniger Kurt Issleib 《Journal of organometallic chemistry》1983,250(1):609-616
The complexes of type R2)2 (M = Pd, Pt) are readily deprotonated by n-Buli under various conditions yielding μ-C-bis-dilithiated species. The resulting carbanions are attacked by the electrophiles Mel, Me3SiCl and Ph2PCl to form the corresponding disubstituted derivatives. The reaction with AuCl . PPh3 yields heterobimetallic complexes with two different MC σ-bonds. The compounds obtained are analytically and spectroscopically characterized. 相似文献
14.
Romanescu C Manzhos S Boldovsky D Clarke J Loock HP 《The Journal of chemical physics》2004,120(2):767-777
The velocity-map imaging technique was used to record photoelectron and photofragment ion images of HCl following two-photon excitation of the E Sigma(+)(0+), V 1Sigma(+)(0+) (nu=9,10,11) states and subsequent ionization. The images allowed us to determine the branching ratios between autoionization and dissociation channels for the different intermediate states. These branching ratios can be explained on the basis of intermediate state electron configurations, since the configuration largely prohibits direct ionization in a one-electron process, and competition between autoionization and dissociation into H* (n=2)+Cl and H+Cl*(4s,4p,3d) is observed. From a fit to the vibrationally resolved photoelectron spectrum of HCl+ it is apparent that a single superexcited state acts as a gateway to autoionization and dissociation into H+Cl*(4s). Potential reconstruction of the superexcited state to autoionization was undertaken and from a comparison of different autoionization models it appears most likely that the gateway state is a purely repulsive and low-n Rydberg state with a (4Pi) ion core. 相似文献
15.
Hans-Georg Schmarr Birgit Maas Armin Mosandl Stephan Bihler Hans-Peter Neukom Konrad Grob 《Journal of separation science》1991,14(5):317-321
An unusual peak defocusing effect influencing chromatographic performance over a limited range of elution temperatures is described for hexakis(2,6-di-O-pentyl-3-O-acetyl)-α-cyclodextrin stationary phase. Since this phenomenon is likely to be dependent on minor details of the cyclodextrin molecule, full assignment of the 1H- and 13C-NMR-spectra are given. 相似文献
16.
Jakob Boelsterli Ursula Eggnauer Esteban Pombo-Villar Hans-Peter Weber Malcolm Walkinshaw Robert O. Gould 《Helvetica chimica acta》1992,75(2):507-512
The l-azabicyclo[2.2.1]heptan-3-exo-ol ( 2 ) was resolved by fractional crystallisation of its hydrogen tartrate salts. The enantiomers (+)- and (?)- 2 were oxidised to the ketones (?)- 4 and (+)- 4 , respectively (Scheme). CD spectroscopy suggested that (?)- 4 possesses the (1R,4S)-configuration. This absolute configuration was confirmed by single-crystal X-ray diffraction of the derivative (+)-(1R,4R)-3-(1,3-dithian-2-ylidene)-1-azabicyclo [2.2.1]-heptane ((+)- 5 ). 相似文献
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Fulvene-Dieters: Synthesis, Structure Elucidation and Thermal Behaviour In contrast to earlier assumptions, thermal reaction of pure fulvene ( 1a ), 6-methylfulvene ( lb ) and 6, 6-dimethylfuivene ( 1c ) at 227deg; gives oligomeric mixtures consisting mainly of the endo-[4 + 2]-eycloaddition products 2a , 2b and 2c . Thermal reactivity of the fulvenes decreases strongly in the series 1a > 1b > 1c . While the dimers 2b and 2c equilibrate very easily in solution above room temperature with 1b and 1c , respectively, 2a equilibrates with the isomer 5a (? 1, 6-Dimethyliden3a α, 3bβ, 6a α, 6bβ-tetrahydro-1-H), 6 H-bi (cyclopentadienylen). This surprising rearrangement envolves a formal 1,3-shift of the 1, 2-dihydrofulvene-unit of 2a (s. Scheme 4). 相似文献
20.
Hans-Peter Ros Rolf Kyburz Nigel W. Preston Rex T. Gallagher I. Ralph C. Bick Manfred Hesse 《Helvetica chimica acta》1979,62(2):481-487
The revised structure 1 is put forward for peduncularine, the main alkaloid of Aristotelia peduncularis (Labill.) HOOK. F. (Elaeocarpaceae), on the basis of its spectroscopic properties and those of its degradation products, the Hofmann base 3 and the hydrogenation product 4 . Structure 1 represents the relative configuration of the alkaloid. Peduncularine belongs to the class of indole alkaloids with a monoterpene unit as the aliphatic portion. To our knowledge it constitutes the first example in which an isopropyl group has become detached from the terpene unit and occurs as a substituent on nitrogen. 相似文献