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Synthesis of Betenamine and of Betalaine Model Substances For comparisons of color, spectroscopic properties, pKa values, and stabilities, a number of model substances containing the 1,7-diazaheptamethinium chromophore 8 of the yellow and red betalaine plant pigments were prepared by the thermal or photolytic ring opening of simple pyridine derivatives (such as 2 and 14-16 ), followed by the introduction of amines. Among the novel compounds prepared were betenamine perchlorate ( 5 ), the ‘naked’ ring system of the beet-pigment betanine ( C ) as well as two 1,7-diazaheptamethinium salts 25 and 27 with terminal amono acids. The synthesis of 5 started with 4-(2-aminoethyl)pyridine ( 1 ) and proceeded via 2 , ring opening with indoline to 4 , saponification, and intramolecular amine replacement (Scheme 1). The syntheses of 25 and 27 involved only one step, namely ring opening of γ-picoline using (S)-cyclodopa ( 24 ) and (S)-proline ( 26 ), respectively (Scheme 3).  相似文献   

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MeSbCl2 (1) and SbCl3 give the adduct MeSbCl2·0.6SbCl3 (1a). MeSbBr2 (2) reacts with NaI to form MeSbI2 (3) and with Cr(CO)5 THF to give Me(Br)2SbCr(CO)5 (4). The crystal structures of 1a, 2 and 4 are reported. Derivatives of methyl antimony are obtained by reaction of 2 or 4 with Mg in tetrahydrofuran.  相似文献   

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A six-membered and two seven-membered cycloalkynes, namely 1 – 3, are generated by matrix photolyses of the corresponding cyclopropenones 4 – 6 at about 15 K and characterized by spectroscopic means and in two cases by identification of the trimerization products 9 and 10.  相似文献   

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Triphenylgallane reacts with alkyl- and aryl-thiols, respectively, with formation of the corresponding diphenylalkyl- and diphenylaryl-thiogallanes. Spectra and some physical and chemical properties of the new compounds are given. The results of the X-ray structure determination of diphenylethylthiogallane are discussed.  相似文献   

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Associated -phosphinodiborane, (-H2PB2H5) n , is formed in the reaction of H2P(BH3)2Na with HCl in diethyl ether solution at –96°C. The formation of B–H–B bridges is demonstrated by IR and11B-NMR spectra. (-H2PB2H5) n decomposes thermally to diborane and polymeric phosphinoborane analogous to -H2NB2H5. Other phosphorus substituted -phosphinodiboranes associated via B–H–B bridges are formed in the reaction of the salts (CH3)PH(BH3)2Li, (CH3)2P(BH3)2Li, andPhPH(BH3)2Li with HCl.

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Herrn Professor Dr.E. Hayek zum 70. Geburtstag gewidmet.  相似文献   

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