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The principal methods for the synthesis of 7-amino coumarins and their reactivities are described. The luminescence properties and generation characteristics of this important class of organic dyes are examined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 147–174, February, 1987.  相似文献   

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By reaction of 6-[N-(2-hydroxyethyl)-N-methyl]aminopurine ( 2a ) and of the corresponding 3-hydroxypropyl derivative 2b with thionyl chloride a bridge to N(1) is formed yielding 5 and 6 , respectively, whereas from 6-[N-(4-hydroxybutyl)-N-methyl]aminopurine ( 2c ) the 4-chlorobutyl compound 4 is obtained, which cyclizes in alkaline medium to the C(6)-N(7) bridged compound 7 . A related cyclization to 11a–11f is observed when 6-chloropurines are reacted with 3-alkyl-1,3-oxazolidines or 3-methyl-1,3-thiazolidine.  相似文献   

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The Raman and infrared spectra of gas phase Re(2)O(7) are reported. The experimental vibrational spectra of molecular Tc(2)O(7) and Re(2)O(7) are compared with calculated spectra. The results of these studies agree with a nonlinear M-O-M bridge for Tc(2)O(7) and Re(2)O(7). For infrared intensity calculations, the point charge approximation is used, while for the Raman calculations a combination of bond and atom polarizabilities is adopted. Pure Re(2)O(7) was prepared from rhenium wire, but attempts to prepare it from rhenium powder and oxygen always led to infrared spectra showing serious contamination from a species containing an -OH linkage. Detailed experiments identified this molecule as HReO(4), a unique transition metal analogue of the perhalic acids, and a partial infrared spectrum of this molecule is reported.  相似文献   

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Aryl(6-methyl-2-phenyl-7-indolizinyl)methanes were obtained by quaternization of aryl(-pyridyl)methanes with bromoacetophenone and subsequent cyclization of the quaternary salts with 40% potassium carbonate solution (the Chichibabin method). The stable 2, 5-dimethyl-4-(2,4-dimethylbenzyl)pyridinium benzoylmethylid, which was converted to an indolizine by the action of Al2O3, was isolated by the action of a 10% potassium carbonate solution on the corresponding quaternary salt. The ability of 3-unsubstituted indolizines to undergo protonation in both the 3 and 1 position was shown on the basis of the PMR spectra. The aryl(7-indolizinyl)methanes are selectively hydrogenated thoroughly over rhenium heptasulfide in the indolizine ring to give tetra or octahydro derivatives without involvement of the aryl groups. Data from the IR, PMR, and mass spectra are presented.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 646–649, May, 1977.  相似文献   

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Shing TK  So KH 《Organic letters》2011,13(11):2916-2919
First syntheses of C6,7 and C7 enantiopure cocaine analogues were achieved from D-(-)-ribose via a trans-acetonide controlled endo-selective intramolecular nitrone-alkene cycloaddition (INAC) as the key step. This synthetic scheme allows practical preparation of cocaine analogues for bioevaluation as potential candidates for the treatment of cocaine addiction and as potential conjugates for immunotherapy.  相似文献   

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This paper reports two lanthanide complexes of formula (C_9H_7)Ln(C_8H_8)·(THF)_2 whereLn is Pr or Nd,C_9H_7 is indenyl,and C_8H_8 is cyclooctatetraene (COT).The complexes were preparedby the reaction of LnCl_3 with K(C_9H_7) and K_2(C_8H_8) in THF.(C_9H_7)Pr(C_8H_8)·(THF)_2 crystallizes inTHF at - 15℃ in the monoclinic space group P2_1:with unit cell dimensions a=8.446(0),b=10.083(2),c=13.407(3),β=105.48(1)°,V=1100.43(35)~3,Dc=1.52g/cm~3 and Z=2.The final R valueis 0.033,R_w value is 0.030,respectively.In (C_9H_7)Pr(C_8H_8)·(THF)_2 a five-membered ring centroid ofC_9H_7,the C_8H_8 ring centroid and the two oxygen atoms from the two THF molecules form a distortedtetrahedral geometry around the metal.  相似文献   

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Tri(1-cyclohepta-2,4,6-trienyl)phosphane, P(C7H7)3, and Tetra(1-cyclohepta-2,4,6-trienyl)phosphonium Tetrafluoroborate, [P(C7H7)4]BF4 The reaction of tris(trimethylsilyl)phosphane, P(SiMe3)3, with tropylium bromide, C7H7+Br?, in polar solvents such as dichloromethane or tetrahydrofuran gives P(C7H7)3 ( 1 ) and [P(C7H7)4]Br ( 2a ). According to the X-ray crystallographic structure determinations, all 1-cyclohepta-2,4,6-trienyl substituents are present in the boat conformation in both P(C7H7)3 ( 1 ) and the phosphonium salt, [P(C7H7)4]BF4 ( 2b ). The boat-shaped C7H7 rings are significantly more flattened if the phosphorus occupies the axial rather than the equatorial position at the ring substituent. Addition of a chalcogen to the lone pair at the central phosphorus atom of 1 leads to the chalcogena-phosphoranes EP(C7H7)3 (E = O ( 3a ), S ( 3b ), Se ( 3c )). The new 1-cyclohepta-2,4,6-trienyl-phosphorus compounds 1, 2 b and 3a–c were characterized by their 1H, 13C, and 31P NMR spectra in C6D6 solution.  相似文献   

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From the reaction of cis-dichlorobis(triphenylphosphane)platinum(II) with the lithium compound obtained as the bromination product of 2-methylnaphthalene cis-bis(7-methylnaphth-1-yl)bis(triphenylphosphane)platinum(II) (6), has been isolated. The unexpected formation of 6 has been explained.  相似文献   

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Reaction of [Pt25-C5Me5)2(η-Br)3]3+(Br)3 with C5R5H (R = H,Me) in the presence of AgBF4 gives the first platinocenium dications, [Pt(η5-C5Me5)(η5-C5R5)]2+(BF4 )2. On electrochemical reduction, [pt(η5-C5Me5)2]2+ yields [Pt(η4-C5Me5H)(η2-C5Me5)]+ BF4. kw]Cyclopentadienyl; Metallocenes; Platinum; Electrochemistry  相似文献   

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A method has been developed for the synthesis of 1,3,7-triazapyrenes using the reaction of 6(7)-formyl-and 6(7)-benzoylperimidines with 1,3,5-triazines in PPA. Under these conditions, 6(7)-formylperimidine reacts with 2,4,6-trimethyl-1,3,5-triazine to give 6-hydroxy-1,3-diazapyrene. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1080–1084, July, 2008.  相似文献   

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Zusammenfassung Unter Verwendung von Imidazol als Base wurden 6 verschiedene Solvent-Formulierungen hergestellt und erprobt. Wir fanden bei allen Formulierungen eine stöchiometrische Reaktion mit Wasser. Sie sind deshalb als KF-Reagentien geeignet. Die Reagentien ermöglichen eine sehr schnelle Titration und geben stabile Endpunkte. Sie scheinen unbeschränkt lagerfähig zu sein.
Karl fischer reagents without pyridine (7)Two-component reagents containing imidazole
Summary Six different KF-reagents were prepared using imidazole as base component. All reagents give a stoichiometric reaction with water and can be used for the KF-titration. The reagents show a high speed of reaction and lead to stable endpoints. The shelflife seems to be unlimited.


Teil 6: Fresenius Z Anal Chem (1982) 310:423–426  相似文献   

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The complex (η5-C5H4CH3)Mn(NO)(PPh3)I has been prepared by the reaction of NaI with [(η5-C5H4CH3)Mn(NO)(CO)(PPh3)]+ and also by the reaction of [(η5-C5H4CH3)Mn(NO)(CO)2]+ with NaI followed by PPh3. This iodide compound reacts with NaCN to yield (η5-C5H4CH3)Mn(NO)(PPh3)CN which is ethylated by [(C2H5)3O]BF4 to yield [(η5-C5H4CH3)Mn(NO)(PPh3)(CNC2H5)]+. Both [(η5-C5H4CH3)Mn(NO)(CO)2]+ and [(η5-C5H4CH3)Mn(NO)(PPh3)(CO)]+ react with NaCN to yield [(η5-C5H4CH3)Mn(NO)(CN)2]?. This anion reacts with Ph3SnCl to yield cis-(η5-C5H4CH3)Mn(NO)(CN)2SnPh3 and with [(C2-H5)3O]BF4 to yield [(η5-C5H4CH3)Mn(NO)(CNC2H5)2]+. The reaction of (η5-C5-H4CH3)Mn(NO)(PPh3)I with AgBF4 in acetonitrile yields [(η5-C5H4CH3)Mn-(NO)(PPh3)(NCCH3)]+. The complex (η5-C5H4CH3)Mn(NO)(CO)I, produced in the reaction of [(η5-C5H4CH3)Mn(NO)(CO)2]+ with NaI, is not stable and decomposes to the dimeric complex (η5-C5H4CH3)2Mn2(NO)3I for which a reasonable structure is proposed. Similar dimers can be prepared from the other halide salts. The reaction of (η7-C7H7)Mo(CO)(PPh3)I with NaCN yields (η7-C7-H7)Mo(CO)(PPh3)CN which is ethylated by [(C2H5)3O]BF4 to yield [(η7-C7H7)-Mo(CO)(PPh3)(CNC2H5)]+. The interaction of this molybdenum halide complex with AgBF4 in acetonitrile and pyridine yields [(η7-C7H7)Mo(CO)(PPh3)-(NCCH3)]+ and [(η7-C7H7)Mo(CO)(PPh3)(NC5H5)]+, respectively. Both (η5-C5-H4CH3)Mn(NO)(PPh3)I and (η7-C7H7)Mo(CO)(PPh3)I are oxidized by NOPF6 to the respective 17-electron cations in acetonitrile at ?78°C but revert to the neutral halide complex at room temperature. This result is supported by electrochemical data.  相似文献   

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焦晓臻  姜英俊  谢平  梁晓天 《有机化学》2007,27(12):1537-1541
以4-戊烯酸及(R)-4-苯基-2-噁唑烷酮为起始原料, 以氯化镁在三乙胺和三甲基氯化硅存在下催化的(R)-4-苯基-3-戊烯酰基-2-噁唑烷酮的埃文斯(Evans)反式羟醛缩合反应为关键步骤, 经9步反应合成了(-)-7(R)-羟罗汉脂素, 其光谱数据与文献报道的天然产物一致.  相似文献   

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We report the photon-stimulated desorption of negative ions induced by direct dipolar dissociation and dissociative electron attachment. The photon-stimulated desorption of F(-) ions from CF(3)Cl physisorbed on a Si(111)-7x7 surface at 30 K in the photon energy range 12-35 eV was studied. The F(-) ion yield exhibits four resonances, at 12.8, 16.2, 19.5, and 22.3 eV, quite unlike the gas phase photodissociation cross section. The intensities of these resonances depend strongly on the CF(3)Cl coverage in a manner which varies from peak to peak. The resonances at 19.5 and 22.3 eV, which have a significant enhancement in the monolayer regime, are due to electron mediated dipolar dissociation of adsorbed CF(3)Cl molecules. The enhancement is attributed to surface electron attachment following molecular excitation. A significant enhancement in the monolayer regime has also been observed for the resonances at 12.8 and 16.2 eV. These two resonances are ascribable to a combination of electron mediated dipolar dissociation and dissociative electron attachment driven by photoelectrons generated in the neighboring molecules.  相似文献   

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