Bridged cyanine dyes. Part 1. 1-(N-methyl-4-pyridinio)-3-(N-methylpyridylene)cyclopenta-1,4-dienes

1,3-Bis(N-methyl-4-pyridinio)propane is condensed with a series of α-diketones to form deep red monocyanine dyes 8 . In strongly acidic solutions C-protonation occurs at the central carbon atom. A similar condensation with α-ketoesters yields zwitterionic cyanines 12 with extinction coefficients exceeding 10⁵.     

(Z)-2-(1H-咪唑-1-基)-1-(2,3,4-三甲氧基)苯乙酮肟酯的设计与合成

三甲基苯乙酮肟;立体异构体;(Z)-2-(1H-咪唑-1-基)-1-(2;3;4-三甲氧基)苯乙酮肟酯的设计与合成     

Preparation,molecular structures,and characteristic properties of (E)-1-(2-furyl)- and (E)-1-(2-thienyl)-2-(3-guaiazulenyl)ethylenes and (E)-1-(3-furyl)- and (E)-1-(3-thienyl)-2-(3-guaiazulenyl)ethylenes

Wittig reactions of 2-furaldehyde (20) [and thiophene-2-carbaldehyde (21)] with (3-guaiazulenylmethyl)triphenylphosphonium bromide (19) in ethanol containing NaOEt at 25 °C for 24 h under argon give (E)-1-(2-furyl)-2-(3-guaiazulenyl)ethylene (22E) and (E)-1-(2-thienyl)-2-(3-guaiazulenyl)ethylene (23E) in 53 and 36% yields. Similarly, Wittig reactions of 3-furaldehyde (29) [and thiophene-3-carbaldehyde (30)] with 19 under the same reaction conditions as for 20 and 21 afford (E)-1-(3-furyl)-2-(3-guaiazulenyl)ethylene (31E) and (E)-1-(3-thienyl)-2-(3-guaiazulenyl)ethylene (32E) in 32 and 46% yields. Molecular structures and characteristic properties as well as preparation of the title E (i.e., one of the geometrical isomers) forms, with a view to comparative study, are reported. Moreover, reactions of those conjugated π-electron systems with TCNE (=tetracyanoethylene) in benzene [and in DMF (=N,N-dimethylformamide)] at 25 °C for 24 h under argon yield unique products, possessing interesting molecular structures, respectively, whose characteristic properties and crystal structures are documented, also.     

Palladium-catalyzed allylic oxidation of 1-(p-toluenesulfonyl)-2-propene and 1-(trimethylsilyl)-1-(p-toluenesulfonyl)-2-propene

The course of palladium-catalyzed oxidation of a terminal alkene by t-BuOOH or by O₂/H₂O is greatly modified when the allylic carbon bears a p-toluenesulfonyl substituent, and allylic oxidation results. Mechanistic explanations of this observation are proposed.     

4-(Arylaminothiocarbonyl)-1-(1-o-methoxyphenylcarbamido)-ethylpiperazines as anticonvulsants

Several 4-(arylaminothiocarbonyl)-1-(1-o-methoxyphenylcarbamido)-ethylpiperazines were synthesized and evaluated for their anticonvulsant activity against pentylenetetrazol-induced seizures in mice. The ability of substituted piperazines to inhibit in vitro respiratory activity of rat brain homogenates was also determined to study their structure-activity relationship.     

Arylsulfonylureido- und Arylsulfonylamidoacyl-Derivate von Hydroxy- und Oxo-cycloalkanen als potentielle Antidiabetica, 5. Mitt.: (1R)-, (1S)-, (1RS)-3-endo-Tosylureido-borneol und (1R)-3-endo-Tosylureido-isoborneol

Ohne Zusammenfassung

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Arylsulfonylureido- and Arylsulfonylamidoacyl Derivatives of Hydroxy cycloalkanes as potential antidiabetica (V): (1R)-, (1S)-, and (1RS)-3-endo-tosylureido borneol and (1R)-3-endo-tosylureido isoborneol