6317-85-7Relevant articles and documents
An eco-friendly method for synthesis of symmetrical and unsymmetrical benzoin derivatives
Safari, Javad,Arani, Naimeh Moshtael,Isfahani, Anousheh Ramezan
experimental part, p. 495 - 498 (2011/12/21)
A rapid, highly efficient and mild green synthesis of symmetrical and unsymmetrical benzoin derivatives was achieved from the reaction of benzaldehyde derivatives with potassium cyanide in dimethyl sulfoxide under argon gas and ultrasound. This simple method affords benzoin derivatives at room temperature in short reaction times with high yield and purity.
Red-emitting dyes with photophysical and photochemical properties controlled by pH
Novakova, Veronika,Miletin, Miroslav,Kopecky, Kamil,Zimcik, Petr
scheme or table, p. 14273 - 14282 (2012/01/06)
New unsymmetrical zinc azaphthalocyanines, bearing one substituted aniline as a peripheral substituent, were prepared by using a statistical condensation approach. Both fluorescence and singlet oxygen quantum yields were extremely low in DMF (φFΔF=0. 22-0.29, φΔ=0.40-0.59, respectively). This behavior was attributed to the deactivation of excited states by intramolecular charge transfer from a donor site (aniline), which was blocked after protonation in acidic media. In the protonated form, all of the compounds efficiently emitted light with λem in the region of 662-675 nm. The investigated compounds were anchored to dioleoylphosphatidylcholine (DOPC) unilamellar vesicles and showed response to buffer pH. They were highly fluorescent at low pH values and almost nonfluorescent in neutral solutions. The pKa values were determined in DOPC vesicles and ranged between 2.2 and 4.2.
Influence of protonation of peripheral substituents on photophysical and photochemical properties of tetrapyrazinoporphyrazines
Novakova, Veronika,M?rkved, Eva H.,Miletin, Miroslav,Zimcik, Petr
experimental part, p. 582 - 591 (2011/10/03)
Octasubstituted zinc tetrapyrazinoporphyrazines with four N,N-dimethylaminophenyls and four phenyl or pyridin-3-yl substituents were synthesized and fully characterized. Their fluorescence quantum yields in DMF or pyridine were very low, almost undetectable, as a consequence of ultrafast intramolecular charge transfer. Titration of their DMF solutions with sulfuric acid led to increase of the fluorescence quantum yields by two orders of magnitude when the full protonation of peripheral substituents was achieved. Intramolecular charge transfer is no longer a favorable way of excited-state relaxation at full protonation of N,N-dimethylaminophenyl substituents because of loss of donor centers (free electron pair on its nitrogen). Similarly, singlet oxygen quantum yields also increased by two orders of magnitude when sulfuric acid was added to tetrapyrazinoporphyrazine solutions in DMF. Protonation at azomethine nitrogens of tetrapyrazinoporphyrazine macrocycle was observed at higher acid concentrations and it led to considerable decrease of fluorescence quantum yields. Octaphenyl zinc tetrapyrazinoporphyrazine and octa(pyridin-3-yl) zinc tetrapyrazinoporphyrazine were used as controls without intramolecular charge transfer. Their fluorescence and singlet oxygen quantum yields were high in DMF and decreased at higher concentrations of sulfuric acid due to protonation of azomethine nitrogens. The results suggest that the photophysical and photochemical properties of studied compounds may be controlled by changes of pH of medium.
Mass-spectral behavior and thermal stability of hetaryl analogs of unsymmetrical benzoins
Ivonin,Mazepa,Lapandin
, p. 451 - 457 (2008/02/01)
The main path in the mass-spectral dissociation of the hetaryl analogs of unsymmetrical benzoins is β-fragmentation with cleavage of the central C-C bond. Here, the strongest peak in the mass spectra of α-benzoins is the peak of the hydroxymethylhetaryl cation, and in β-benzoins it is the peak of the hetaroyl cation. The thermal α → β isomerization of the hetaryl analogs of benzoin was studied. In the case of indole and pyrrole derivatives the formation of polyheterocyclic systems is observed. 2006 Springer Science+Business Media, Inc.
One-pot synthesis of phenytoin analogs
Mahmoodi,Emadi
, p. 377 - 382 (2007/10/03)
A series of phenytoin analogs (5,5-diphenylimidazolidine-2,4-dione or 5,5-diphenyl-hydantoin) were synthesized in 65-75% yield from the corresponding substituted benzils. The same products were also obtained directly from α-hydroxy ketones via one-pot procedure.
66. Synthese und Reaktionen des 5--2,2-dimethyl-4-phenyl-3-oxazolins
Foricher, Joseph,Montavon, Francois,Pfoertner, Karl-Heinz,Schoenholzer, Peter
, p. 592 - 599 (2007/10/02)
Synthesis and Reactions of 5--2,2-dimethyl-4-phenyl-3-oxazoline.The title compound 8 has been synthesized in a one-pot reaction of 4'-(dimethylamino)benzoin (4) with 2-propanone and NH3.The preparation of the intermediate 4 from 3 is the first example of an acid-catalyzed transformation of the stable benzoin 3 into the corresponding less stable benzoin 4.Structures and yields of various by-products occuring under different reaction conditions during the synthesis of 8 from 4 are given.The O-atom of the 3-oxazoline ring in 8 could be replaced by S from P2S5 yielding the 3-thiazoline 14.Separation of the enantiomers of the racemate 8 could only be performed by transforming them into the trimethylanilinium salts 8b and 8c of (-)- and (+)-10-camphorsulfonic acid, respectively.Solid NaOAc in boiling toluene caused the precipitation of the 10-camphorsulfonic acids from the quaternary ammonium salts as sodium salts and the removing of the third methyl group from the quaternary ammonium salts as AcOMe to give the enantiomers (-)-(5S)-8 and (+)-(5R)-8.Their absolute configurations are deduced from an X-ray analysis of 8b.
