- The impact of cation structure upon the acidity of triazolium salts in dimethyl sulfoxide
-
A series of triazolium salts, selected for their varying electronic and steric properties, were prepared and their pKa values were determined in DMSO at 25 °C using the bracketing indicator method. The effect of each systematic structural variation upon the acidity of the triazolium cation has been considered, in particular examining the effects of systematically altering electronic properties, quantified through the use of Hammett σ parameters. The first pKa value for an azolium salt that generates a mesionic carbene is also reported. These new data allow for the selection of appropriate bases for the deprotonation of such triazolium salts and the potential to correlate the pKa values determined herein with the nucleophilicity of the corresponding carbenes.
- Konstandaras, Nicholas,Dunn, Michelle H.,Guerry, Max S.,Barnett, Christopher D.,Cole, Marcus L.,Harper, Jason B.
-
-
- Efficient synthesis of tertiary acyclic amides by the Chapman rearrangement of aryl benzimidates in ionic liquids
-
The Chapman rearrangement of aryl N-arylbenzimidates to tertiary acyclic amides is accelerated in ionic liquids and proceeds at lower temperatures as 120-190°C.
- Epishina, Margarita A.,Kulikov, Alexander S.,Ignat'Ev, Nikolai V.,Schulte, Michael,Makhova, Nina N.
-
p. 126 - 128
(2015/04/14)
-
- Functionalization of boron diiminates with unique optical properties: Multicolor tuning of crystallization-induced emission and introduction into the main chain of conjugated polymers
-
In this article, we report the unique optical characteristics of boron diiminates in the solid states. We synthesized the boron diiminates exhibiting aggregation-induced emission (AIE). From the series of optical measurements, it was revealed that the optical properties in the solid state should be originated from the suppression of the molecular motions of the boron diiminate units. The emission colors were modulated by the substitution effects (λPL,crystal = 448-602 nm, λPL,amorphous = 478-645 nm). Strong phosphorescence was observed from some boron diiminates deriving from the effects of two imine groups. Notably, we found some of boron diiminates showed crystallization-induced emission (CIE) properties derived from the packing differences from crystalline to amorphous states. The 15-fold emission enhancement was observed by the crystallization (φPL,crystal = 0.59, φPL,amorphous = 0.04). Next, we conjugated boron diiminates with fluorene. The synthesized polymers showed good solubility in the common solvents, film formability, and thermal stability. In addition, because of the expansion of main-chain conjugation, the peak shifts to longer wavelength regions were observed in the absorption/emission spectra of the polymers comparing to those of the corresponding boron diiminate monomers (λabs = 374-407 nm, λPL = 509-628 nm). Furthermore, the absorption and the emission intensities were enhanced via the light-harvesting effect by the conjugation with fluorene. Finally, we also demonstrated the dynamic reversible alterations of the optical properties of the polymer thin films by exposing to acidic or basic vapors.
- Yoshii, Ryousuke,Hirose, Amane,Tanaka, Kazuo,Chujo, Yoshiki
-
p. 18131 - 18139
(2015/02/19)
-
- 5-Imino-1,2,4-thiadiazoles: First small molecules As substrate competitive inhibitors of glycogen synthase kinase 3
-
Cumulative evidence strongly supports that glycogen synthase kinase-3 (GSK-3) is a pathogenic molecule when it is up-dysregulated, emerging as an important therapeutic target in severe unmet human diseases. GSK-3 specific inhibitors might be promising effective drugs for the treatment of devastating pathologies such as neurodegenerative diseases, stroke, and mood disorders. As GSK-3 has the ability to phosphorylate primed substrates, small molecules able to bind to this site should be perfect drug candidates, able to partially block the activity of the enzyme over some specific substrates. Here, we report substituted 5-imino-1,2,4-thiadiazoles as the first small molecules able to inhibit GSK-3 in a substrate competitive manner. These compounds are cell permeable, able to decrease inflammatory activation and to selectively differentiate neural stem cells. Overall, 5-imino-1,2,4-thiadiazoles are presented here as new molecules able to decrease neuronal cell death and to increase endogenous neurogenesis blocking the GSK-3 substrate site
- Palomo, Valle,Perez, Daniel I.,Perez, Concepcion,Morales-Garcia, Jose A.,Soteras, Ignacio,Alonso-Gil, Sandra,Encinas, Arantxa,Castro, Ana,Campillo, Nuria E.,Perez-Castillo, Ana,Gil, Carmen,Martinez, Ana
-
p. 1645 - 1661
(2012/04/04)
-
- Synthesis and basicity of 4-amino-2-phenylquinazolines
-
A new group of 6-and 7-substituted compounds of 4-amino-2-phenylquinazoline were synthesized by reaction of N-arylbenzimidoyl chlorides with cyanamide in the presence of TiCl4. The products were identified by spectroscopic methods, their dissoc
- Zielinski, Wojciech,Kudelko, Agnieszka
-
p. 895 - 899
(2007/10/03)
-
- Synthesis of 4-Aminoquinazoline Derivatives
-
The reaction of N-phenylimidoyl chlorides (2) with cyanamide and N,N-dimethylcyanamide (4) was studied.At the first stage, linear products like 1-amino-1-chloro-3,5-diphenyl-2,4-diaza-1,3-butadienes (6) were obtained.They underwent cyclization to 4-aminoq
- Zielinski, W.,Mazik, M.
-
p. 489 - 498
(2007/10/02)
-
- REACTIONS OF IMIDIC ACID DERIVATIVES WITH NUCLEOPHILIC REAGENTS. THE EFFECT OF WATER ON THE AMINOLYSIS RATE OF IMIDOYL CHLORIDES IN ORGANIC MEDIA. MECHANISMS IN THE "BOUNDARY" REGIONS
-
The effect of water (as a catalyst) on the rate of the reaction of N-arylbenzimidoyl chlorides C6H5CCl=NC6H4R with 4-dimethylaminopyridine in acetonitrile, propylene carbonate, γ-butyrolactone, benzonitrile, methylene chloride, dioxane (R = 4-Cl), and ace
- Saveelova, V. A.,Taran, N. A.,Drizhd, L. P.
-
p. 2020 - 2030
(2007/10/02)
-
- Intramolecular Reaction Between Nitro and Carbodi-imide Groups; A New Synthesis of 2-Arylbenzotriazoles
-
1-(2-Nitrophenyl)-5-phenyltetrazole (5b) decomposes when heated to give nitrogen, carbon dioxide, and 2-phenylbenzotriazole (6) in high yield.This new molecular rearrangement proceeds via 2-nitrophenyl(phenyl)carbodi-imide (8).Other precursors of this carbodi-imide, i.e. oxadiazolone (10), oxadiazolethione (11), oxathiadiazole 2-oxide (12), and the aminimide (16), and carbodi-imide itself, all give 2-phenylbenzotriazole (6) on thermolysis, the last three in high yield.This reaction is general for diarylcarbodi-imides with an ortho nitro group, and their precursors, and it provides a useful new route to 2-arylbenzotriazoles.A sequence of electrocyclic ring closing and opening reactions (Scheme 5) is proposed as the mechanism of this process.The key intermediate, 2-phenyl-1,2,4-benzotriazin-3-one 1-oxide (19) has been isolated from a careful thermolysis of (12) in toluene; in solution it is in reversible equlibrium with the ring-opened form (20).This new nitro-carbodi-imide group interaction has been extended to the more stable nitrobiphenyl(phenyl)carbodi-imide (25) and nitronaphthyl(phenyl)carbodi-imide (24) which, on flash vacuum pyrolysis, give benzimidazophenanthridine (29) and benzindazole 1-oxide (32) respectively, in new rearrangements.
- Houghton, Peter G.,Pipe, David F.,Rees, Charles W.
-
p. 1471 - 1480
(2007/10/02)
-
- Studies of N-Acyl-2-pyridinecarboxanilides. Preparation by Various Reactions Sequences and Reaction with Hydrogen Chloride to give Acyl Imidate Hydrochlorides through an Intramolecular N -> O Acyl Migration
-
The preparation of N-acyl-2-pyridinecarboxanilides from imidoyl chlorides and salts of carboxylic acids is reported.Only small amounts of the same N-acylimides are obtained from acylations of 2-pyridinecarboxanilides with acyl chlorides and a base.Treatme
- Moerkved, Eva H.
-
p. 313 - 318
(2007/10/02)
-