700-44-7Relevant articles and documents
ESIPT emission behavior of methoxy-substituted 2-hydroxyphenylbenzimidazole isomers
Takagi, Koji,Yamada, Yoshihiro,Fukuda, Ryoichi,Ehara, Masahiro,Takeuchi, Daisuke
, p. 5923 - 5928 (2018)
Three 2-hydroxyphenylbenzimidazole isomers 1, 2, and 3 with the methoxy group at the 6, 4, and 3-position, respectively, were synthesized in short steps. 1 exhibited ESIPT emission irrespective of the solvent character. While 2 only showed ESIPT emission in THF and MeCN, LE emission was also observed in MeOH and a THF/water mixed solvent. These phenomena were nicely accounted for by intramolecular hydrogen bonding interactions. The fluorescence spectra of 3 always consisted of two emission bands and it exhibited strange behavior particularly in protic solvents. The fluorescence emissions in the solid state were found to be closely related to the crystal packing structure.
[4+2] cycloaddition of intermediates generated from arynes and DMF
Yoshioka, Eito,Tamenaga, Hirofumi,Miyabe, Hideto
, p. 1402 - 1405 (2014)
The trapping reaction of the transient intermediate ortho-quinone methides, generated by the insertion of arynes into a carbon-oxygen double bond of DMF, with dienophiles was investigated. The [4+2] cycloaddition products were obtained when the diesters of acetylenedicarboxylic acid were employed as dienophiles.
Evaluation of 2-(piperidine-1-yl)-ethyl (PIP) as a protecting group for phenols: Stability to ortho-lithiation conditions and boiling concentrated hydrobromic acid, orthogonality with most common protecting group classes, and deprotection via Cope elimination or by mild Lewis acids
Norén, Rolf
, (2021/04/07)
A new protecting group, 2-(piperidine-1-yl)-ethyl (PIP), was evaluated as a protecting group for phenols. The PIP group was stable to ortho-lithiation conditions and refluxing with concentrated hydrobromic acid. Deprotection was accomplished by two routes, oxidation to N-oxides followed by Cope elimination (CE) and subsequent hydrolysis or ozonolysis of the vinyl ether or one-step deprotection by BBr3?Me2S. The PIP group is orthogonal to the O-benzyl, O-acetyl, O-t-butyldiphenylsilyl, O-methyl, O-p-methoxybenzyl, O-allyl, O-tetrahydropyranyl and N-t-butoxy carbonyl groups. The CE step was systematically studied and was found to give higher yields when the reaction was performed in the presence of silylating agents.
Synthesis and structure-activity relationship studies of hydrazide-hydrazones as inhibitors of laccase from trametes versicolor
Giurg, Miros?aw,Maniak, Halina,Matyja, Konrad,Talma, Micha?,Trusek, Anna
supporting information, (2020/03/23)
A series of hydrazide-hydrazones 1-3, the imine derivatives of hydrazides and aldehydes bearing benzene rings, were screened as inhibitors of laccase from Trametes versicolor. Laccase is a copper-containing enzyme which inhibition might prevent or reduce the activity of the plant pathogens that produce it in various biochemical processes. The kinetic and molecular modeling studies were performed and for selected compounds, the docking results were discussed. Seven 4-hydroxybenzhydrazide (4-HBAH) derivatives exhibited micromolar activity Ki = 24-674 μM with the predicted and desirable competitive type of inhibition. The structure-activity relationship (SAR) analysis revealed that a slim salicylic aldehyde framework had a pivotal role in stabilization of the molecules near the substrate docking site. Furthermore, the presence of phenyl and bulky tert-butyl substituents in position 3 in salicylic aldehyde fragment favored strong interaction with the substrate-binding pocket in laccase. Both 3- and 4-HBAH derivatives containing larger 3-tert-butyl-5-methyl- or 3,5-di-tert-butyl-2-hydroxy-benzylidene unit, did not bind to the active site of laccase and, interestingly, acted as non-competitive (Ki = 32.0 μM) or uncompetitive (Ki = 17.9 μM) inhibitors, respectively. From the easily available laccase inhibitors only sodium azide, harmful to environment and non-specific, was over 6 times more active than the above compounds.
Direct formylation of fluorine-containing aromatics with dichloromethyl alkyl ethers
Warashina, Takuya,Matsuura, Daisuke,Kimura, Yoshikazu
, p. 587 - 593 (2019/07/22)
Formylations of fluorine-containing aromatic compounds with dichloromethyl alkyl ethers have been investigated. Dichloromethyl propyl ether and dichloromethyl butyl ether have been applied for the formylation of fluorine-containing anisoles to give the corresponding aldehydes in good yields. Application of these ethers is preferable to that of methyl ether, which is prepared from volatile methyl formate. Reaction of fluorine-containing phenols with these dichloromethyl alkyl ethers did not give salicylaldehyde derivatives, leading instead to corresponding aryl formates in high yields. A plausible mechanism is discussed.
Iridium- and Rhodium-Catalyzed Directed C-H Heteroarylation of Benzaldehydes with Benziodoxolone Hypervalent Iodine Reagents
Grenet, Erwann,Waser, Jér?me
supporting information, p. 1473 - 1476 (2018/03/09)
The C-H heteroarylation of benzaldehydes with indoles and pyrroles was realized using the benziodoxolone hypervalent iodine reagents indole- and pyrroleBX. Functionalization of the aldehyde C-H bond using either an o-hydroxy or amino directing group and catalyzed by an iridium or a rhodium complex allowed the synthesis of salicyloylindoles and (2-sulfonamino)benzoylindoles, respectively, with good to excellent yields (74-98%). This new transformation could be carried out under mild conditions (rt to 40 °C) and tolerated a broad range of functionalities, such as ethers, halogens, carbonyls, or nitro groups.
Remarkable Ability of the Benzylidene Ligand To Control Initiation of Hoveyda–Grubbs Metathesis Catalysts
Basak, Tymoteusz,Grudzień, Krzysztof,Barbasiewicz, Micha?
supporting information, p. 3513 - 3523 (2016/07/29)
The structure of the chelating benzylidene ligand offers the unique ability to control the initiation of Hoveyda–Grubbs metathesis catalysts. Apart from steric and electronic effects acting on the step involving opening of the chelate ring, changes related to the following ligand-exchange process may also play a critical role. Our mechanistic model reveals that ligands substituted at the 6-position of the benzylidene ring enter the metathesis cycle in a nonoptimal chelating conformation, and thus the coordination number of the ruthenium center transiently increases to six (associative mechanism). In effect, the synthesis and initiation of the catalysts becomes difficult, and the energy barrier of the ligand-exchange process is controlled by the structure of the coordinating OR group. Moreover, we explain how isomeric naphthalene ligands affect the catalytic performance by an indivisible combination of steric and π-electron delocalization effects.
Exploring the Strength of the H-Bond in Synthetic Models for Heme Proteins: The Importance of the N?H Acidity of the Distal Base
Alberti, Mariza N.,Polyhach, Yevhen,Tzirakis, Manolis D.,T?dtli, Laura,Jeschke, Gunnar,Diederich, Fran?ois
supporting information, p. 10194 - 10202 (2016/07/19)
The distal hydrogen bond (H-bond) in dioxygen-binding proteins is crucial for the discrimination of O2with respect to CO or NO. We report the preparation and characterization of a series of ZnIIporphyrins, with one of three meso-phenyl rings bearing both an alkyl-tethered proximal imidazole ligand and a heterocyclic distal H-bond donor connected by a rigid acetylene spacer. Previously, we had validated the corresponding CoIIcomplexes as synthetic model systems for dioxygen-binding heme proteins and demonstrated the structural requirements for proper distal H-bonding to CoII-bound dioxygen. Here, we systematically vary the H-bond donor ability of the distal heterocycles, as predicted based on pKavalues. The H-bond in the dioxygen adducts of the CoIIporphyrins was directly measured by Q-band Davies-ENDOR spectroscopy. It was shown that the strength of the hyperfine coupling between the dioxygen radical and the distal H-atom increases with enhanced acidity of the H-bond donor.
Formylation of electron-rich aromatic rings mediated by dichloromethyl methyl ether and TiCl4: Scope and limitations
Ramos-Tomillero, Iván,Paradís-Bas, Marta,De Pinho Ribeiro Moreira, Ibério,Bofill, Josep María,Nicolás, Ernesto,Albericio, Fernando
supporting information, p. 5409 - 5422 (2015/05/13)
Here the aromatic formylation mediated by TiCl4 and dichloromethyl methyl ether previously described by our group has been explored for a wide range of aromatic rings, including phenols, methoxy- and methylbenzenes, as an excellent way to produce aromatic aldehydes. Here we determine that the regioselectivity of this process is highly promoted by the coordination between the atoms present in the aromatic moiety and those in the metal core.
Rational design and synthesis of novel 2-(substituted-2H-chromen-3-yl)-5-aryl-1H-imidazole derivatives as an anti-angiogenesis and anti-cancer agent
Gudipudi, Gopinath,Sagurthi, Someswar R.,Perugu, Shyam,Achaiah,Krupadanam, G. L. David
, p. 56489 - 56501 (2015/02/05)
Based on earlier proven pharmacophore analogues of cancer a novel 2-(substituted-2H-chromen-3-yl)-5-aryl-1H-imidazoles (13-16) were rationally designed and synthesized by the reaction of chromene-3-carboxylic acids (10a-d) with substituted acyl bromides in the presence of TEA followed by refluxing with NH4OAc in toluene. Compounds 13-16 were screened in vitro for the inhibition of KRAS/Wnt and their anti-angiogenesis properties. Compound 16f has been identified as a potent anti-angiogenesis molecule, which can be considered as a new lead structure. The molecular docking analysis displayed the higher binding affinity of 16f with KRAS, Wnt and VEGF.
