31769-45-6Relevant academic research and scientific papers
Photochromism of the complex between 4′-(2-hydroxyethoxy)-7- hydroxyflavylium and β-cyclodextrin, studied by 1H NMR, UV-Vis, continuous irradiation and circular dichroism
Gago, Sandra,Basílio, Nuno,Fernandes, Ana,Freitas, Victor,Quintas, Alexandre,Pina, Fernando
, p. 106 - 112 (2014)
The network of chemical reactions of the compound 4′-(2- hydroxyethoxy)-7-hydroxyflavylium and its photochromic properties were studied in the absence and presence of β-cyclodextrin. The system was characterized by 1H NMR, UV-Vis, continuous irradiation and circular dichroism. In the presence of β-cyclodextrin 4.8 mM the pK′a is reduced to 2.2. The association constants with β-cyclodextrin, follow the order trans-chalcone > quinoidal base > flavylium cation, respectively 1.7 × 103 M-1; 5.6 × 102 M -1; ≈0. The rate of inter-conversion of the network species increases in the presence of β-cyclodextrin circa 2.6 times. The appearance of an induced circular dichroism signal of trans-chalcone inside the β-cyclodextrin is described for the first time. It gives information about the position of the guest inside the host and allows the calculation of the respective association constant.
Chemoselective and ligand-free aerobic oxidation of benzylic alcohols to carbonyl compounds using alumina-supported mesoporous nickel nanoparticle as an efficient recyclable heterogeneous catalyst
Das, Asit Kumar,Nandy, Sneha,Bhar, Sanjay
, (2021/05/10)
An economically efficient and operationally simple ligand-free protocol for the chemoselective oxidation of benzylic alcohols to carbonyl compounds has been developed using alumina-supported nickel nanoparticles as a stable recyclable heterogeneous catalyst along with potassium tert-butoxide in the presence of aerial oxygen as an eco-friendly oxidant. The aliphatic alcohols remained unaffected under the present condition. Excellent chemoselectivity has also been demonstrated through intermolecular and intramolecular competition experiments. This protocol accommodates a diverse range of substituents with the tolerance of various sensitive moieties during the reaction. The catalyst could be recovered by filtration and reused consecutively without any significant loss in the catalytic activity. Moreover, the heterogeneity of the catalyst has also been established by the “hot filtration method (Sheldon's test)”.
Design, synthesis, biological evaluation and inhibition mechanism of 3-/4-alkoxy phenylethylidenethiosemicarbazides as new, potent and safe tyrosinase inhibitors
Liao, Bing,Mai, Yuliang,Shi, Huahong,Song, Senchuan,Wang, Fei
, p. 369 - 379 (2020/05/14)
Tyrosinase plays important roles in many different disease related processes, and the development of its inhibitors is particularly important in biotechnology. In this study, thirty-nine 3-/4-alkoxyphenylethyli-denethiosemicarbazides were synthesized as novel tyrosinase inhibitors based on structure-based molecular design. Our experimental results demonstrated that thirty-one of them possess remarkable tyrosinase inhibitory activities with IC50 value below 1μM, and 5a, 6e, 6g and 6t did not display any toxicity to 293T cell line at the concentration of 1000μmol/L. According to the inhibitory activities, several compounds were selected for detail investigation on the structure–activity relationships (SARs), mechanisms of enzyme inhibition, inhibitory kinetics and cytotoxicity. In particular, the interaction between the selected inhibitors and the active center of tyrosinase was considered and discussed in detail based on their structural characteristics. Taken together, the results presented here demonstrated that the newly designed compounds are promising candidates for the treatment of tyrosinase-related disorders and further development of them may have significant contribution in biomedical science.
Functionalization of the chalcone scaffold for the discovery of novel lead compounds targeting fungal infections
Bonvicini, Francesca,Gentilomi, Giovanna A.,Bressan, Francesca,Gobbi, Silvia,Rampa, Angela,Bisi, Alessandra,Belluti, Federica
, (2019/02/01)
The occurrence of invasive fungal infections represents a substantial threat to human health that is particularly serious in immunocompromised patients. The limited number of antifungal agents, devoid of unwanted toxic effects, has resulted in an increased demand for new drugs. Herein, the chalcone framework was functionalized to develop new antifungal agents able to interfere with cell growth and with the infection process. Thus, a small library of chalcone-based analogues was evaluated in vitro against C. albicans ATCC 10231 and a number of compounds strongly inhibited yeast growth at non-cytotoxic concentrations. Among these, 5 and 7 interfered with the expression of two key virulence factors in C. albicans pathogenesis, namely, hyphae and biofilm formation, while 28 emerged as a potent and broad spectrum antifungal agent, enabling the inhibition of the tested Candida spp. and non-Candida species. Indeed, these compounds combine two modes of action by selectively interfering with growth and, as an added value, weakening microbial virulence. Overall, these compounds could be regarded as promising antifungal candidates worthy of deeper investigation. They also provide a chemical platform through which to perform an optimization process, addressed at improving potency and correcting liabilities.
A molybdenum based metallomicellar catalyst for controlled and chemoselective oxidation of activated alcohols in aqueous medium
Thiruvengetam, Prabaharan,Chakravarthy, Rajan Deepan,Chand, Dillip Kumar
, p. 123 - 133 (2019/07/19)
A surfactant based oxodiperoxo molybdenum complex, which could activate molecular oxygen, has been employed as a catalyst for controlled oxidation of benzylic alcohols to corresponding carbonyls. The oxidation reactions were carried out under aqueous environment, however, in the absence of any extraneous base or co-catalyst. Sensitive/oxidizable functional groups like cyano, sulfide, hydroxyl, aryl-hydroxyl, alkene (internal/terminal), alkyne (internal/terminal), and acetal were tolerated during the transformations. Such selectivity is attributed to the mild nature of the catalyst. The methodology could also be scaled-up for multi-gram synthesis and the protocol is likely to find practical use since it requires an inexpensive recyclable-catalyst and easily available oxidant (under green conditions). A plausible mechanism is proposed with the help of preliminary computational study.
Chemoselective and Metal-Free Synthesis of Aryl Esters from the Corresponding Benzylic Alcohols in Aqueous Medium Using TBHP/TBAI as an Efficient Catalytic System
Nandy, Sneha,Ghatak, Avishek,Das, Asit Kumar,Bhar, Sanjay
, p. 2208 - 2212 (2018/10/02)
A novel and transition-metal-free strategy has been developed for the synthesis of aryl esters starting from corresponding benzylic primary alcohols as the exclusive substrates using tert -butyl hydroperoxide (TBHP) as a terminal oxidant in the presence of catalytic amount of tetrabutylammonium iodide (TBAI) and imidazole, where the aliphatic alcohols remained unaffected. These reactions are highly chemoselective and associated with high yield and wide applicability accommodating a wide range of substituents. Excellent chemoselectivity has also been demonstrated through intramolecular competition experiments. This protocol can be considered as an important analogue of Tishchenko reaction using benzylic alcohols as the substrates instead of benzaldehydes.
Synthesis and antibacterial activity of 3-benzylamide derivatives as FtsZ inhibitors
Hu, Zhongping,Zhang, Shasha,Zhou, Weicheng,Ma, Xiang,Xiang, Guangya
supporting information, p. 1854 - 1858 (2017/04/04)
The emergence and spread of multidrug-resistant strains of the human pathological bacteria are generating a threat to public health worldwide. In the current study, a series of PC190723 derivatives was synthesized and investigated for their antimicrobial activity. The compounds exhibited good activity against several Gram-positive bacteria as determined by comparison of diameters of the zone of inhibition of test compounds and standard antibiotics. Compound 9 with a fluorine substitution on the phenyl ring showed the best antibacterial activity in the series against M. smegmatis with the zone ratio of 0.62, and against S. aureus with the zone ratio of 0.44. The results from this study indicate that based on the unique 3-methoxybenzamide pharmacophore, compound 9 may represent a promising lead candidate against Gram-positive bacteria that are worthy of further investigation
Dual-emissive difluoroboron naphthyl-phenyl β-diketonate polylactide materials: Effects of heavy atom placement and polymer molecular weight
Samonina-Kosicka, Jelena,Derosa, Christopher A.,Morris, William A.,Fan, Ziyi,Fraser, Cassandra L.
, p. 3736 - 3746 (2014/06/24)
Luminescent materials are important for imaging and sensing. Aromatic difluoroboron β-diketonate complexes (BF2bdks) are classic fluorescent molecules that have been explored as photochemical reagents, two-photon dyes, and oxygen sensors. A series of BF2bdks with naphthyl and phenyl groups was synthesized, and photophysical properties were investigated in both methylene chloride and poly(lactic acid) (PLA). Polymer molecular weight and dye attachment site along with bromide heavy atom placement were varied to tune optical properties of dye-PLA materials. Systems without heavy atoms have long phosphorescence lifetimes, which is useful for lifetime-based oxygen sensing. Bromine substitution on the naphthyl ring resulted in intense, clearly distinguishable fluorescence and phosphorescence peaks important for ratiometric oxygen sensing and imaging.
Copper(ii)-catalyzed C-O coupling of aryl bromides with aliphatic diols: Synthesis of ethers, phenols, and benzo-fused cyclic ethers
Liu, Yajun,Park, Se Kyung,Xiao, Yan,Chae, Junghyun
supporting information, p. 4747 - 4753 (2014/06/24)
A highly efficient copper-catalyzed C-O cross-coupling reaction between aryl bromides and aliphatic diols has been developed employing a cheaper, more efficient, and easily removable copper(ii) catalyst. A broad range of aryl bromides were coupled with aliphatic diols of different lengths using 5 mol% CuCl2 and 3 equivalents of K2CO3 in the absence of any other ligands or solvents to afford the corresponding hydroxyalkyl aryl ethers in good to excellent yields. In this newly developed protocol, aliphatic diols have multilateral functions as coupling reactants, ligands, and solvents. The resulting hydroxyalkyl aryl ethers were further readily converted into the corresponding phenols, presenting a valuable alternative way to phenols from aryl bromides. Furthermore, it was demonstrated that they are useful intermediates for more advanced molecules such as benzofurans and benzo-fused cyclic ethers. This journal is
COMPOSITION FOR DIAGNOSIS OF AMYLOID-RELATED DISEASE
-
, (2010/12/29)
There is provided a composition comprising a compound represented by general formula (I), wherein Rl represents a 5-iodothiophen-2-yl group or the like, and R2 represents a 4-dimethylaminophenyl group or the like. This composition is useful for diagnosis of an amyloid-related disease such as Alzheimer's disease because the compound has high binding specificity to amyloid β protein, high permeability through the blood-brain barrier, and a property of being rapidly eliminated from sites other than senile plaques in the brain.
