119979-38-3Relevant academic research and scientific papers
Facile construction of thermo-responsive Pickering emulsion for esterification reaction in phase transfer catalysis system
Lei, Manjun,Shen, Yifeng,Sun, Jie,Yang, Lei,Yang, Lihui,Zhao, Qiangqiang,Zhao, Xiao
, (2021)
In this paper, a thermo-responsive Pickering emulsion (PE) is constructed for the esterification reaction in the phase transfer catalysis (PTC) system. Silica nanoparticle modified by alkyl polyoxyethylene ether and tetrabutylammonium bromide (TBAB) is the highly efficient thermo-responsive Pickering emulsifier to stabilize the diisopropyl ketone-in-water emulsion. PEs can keep stable at room temperature for 3 days and demulsify only in the condition of elevated temperature and agitation, which causes the easy product separation and aqueous phase recycling. The adsorption of TBA+ and nonionic surfactant via electrostatic interaction and hydrogen bonding, respectively, can increase the hydrophobicity and the emulsifying capacity of silica nanoparticle. The ion-pair of TBA+ and reactant anion is generated and can be transferred into the organic phase, initiating the bond-forming reaction. The modifying effect of polyoxyethylene ether is weakened with the increase of temperature due to the loss of the hydrogen bonding interaction, resulting in the demulsification of PEs. Moreover, the cloud point of polyoxyethylene ether is the temperature for the complete separation of two phases. In this PTC system, the conversion rate for the esterification can reach to 92 % and the aqueous phase can be reused at least 5 times without sacrifice of the catalytic activity, demonstrating the potential application in industry.
Supramolecular photochemistry of encapsulated caged: Ortho -nitrobenzyl triggers
Kamatham, Nareshbabu,Raj, A. Mohan,Givens, Richard S.,Da Silva, José P.,Ramamurthy
, p. 2411 - 2420 (2019/10/21)
ortho-Nitrobenzyl (oNB) triggers have been extensively used to release various molecules of interest. However, the toxicity and reactivity of the spent chromophore, o-nitrosobenzaldehyde, remains an unaddressed difficulty. In this study we have applied the well-established supramolecular photochemical concepts to retain the spent trigger o-nitrosobenzaldehyde within the organic capsule after release of water-soluble acids and alcohols. The sequestering power of organic capsules for spent chromophores during photorelease from ortho-nitrobenzyl esters, ethers and alcohols is demonstrated with several examples.
Photoactivable heterocyclic cages in a comparative release study of butyric acid as a model drug
Piloto, Ana M.,Hungerford, Graham,Sutter, Jens U.,Soares, Ana M.S.,Costa, Susana P.G.,Gonc?alves, M. Sameiro T.
, p. 44 - 53 (2015/02/19)
Aiming: at the improvement of the photorelease of butyric acid - a model carboxylic acid drug, a set of heteroaromatic compounds based on acridine, naphtho[2,1-b]pyran, 3H-benzopyran fused julolidine and thioxo-naphtho[2,1-b]pyran were evaluated as benzyl-type phototriggers, in comparison with the well-known o-nitrobenzyl group. The corresponding ester cages were irradiated in a photochemical reactor at 254, 300, 350 and 419 nm, in two solvent systems (methanol or acetonitrile in 80:20 mixtures with HEPES buffer). Photolysis studies showed that, for some of the cages, the release of the active molecule occurred with short irradiation times using 419 nm. Time-resolved fluorescence was used to elucidate their photophysical properties and determine the decay kinetics. Studies were also carried out to assess the suitability of using two-photon excitation to address these compounds, which is advantageous if their use in biological systems is to be considered.
Nitrobenzyl esters as potential conjugated alkylating and differentiation promoting agents: Antitumor effect in vivo
Wakselman,Cerutti,Chany
, p. 519 - 526 (2007/10/02)
A series of ortho and para-nitrobenzyl esters of short chain fatty acids (C2 to C5) and of the lipophilic aminoacid, L-valine, and some other o-nitrobenzylated products were prepared. Bioreductive or hydrolytic cleavages of these compounds could release both differentiation promoting agents such as butyric acid and electrophilic moieties able to alkylate DNA. The antitumor effects of these compounds, either alone and/or associated with an immunostimulating agent (corynebacterium parvum, CP) or interferon (IFN) treatment, was studied using the 180 TG Crocker Sarcoma grafted onto Swiss mice. Based on the mean survival time and the final survival rate, the most active compounds used alone were the o-nitrobenzyl acetate and the 0-nitrobenzyl butyrate. Previous stimulation of the immune competent cells by CP before antitumor treatment increased the efficiency of most of the nitrobenzylated derivatives studied. The association with IFN did not significantly improve the antitumor effect.
