1024-41-5Relevant academic research and scientific papers
Polymer enzyme conjugates as chiral ligands for sharpless dihydroxylation of alkenes in organic solvents
Konieczny, Stefan,Leurs, Melanie,Tiller, Joerg C.
, p. 83 - 90 (2015)
Conjugates of enzymes and poly(2-methyloxazoline) were used as organosoluble amphiphilic polymer nanocontainers for dissolving osmate, thereby converting the enzymes into organosoluble artificial metalloenzymes. These were shown to catalyze the dihydroxylation of different alkenes with high enantio-selectivity The highest selectivities, found for osmate complexed with laccase polymer-enzyme conjugates (PECs), even exceed those of classical Sharpless catalysts.
Synthesis of alkyl sulfonates from sulfonic acids or sodium sulfonates using solid-phase bound reagents
Vignola, Nicola,Dahmen, Stefan,Enders, Dieter,Br?se, Stefan
, p. 7833 - 7836 (2001)
An efficient and selective method for the synthesis of sulfonic esters from sulfonic acids or sodium sulfonates using polymer-bound primary triazenes based upon the T2* linker has been developed. The purities of the esters obtained are usually greater tha
Chemoselective and scalable preparation of alkyl tosylates under solvent-free conditions
Kazemi, Foad,Massah, Ahmad R.,Javaherian, Mohammad
, p. 5083 - 5087 (2007)
The improved method for the efficient tosylation of alcohols has been reported using two procedures (A and B). Procedure A: methanol, ethanol, benzyl alcohols, and valuable ethylene glycols can be converted into their corresponding alkyl tosylates in very fast, simple, and efficient grinding method using potassium carbonate as solid base. Other primary and secondary alcohols need to add potassium hydroxide to reaction mixture (procedure B). High selectivity of tosylation was observed for these two procedures. Scale up ability was found in this method even in 100 mmol of substrate. The present method is the example of solid-state tosylation using tosyl chloride, and is a green chemical process due to solvent-free conditions.
Influence of Alkoxy Groups on Rates of Acetal Hydrolysis and Tosylate Solvolysis: Electrostatic Stabilization of Developing Oxocarbenium Ion Intermediates and Neighboring-Group Participation to Form Oxonium Ions
Garcia, Angie,Otte, Douglas A. L.,Salamant, Walter A.,Sanzone, Jillian R.,Woerpel
, p. 4470 - 4480 (2015)
The hydrolysis of 4-alkoxy-substituted acetals was accelerated by about 20-fold compared to that of sterically comparable substrates that do not have an alkoxy group. Rate accelerations are largest when the two functional groups are linked by a flexible cyclic tether. When controlled for the inductive destabilization, an alkoxy group can accelerate acetal hydrolysis by up to 200-fold. The difference in rates of acetal hydrolysis between a substrate where the alkoxy group was tethered to the acetal group by a five-membered ring compared to one where it was tethered by an eight-membered ring was less than 100-fold, suggesting that fused-ring intermediates were not formed. By comparison, the difference in rates of solvolysis of structurally related tosylates were nearly 106-fold between the five- and eight-membered ring series. This observation implicates neighboring-group participation in the solvolysis of tosylates but not in the hydrolysis of acetals. The acceleration of acetal hydrolysis by an alkoxy group is better explained by electrostatic stabilization of intermediates that accumulate positive charge at the acetal carbon atom. (Chemical Presented).
Acceleration of acetal hydrolysis by remote alkoxy groups: Evidence for electrostatic effects on the formation of oxocarbenium ions
Garcia, Angie,Otte, Douglas A. L.,Sanzone, Jillian R.,Woerpel, K. A.,Salamant, Walter A.
, p. 3061 - 3064 (2015)
In contrast to observations with carbohydrates, experiments with 4-alkoxy-substituted acetals indicate that an alkoxy group can accelerate acetal hydrolysis by up to 20-fold compared to substrates without an alkoxy group. The acceleration of ionization in more flexible acetals can be up to 200-fold when compensated for inductive effects.
Synthesis of a leopolic acid-inspired tetramic acid with antimicrobial activity against multidrug-resistant bacteria
Mattio, Luce,Musso, Loana,Scaglioni, Leonardo,Pinto, Andrea,Martino, Piera Anna,Dallavalle, Sabrina
, p. 2482 - 2487 (2018)
The increasing emergence of multidrug-resistant pathogens is one of the biggest threats to human health and food security. The discovery of new antibacterials, and in particular the finding of new scaffolds, is an imperative goal to stay ahead of the evolution of antibiotic resistance. Herein we report the synthesis of a 3-decyltetramic acid analogue of the ureido dipeptide natural antibiotic leopolic acid A. The key step in the synthetic strategy is an intramolecular Lacey-Dieckmann cyclization reaction of a linear precursor to obtain the desired 3-alkyl-substituted tetramic acid core. The synthesized analogue is more effective than the parent leopolic acid A against Gram-positive (Staphylococcus pseudintermedius) and Gram-negative (E. coli) bacteria (MIC 8 μg/mL and 64 μg/mL, respectively). Interestingly, the compound shows a significant activity against Staphylococcus pseudintermedius strains expressing a multidrug-resistant phenotype (average MIC 32 μg/mL on 30 strains tested). These results suggest that this molecule can be considered a promising starting point for the development of a novel class of antibacterial agents active also against resistant strains.
An efficient one-pot conversion of THP and TMS ethers to sulfonate esters using FeCl3-montmorillonite K-10 clay
Movassagh, Barahman,Shokri, Salman
, p. 763 - 765 (2005)
Various tetrahydropyranyl and trimethylsilyl ethers are efficiently transformed into the corresponding sulfonate esters with sulfonyl chlorides in the presence of FeCl3-Montmorillonite K-10 clay.
Direct facile tetrahydrofuranylation of alcohols in p-TsCl/NaH/THF system
Yu,Hui
, p. 2037 - 2042 (1995)
Several alcohols were converted in excellent yields into their 2-tetrahydrofuranyl-ethers in the presence of p-TsCl and NaH in THF under mild conditions. A radical process was proposed.
Methanesulfinylation of Benzyl Halides with Dimethyl Sulfoxide
Fu, Duo,Dong, Jun,Du, Hongguang,Xu, Jiaxi
, p. 2752 - 2758 (2020/01/31)
A phenyltrimethylammonium tribromide-mediated nucleophilic substitution/oxygen transformation reaction of benzyl halides with DMSO has been developed. In this transition-metal-free reaction, DMSO acts as not only a solvent but also a "S(O)Me" source, thus providing a convenient method for the efficient and direct synthesis of various benzyl methyl sulfoxides.
Carbon glucoside sodium glucose transport protein body 2 inhibitor
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Paragraph 0038; 0127-0130, (2018/07/30)
The invention relates to a carbon glucoside sodium glucose transport protein body 2 inhibitor, a preparation method and an application of the inhibitor. The carbon glucoside sodium glucose transport protein body 2 inhibitor has a structure as shown in general formula (I) as shown in the specification.
