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81.
Conditions have been found for the efficient palladium mediated cyclisation-carbonylation of bromodienes to give gamma,lambda-unsaturated acids. 相似文献
82.
The problem of early failure modelling has been discussed comprehensively. Present models have been discussed and new models are suggested. A drawback of failure rate not being finite at t = 0 for some of the present models is eliminated in the suggested models. 相似文献
83.
84.
[reaction: see text] Cyclopropanation of allylic tertiary amines using the Simmons-Smith reagent has been achieved by employing chelating groups in close proximity to the amine. The chelating groups promote cyclopropanation at the expense of N-ylide formation. Using pseudoephedrine as the chelating group, high diastereoselectivity is observed. 相似文献
85.
Zahoor Abbas Manoj Kumar Hardeep Singh Tuli Essam M. Janahi Shafiul Haque Steve Harakeh Kuldeep Dhama Pallvi Aggarwal Mehmet Varol Anita Rani Shashi Sharma 《Molecules (Basel, Switzerland)》2022,27(24)
Quercetin is one of the most powerful bioactive dietary flavonoids. The in vivo biological study of quercetin is extremely difficult due to its very low solubility. However, diorganotin complexes of quercetin are more useful when contrasted with quercetin due to increased solubility. In the present study, quercetin, substituted biguanide synthesized in the form of Schiff base and its di-alkyl/aryl tin (IV) complexes were obtained by condensing Schiff base with respective di-alkyl/aryl tin (IV) dichloride. Advanced analytical techniques were used for structural elucidation. The results of biological screening against Gram-positive/Gram-negative bacteria and fungi showed that these diorganotin (IV) derivatives act as potent antimicrobial agents. The in silico investigation with dihydropteroate (DHPS) disclosed a large ligand–receptor interaction and revealed a strong relationship between the natural exercises and computational molecular docking results. 相似文献
86.
The synthesis of imidazolinium salts from the reaction of formamidines and (2-bromoethyl)diphenylsulfonium triflate is described. A variety of symmetrical and unsymmetrical imidazolinium triflate salts were synthesized in high yield in short reaction times under mild conditions. Aromatic and aliphatic N-substituents work well. The reaction is proposed to proceed via generation of a vinyl sulfonium salt intermediate from the bromoethylsulfonium triflate. 相似文献
87.
StephenP. Thomas VarinderK. Aggarwal 《Angewandte Chemie (International ed. in English)》2009,48(11):1896-1898
A breakthrough in the asymmetric hydroboration of notoriously difficult 1,1‐disubstituted alkenes using a new family of highly effective hydroboration reagents is described (see scheme). The intermediate boranes can be oxidized to alcohols or used in Suzuki–Miyaura cross‐coupling reactions.
88.
Ravi Aggarwal Durairaj Baskaran 《Journal of polymer science. Part A, Polymer chemistry》2011,49(23):5049-5056
Hydrated sodium montmorillonite (Na‐clay) has been used as a catalyst support for the heterogeneous atom transfer radical polymerization of benzyl methacrylate in the presence of various concentrations of water, reducing agent, and CuBr2 in anisole at ambient temperature. The polymerization was promoted via reduction of CuII to CuI through the addition of sodium ascorbate (NaAsc) as a reducing agent in aqueous solution. The polymerizaton proceeded in a controlled manner and produced poly(benzyl methacylate) with moderately narrow molecular weight distribution (MWD) when performed under optimum conditions of hydration (10 wt % ≤ H2O/Na‐clay ≤ 21 wt %) and reducing agent (0.15 ≤ [NaAsc]/[I] ≤ 0.23). The polymerization was uncontrolled if hydration and NaAsc exceed above their optimum range of concentrations. Apparent rate of the polymerization (kapp) increased in the presence of decane–anisole (1/3, v/v) mixture solvent. Selective adsorption of decane at the interfaces of the hydrated clay was attributed for the rate enhancement due to increased polymer and hydrophobic interface interaction. The polymerization progressed in a controlled manner as confirmed by the first‐order time‐conversion plot, linear increase in molecular weights, and moderately narrow MWDs over conversion. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
89.
90.
α‐Tosyloxyketones (2), readily accessible through hypervalent iodine oxidation of enolizable ketones (1) using [hydroxy(tosyloxy)iodo]benzene (HTIB) in acetonitrile, exclusively generates the 6‐arylimidazo[2,1‐b]thiazoles (4) on treatment with commercially available 2‐aminothiazole (3). 相似文献