The novel catalytic reaction for bromolactonization of alkenoic acids is reported. When iodobenzene is used as recyclable catalyst in combination with Oxone® as terminal oxidant, the cyclization of various 4‐pentenoic acids with sodium bromide is easily carried out in CF3CH2OH at room temperature and giving five‐membered bromolactones in good yields. J. Heterocyclic Chem., 2011.
Benzodiazepines are one group of psychoactive drugs widely detected in water environments, and their persistence during conventional wastewater treatment has raised great concerns. Here we investigated the degradation of 17 benzodiazepines in water by UV/H2O2 treatment. The results showed that the UV/H2O2 treatment significantly increased the degradation of 17 benzodiazepines in phosphate buffer solutions at pH 7.0. This can be attributed to the high reactivity of hydroxyl radicals (·OH) towards benzodiazepines with second-order rate constants of 3.48 × 109 M−1 s−1–2.44 × 1010 M−1 s−1. The degradation of alprazolam, a typical benzodiazepine, during the UV/H2O2 treatment was increased with the increasing H2O2 dosage. The solution pH influenced the alprazolam degradation significantly, with the highest degradation at pH 7.0. Water matrix, such as anions (Cl−, HCO3−, NO3−) and humic acid, decreased the degradation of alprazolam by UV/H2O2 treatment. Based on the degradation products identified using quadrupole time-of-flight mass spectrometer, the degradation mechanisms of alprazolam by UV/H2O2 treatment were proposed, and hydroxylation induced by ·OH was the main reaction pathway. The degradation of 17 benzodiazepines by UV/H2O2 treatment in wastewater treatment plant effluent and river water was lower than that in phosphate buffer solutions. The results showed that the benzodiazepine psychoactive drugs in natural water can be effectively removed by the UV/H2O2 treatment.
An Effective Catalytic α-Phosphoryloxylation of Ketones with Iodobenzene. -The reaction proceeds through intermediate formation of hypervalent hydroxyiodo compounds. -(PU, Y.; GAO, L.; LIU, H.; YAN*, J.; Synthesis 2012, 1, 99-103, http://dx.
An effective catalytic method for a-phosphoryloxylation of ketones is reported. When ketones were reacted with phosphates in the presence of iodobenzene as the recyclable catalyst and mchloroperbenzoic acid as the terminal oxidant in acetonitrile at room temperature, the a-phosphoryloxylation of ketones took place easily and the corresponding keto phosphates were obtained in moderate to good yields.Organic hypervalent iodine reagents have found broad applications in organic chemistry and are frequently used in organic synthesis due to similar chemical properties and reactivities to those of mercury(II), thallium(III), and lead(IV), but without the toxic and environmental problems of these heavy metal congeners. 1 Among these hypervalent iodine reagents, [hydroxy(tosyloxy)iodo]benzene (Koser's reagent) is the most popular and useful reagent for the direct a-tosyloxylation of ketones, and the prepared a-tosyloxyketones are important strategic precursors for the construction of various heteroaromatics. 2 However, the analogue reaction for preparation of the important keto phosphates by the direct a-phosphoryloxylation of ketones with stoichiometric hypervalent iodine reagents has been rather limited. 3Recently, the catalytic utilization of hypervalent iodine reagents is increasing in importance, with the growing interest in the development of environmentally benign synthetic transformations. 4 In these catalytic reactions, a catalytic amount of an iodine-containing molecule together with a stoichiometric oxidant are used. The oxidant generates the hypervalent iodine reagent in situ, and after the oxidative transformation, the reduced iodine-containing molecule is re-oxidized. Ochiai and co-workers reported the a-acetoxylation of ketones with iodobenzene as catalyst and m-chloroperbenzoic acid (m-CPBA) as oxidant. 5 Kita's group demonstrated the catalytic spirocyclization of phenol and amide derivatives using hypervalent iodine reagents as catalysts. 6 The iodobenzene-catalyzed a-tosyloxylation of ketones with m-CPBA in the presence of p-toluenesulfonic acid has also received considerable attention more recently. 7 However, to our knowledge, the similar catalytic a-phosphoryloxylation of ketones has not been reported before. In order to extend the scope of catalytic application of hypervalent iodine reagents in organic synthesis, we have investigated the aphosphoryloxylation of ketones with iodobenzene as catalyst. Herein, we would like to report the novel and effective catalytic a-phosphoryloxylation of ketones.The selected model reaction was carried out with acetophenone, diphenyl phosphate, m-CPBA, and a catalytic amount of iodobenzene in several organic solvents at room temperature (Table 1). When acetophenone was reacted with equimolar amounts of diphenyl phosphate and m-CPBA in the presence of 0.1 equivalent of iodobenzene in acetonitrile at room temperature for 72 hours, the desired product a-phosphoryloxyacetophenone was isolated in 60% of yield (Table 1, entry 1). It was found that when more diphenyl phospha...
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