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Organic Reactivity in Microemulsions
Published in Promod Kumar, K. L. Mittal, Handbook of Microemulsion Science and Technology, 2018
Clifford A. Bunton, Laurence S. Romsted
Microemulsions ofTer the intriguing capability of cosolubilizing high concentrations of water-insoluble and water-soluble reactants, and many studies of chemical reactivity in microemulsions have focused on potential large-scale applications of these systems as reaction media. For example, the high solubilizing power of microemulsions has led several groups to use them for the destruction of toxic materials, e.g., the still dangerous and unstable stockpiles of chemical weapons in Russia and the United States [29,30], because some chemical agents are only sparingly soluble in water, aqueous micelles, or aqueous organic solvents [20]. The highly toxic and very hydrophobic blister agent mustard gas (1) and less toxic model compounds are rapidly destroyed by hydrolysis or oxidation, but their solubilities in water are generally too low for rapid reaction under mild conditions. Their reactions are very rapid in microemulsions that contain hypochlorite ion and tert-butyl alcohol, which generates tert-butyl hypochlorite, the probable oxidant. The high solubility of very hydrophobic chlorosulfides in microemulsions is of key importance in this reaction [31,32].
Selective Organic Synthesis – How Can Solids Help?
Published in Mike G. Scaros, Michael L. Prunier, Catalysis of Organic Reactions, 2017
Initial experiments showed that dichloramine-T (DCT), which does not react significantly with toluene at room temperature in the absence of a solid, could effect quantitative ring chlorination in the presence of a Chromatographic grade of silica gel supplied by BDH (eq.1).2 Other chlorinating agents, such as tert-butyl hypochlorite, were also effective.4 The reaction was very clean and the chlorotoluenes were easily isolated since the by-products remained adsorbed on the silica, but the isomer distribution was unexceptional, being close to statistical, as found in traditional ring-chlorination reactions.
Can Origanum be a hope for cancer treatment? A review on the potential of Origanum species in preventing and treating cancers
Published in International Journal of Environmental Health Research, 2023
Carvacrol (2-methyl-5-(1-methylethyl)-phenol), a phenolic compound and isomer of thymol, is abundant in plants containing thyme and oregano (Suntres et al. 2015). Slightly soluble in water, but well soluble in alcohol and ether, carvacrol is volatile and shows alkaline properties. As a powerful antiseptic and germicidal, it is included in the composition of preparations used in medicine and orally. Artificial carvacrol is produced from carvone or p-cymene synthesized from d-limonene. Carvacrol is synthesized by many methods, such as sulfonation of p-cymene (Phillips 1924), chlorination of α-pinene with tert-butyl hypochlorite (Ritter and Ginsburg 1950) and alkali fusion or the aromatization of carvone using sulfuric acid and amberlyst 15 catalyst (Gozzi et al. 2009). A method based on the alkylation of o-cresol with propylene or isopropyl alcohol over solid acid catalysts was reported as a cleaner and greener process in the chemical synthesis of carvacrol. In the aforementioned method, carvacrol can be obtained up to 82% yield at 180°C (Yadav and Kamble 2009).
Selenium chlorides in the domino process of the regiospecific allyl chlorination of betulin and diacetylbetulin
Published in Journal of Sulfur Chemistry, 2020
I. V. Bodrikov, Yu. A. Kurskii, A. A. Chiyanov, A. Yu. Subbotin, A. S. Shavirin, N. V. Anderson
Recently, in a preliminary report [7], we described a new direction of the reaction of selenium chlorides with betulin and diacetylbetulin demonstrating regiospecific allyl chlorination of these substrates. According to our data [8], halogenation of betulin and diacetylbetulin with N-chloro-, N-bromo-, and N-iodosuccinimides leads to a mixture of vinylic and allylic isomers. Thus, when they are chlorinated with N-chlorosuccinimide or tert-butyl hypochlorite, the main products are unsaturated vinylic chlorides of the Z- and E-structures, and the content of the allylic isomer does not exceed 30% [8,9]. As confirmed by X-ray analysis, allylic and vinylic isomers of diacetylbetulin crystallized jointly [9]. The developing of selective methods for the synthesis of betulin derivatives is due to the complexity of separating its isomers, since they have similar physical characteristics, as well as the low content of the allylic isomer in the mixture.