4360-63-8Relevant articles and documents
Electron Spin Resonance Spectra of Free Radicals. Part 2. Radicals formed by Hydrogen Abstraction from Cyclic and Acyclic Fluoro-acetals
Lee, Kheng H.,Brumby, Steven
, p. 1071 - 1074 (1983)
Free radicals formed during the photolysis of solutions containing di-t-butyl peroxide and fluoro-acetals such as 1,1-diethoxy-2-fluoroethane and substituted 1,3-dioxolanes, have been studied by e.s.r. spectroscopy.Only the radicals formed initially by hydrogen abstraction were detected, although product analysis by g.c.-m.s. indicated that certain of the cyclic radicals rearranged to acyclic species.The e.s.r. parameters are discussed in relation to the preferred conformations of the radicals.
Kinetics and mechanism of bromination of cyclic acetals with 1,4-dioxane dibromide
Kotlyar,Kamalov,Savranskaya,Bogatskii
, p. 120 - 123 (1981)
It is shown that the reactivities of cyclic formals in the case of bromination with dioxane dibromide increase in the order 1,3-dioxepane > 1,3-dioxalane ? 1,3-dioxane, which is explained not only by steric factors but also by the ease of cleavage of the C4-O3 bond of the dioxacyclane ring. The bromination of cyclic acetals takes place through prior enolization of the cyclic acetal with subsequent electrophilic addition of bromine to the double bond.
Preparation methods of doxofylline
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Paragraph 0055-0057, (2017/01/23)
The invention discloses preparation methods of doxofylline. The preparation methods include the steps: under the action of an acid-binding agent, carrying out a condensation reaction of theophylline and halogenated acetaldehyde dimethyl acetal in a polar solvent, to obtain an intermediate 7-(2,2-dimethoxy ethyl)theophylline; and then, with soluble hydrosulfate as a catalyst, carrying out a condensation cyclization reaction of the intermediate 7-(2,2-dimethoxy ethyl)theophylline with ethylene glycol in a solvent, to obtain doxofylline; or, firstly, carrying out a condensation cyclization reaction of halogenated acetaldehyde dimethyl acetal and ethylene glycol to obtain halogenated acetaldehyde ethylene acetal, and carrying out a condensation reaction with theophylline, to obtain doxofylline. The soluble hydrosulfate is used as the catalyst and replaces conventional p-toluenesulfonic acid, moreover, and anisole and other solvents are used for replacing methylbenzene used in a conventional reaction route, so that under a condition of ensuring high yield of the product, the toxicity of the solution in the synthesis reaction is reduced, and the difficult problem that residual toxicity easily exists in the finished product is solved.
Effect of Crown Ethers on Bromination of 2-Methyl-1,3-dioxacycloalkanes with N-Bromosuccinimide
Kotlyar,Pluzhnik-Gladyr',Zlotskii
, p. 283 - 284 (2007/10/03)
Crown ethers exert a pronounced catalytic effect on bromination of 2-methyl-1,3-dioxacycloalkanes with N-bromosuccinimide and increase the yield of 2-bromomethyl derivatives.