Preparation Of Cyclic Acetals Research Articles

Preparation of cyclic acetals and gem-dichlorocyclopropanes based on 1,2-dichloromethylbenzol

Using 2,2-dimethyl-4-hydroxymethyl-1,3-dioxolane (sol-ketal) and 1,2-dichlomethylbenzene under the conditions of phase transfer catalysis, mono- and diesters containing cycloacetal fragments were synthesized. Also, with the help of dichloride, in the presence of benzene, mono- and diesters of allyl alcohol were obtained. Dichlorocyclopropanation of unsaturated ethers using chloroform, alkali and catamine AB catalyst made it possible to obtain compounds containing gem-dichlorocyclopropane fragments. O-alkylation of the sol-ketal with 1-[(alloxy)methyl]-2-(chloromethyl)benzene (mono-derivative of allyl alcohol) was used to synthesize an ether combining in its structure 1,3-dioxolane and gem-dichlorocyclopropane fragments simultaneously. The obtained substances were analyzed and confirmed by mass spectrometry («Chromatek-Kristall» instrument with Nist research database) and NMR spectroscopy («Bruker instrument»). It was found that among a number of compounds obtained, only 4-{[(2-{[(2,2-dichlorocyclopropyl) methoxy]methyl}-benzyl)oxy] methyl}-2,2-dimethyl-1,3-dioxolane exhibits cytological activity against the cell lines HEK293, SH-SY5Y, MCF-7 and A549.

ChemInform Abstract: Sulfonated Charcoal, a Mild and Efficient Reagent for the Preparation of Cyclic Acetals, Dithioacetals, and Benzodioxepins.

ChemInform Abstract: Sulfonated Charcoal, a Mild and Efficient Reagent for the Preparation of Cyclic Acetals, Dithioacetals, and Benzodioxepins.

The influence of steric and electronic effects on the preparation of cyclic acetals catalyzed by sulfated metal oxides

Sulfated metal oxides (SMO) were able to catalyze the reaction of carbonyl compounds with ethylene glycol (EG), producing cyclic acetals at near ambient temperature. Sulfated hafnium oxide containing only Lewis acid sites (indicated by IR/pyridine adsorption experiments) was found active for the reaction. However, these Lewis acid sites might not be the active sites for the reaction, because they were most likely transformed into Bronsted acid sites by water produced in the reaction. Both electronic and steric effects played important roles in this reaction. The sulfate group coordinating to the active acid site had exerted a steric influence on the reaction. Therefore, the less bulky cyclic acetals were more readily formed. The carbonyl group conjugated with a double bond delocalized the positive charge on the carbocation reaction intermediate, resulting in lower cyclic acetal yields.