24759-97-5Relevant articles and documents
Synthesis of Non-symmetrical Dispiro-1,2,4,5-Tetraoxanes and Dispiro-1,2,4-Trioxanes Catalyzed by Silica Sulfuric Acid
Amado, Patrícia S. M.,Coelho, Jaime A. S.,Cristiano, Maria L. S.,Frija, Luís M. T.,O'neill, Paul M.
, p. 10608 - 10620 (2021/07/31)
A novel protocol for the preparation of non-symmetrical 1,2,4,5-tetraoxanes and 1,2,4-trioxanes, promoted by the heterogeneous silica sulfuric acid (SSA) catalyst, is reported. Different ketones react under mild conditions with gem-dihydroperoxides or peroxysilyl alcohols/β-hydroperoxy alcohols to generate the corresponding endoperoxides in good yields. Our mechanistic proposal, assisted by molecular orbital calculations, at the ωB97XD/def2-TZVPP/PCM(DCM)//B3LYP/6-31G(d) level of theory, enhances the role of SSA in the cyclocondensation step. This novel procedure differs from previously reported methods by using readily available and inexpensive reagents, with recyclable properties, thereby establishing a valid alternative approach for the synthesis of new biologically active endoperoxides.
Two-step synthesis of achiral dispiro-1,2,4,5-tetraoxanes with outstanding antimalarial activity, low toxicity, and high-stability profiles
Ellis, Gemma L.,Amewu, Richard,Sabbani, Sunil,Stocks, Paul A.,Shone, Alison,Stanford, Deborah,Gibbons, Peter,Davies, Jill,Vivas, Livia,Charnaud, Sarah,Bongard, Emily,Hall, Charlotte,Rimmer, Karen,Lozanom, Sonia,Jesús, María,Gargallo, Domingo,Ward, Stephen A.,O'Neill, Paul M.
, p. 2170 - 2177 (2008/12/21)
A rapid, two-step synthesis of a range of dispiro-1,2,4,5-tetraoxanes with potent antimalarial activity both in vitro and in vivo has been achieved. These 1,2,4,5-tetraoxanes have been proven to be superior to 1,2,4-trioxolanes in terms of stability and to be superior to trioxane analogues in terms of both stability and activity. Selected analogues have in vitro nanomolar antimalarial activity and good oral activity and are nontoxic in screens for both cytotoxicity and genotoxicity. The synthesis of a fluorescent 7-nitrobenza-2-oxa-1,3-diazole (NBD) tagged tetraoxane probe and use of laser scanning confocal microscopy techniques have shown that tagged molecules accumulate selectively only in parasite infected erythrocytes and that intraparasitic formation of adducts could be inhibited by co-incubation with the iron chelator desferrioxamine (DFO).
Sulfur ylides in reactions with 5-X-adamantan-2-ones. Stereochemistry and reactivity
Catanoso, Giada,Di Credico, Barbara,Vecchi, Elisabetta
, p. 2151 - 2160 (2007/10/03)
This work describes the stereochemistry and the relative rates of epoxidation reactions of the title compounds with sulfur ylides (methylenedimethylsulfurane and methylenedimethyloxysulfurane) in DMSO and C6H6. The electronic perturbative effect of substituent X depends on the solvent and on the reactant. It is transmitted in opposite way in solvents of different polarity depending on the reactant. The electronegativity of the substituent scarcely affects the percentages of axial/equatorial attack. The percentage of equatorial attack with methylenedimethyloxysulfurane is markedly lower for 5-X-adamantan-2-ones than for 4-X-cyclohexanones.
