Synthesis of new heterocycles 1,3,2,6‐dioxaphosphaselenacyclooctanes

Abstract

AhrtrectNew phosphorus-and selenium-containing heterocyclyes, 1,3,2,6dioxaphosphaselena-cy~iooctanca (la--lb), were synthesized by the reaction of bis(2-hydmxyethyl)~elenide with RP(X)C12 where R=alkoxyl, aroxyl, aryl and X=O or lone pair. Their structures were determined by spectroscopia, and elemental analyses and finally confirmed by the X-ray crystallographic analysis of lc. The molecular structures of the hetetocyclca w e n discussed in term of conformational analysis. KeywordsHeterocycles, synthesis, structureMacrocycles possessing phosphorus have been synthesized as various and some complexes of them have been obtained. The importance of these molecules as phosphorus analogues of crown ethers, their potential catalytic activity and ion-carrier properties make their development desirable. Selenium atom is soft base, so it has high affinities for transition metal and heavy metal ions. The design of phosphorus heterocycles incorporating selenium may give rise to new powerful complexing agents. F' urthermore, organophosphorus compounds have preferential toxicity for cancer cells when released in tissues,' and organoselenium compounds have strong biological activities.6These prompted us to carry out the studies of P-Se heterocyclic compounds 1,3,2,6-dioxaphosphaselenacyclooctanes (1). Results and discussionThe 2-R-2-oxide-1,3,2,6dioxaphosphaselenacyclooct~es (R=ethoxy, la; R=phen-oxy, Ib; R=Cmethylphenoxy, lc; R=3,5-dimethylphenoxy, Id; R=2,Gdimethylphenoxy, le; R=phenyl, If) were prepared (shown as Scheme 1) by the reactions of bis(2-hydrcxxyethy1)selenide with ethyl or aryl phosphorodichloridate in the presence of pyridine as solvent and acid acceptor. The reactions were completed after 20 hours at room temperature as determined by the disappearance of bis( 2-hydroxyethy1)selenideO k e i v e

Synthesis, Characterization, and Combustion Catalytic Activities of Copper(II) and Lead(II) Salts of p‐Nitrocalix[n]arenes (n=4, 6, 8)

“…In addition, the amount of fuming nitric acid consumption in the nitration reaction owing to its unfriendly nature to the environment and human health was monitored. It was found that the optimal molar ratio for a p ‐ tert ‐butylcalix[ n ]arene ( n =4, 6, 8) to fuming nitric acid is about 1 : 100 (1 : 200 was used in Kumar’s description), but the reaction time should be extended from 5 h used in Kumar’s work to 8 h. Thus, the amount of fuming nitric acid used in this work is only half of that used in the literature 15a. All six metal salts were prepared in high yield and purity by mixing p ‐nitrocalixarenes with a copper or lead nitrate with a slight excess of the metal salt.…”