The simultaneous determination of vitamin D2 and its isomers by high-speed liquid chromatography (HSLC) is described. Preferred operating conditions for the resolution and quantitation of vitamin D2 5,6-trans-vitamin D2, ergosterol, lumisterol2, isovitamin D2, isotachysterol2, tachysterol2, and previtamin D2 are as follows: column, "Zorbax" SIL (25 cm x 2.1 mm i.d.); pressure, 100-120 kg/cm2; t...

In this chapter, a comprehensive review over the entire reserarch on liquid crystalline crown ethers since their discovery will be given. Monomeric and polymeric molecules containing crown ethers as well as aza crown ethers, thia crown ethers and crown ethers with several different heteroatoms will be presented. Liquid crystallinity is, in most cases, caused by the substituents attached to the ...

a novel potentiometric ion-selective pvc membrane sensor for analysis of atorvastatin (at) in pharmaceutical preparations based on atorvastatin-(tetraphenyl borate), (at-(tpb)2) as sensing element, tetraphenyl borate as additive and tris-2-ethyl-hexyl phosphate (top) as plasticizer solvent was prepared. the electrode shows a good nernestian response over the concentration range of 0.09–5586 µg ...

Crown-ethers have recently been used to assemble porous liquids (PLs), which are liquids with permanent porosity formed by mixing bulky solvent molecules (e.g., 15-crown-5 ether) with solvent-inaccessible organic cages. PLs and crown-ethers belong to a novel class of materials, which can potentially be used for gas separation and storage, but their performance for this purpose needs to be asses...

This paper presents the ability of a new group contribution equation of state in the prediction of thermodynamic properties of alcohols, ketones and ethers. This equation of state, called MCORGC, is based on the Chain-Of-Rotators Group Contribution equation considering a NRTL type local composition mixing rule. The group parameters required to predict the thermodynamic properties of the oxygena...

The structural features of chloromethyl ethers are shown to have a significant effect on the formation of N(7)- or N(9)- alkylated isomers of purine acyclo-nucleosides. The chemical synthesis of 2-[9-(ethoxymethyl) adenyl] phosphonate is described. This compound is active against herpesviruses.

In a heretofore-unreported reaction, 1,2-cyclohexandione reacts with a variety of alcohols under mild acid-catalyzed dehydration conditions to afford not only ethers of 1,2cyclohexanedione but the corresponding aryl ethers as well in moderate to good yield.

We describe the first synthesis of homoallyl ethers from acetals and allyltrimethylsilane using microwave heating and CuBr as a promoter. This method works best for aromatic acetals, giving the corresponding homoallyl ethers in good to quantitative yield.