Intermolecular reactions phase-transfer catalysis

Compound 98 was condensed with o-aminothiophenol, 2-aminoethanol, or cystamine in refluxing diphenyl ether through an intermolecular cyclization with the elimination of two molecules of water to give the polyfused derivatives 101-103, respectively. Also, the reactions of 98 with dimethylthiomethylenemalononitrile in boiling dimethylforma-mide (DMF) were studied. The dimethylthiomethylenemalononitrile was prepared via the reaction of malononitrile with CS2 with 2 equiv of methyl iodide in a one-pot reaction using liquid-liquid phase-transfer catalysis (PTC) technique (NaOH/dioxane/tetrabutylammonium bromide (TBAB)). The product of this reaction was identified as 8-cyano-9-imino-7-methylthio-6-oxo-3-phenyl-5,6,8,9-tetrahydro-77/-pyrano[3,2-/][l,2,4]-triazolo[3,4-A][l,3,4]thia-diazepine 104 (Scheme 10). 

Many phenomena of interest in science and technology take place at the interface between a liquid and a second phase. Corrosion, the operation of solar cells, and the water splitting reaction are examples of chemical processes that take place at the liquid/solid interface. Electron transfer, ion transfer, and proton transfer reactions at the interface between two immiscible liquids are important for understanding processes such as ion extraction, " phase transfer catalysis, drug delivery, and ion channel dynamics in membrane biophysics. The study of reactions at the water liquid/vapor interface is of crucial importance in atmospheric chemistry. Understanding the behavior of solute molecules adsorbed at these interfaces and their reactivity is also of fundamental theoretical interest. The surface region is an inhomogeneous environment where the asymmetry in the intermolecular forces may produce unique behavior. 

---