title: Calix[4]arene derivatives monosubstituted at all four methylene bridges.
abstract: The scope of the reaction of the tetrabromocalixarene derivative 2b with alcohols under solvolytic conditions in trifluoroethanol (TFE) or hexafluoroisopropanol (HFIP) was explored. The reaction proceeded readily with MeOH, EtOH, n-PrOH, ethylene glycol and i-PrOH affording preferentially the rccc isomer of the tetrasubstituted product. The methoxy derivative 6a undergoes isomerization upon attempted recrystallization from CHCl3/MeOH and its rcct and rctt forms were characterized by X-ray crystallography. Incorporation of hydroxy groups on the bridges was accomplished via solvolysis in AcOH, followed by LiAlH4 reduction of the acetoxy groups. Reaction of the tetra-(2-methylfuranyl)calixarene derivative 11 with benzyne followed by deoxygenation with Me3SiCl/NaI afforded in low yield the tetra-(4-methylnaphthyl)calix[4]arene derivative 12. Reaction of de-tert-butylated tetrabromo derivative 2a with m-xylene in HFIP followed by methylation of the crude product afforded the tetraxylyl derivative 14.
authors.affiliation: Department of Organic Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel. ishayc@iibr.gov.il
authors.forename: Ishay
authors.initials: I
authors.lastname: Columbus
authors.forename: Silvio E
authors.initials: SE
authors.lastname: Biali
mesh_terms: D000438:Alcohols / Q000737:chemistry; D047250:Calixarenes / Q000138:chemical synthesis* / Q000737:chemistry; D018360:Crystallography, X-Ray; D008697:Methane / Q000031:analogs & derivatives* / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D010636:Phenols / Q000138:chemical synthesis* / Q000737:chemistry; D020005:Propanols / Q000737:chemistry; D013237:Stereoisomerism; D014270:Trifluoroethanol / Q000737:chemistry; D006845:Hydrocarbons, Fluorinated
chemical_list: D000438:Alcohols; D047250:Calixarenes; D008697:Methane; D010636:Phenols; D020005:Propanols; D014270:Trifluoroethanol; C121325:calix(4)arene; C030011:carbene; C001337:hexafluoroisopropanol; D006845:Hydrocarbons, Fluorinated