Synthesis of Calix[4]arenes with Dendritic Fragments

Dendrimer5arethree-dimensional,highorderedoligomericandPOlymericcomPOundS,whicharemo1ecular-1evelcontrolofsize,shapes,surfacechentistry,toPOlogyandflexibility.'.'Calixarenesarecyclicoligomers,whichhavebeenextensive1ystudiedinordertoobtalnnewhostsbyappropriatefiJnctionalizationoftheparentmolecule.3,#Besides,calixarenesareattractivecandidatesfOrpolponctionalcoresindendriticmolecules,esPeciallybytheconvergentgroWthaPProach.'ltisinterestingthatthemoleculeofcombinationofcalixarenewithdendritic…     

Solid‐Phase One Step Synthesis of 4H,4′‐Exomethylene‐bis[quinazolin‐2‐enols]

Abstract

The solid‐phase one step synthesis of 4H,4′‐exomethylene‐bis[quinazolin‐2‐enols] via 1,3‐dipolar cycloaddition of urea on benzylideneacetophenone using Sb(III) chloride impregnated alumina is described. The reaction provides 80–85% dimeric quniazolinenols. The process is convenient, cost‐effective and eco‐friendly.     

Synthesis of Pyridylazo-substituted Chromogenic Calix[4]arenes

Calixarenes are a versatile class of macrocyclic compounds which have attracted extensive interest due to their ability to form host-guest complexes and act as enzyme mimic, especially when appropriately functionalized1. Introduction of azo group to calixarenes can make the later to be easily detected in the process of molecular recognition, azo groups have been introduced into calixarenes by the diazo-coupling reaction of calix[4]arene with BF4- or chloride salt of substituted benzene diazon…     

Synthesis and properties of p-per fluoroalkylcalix [4]arenes

p-Perfluoroalkylealix[4]arenes were prepared readily from the reaction of calix-[4]arene with perfluoroalkyl iodides in the presence of sodium dithionite or sodium hydroxy-methanesulfinate under mild conditions,These fluorine-containing calixarenes showed bettersolubilities in common organic solvents as compared to their nonperfluoroalkylation analogand formed inclusion complexes with many neutral molecules as well as fluorocarbons.     

Synthesis of （p-Formylphenyl）azo Calix[4]arenes

Five novel azo calix[4]arenes were reported. The p-aminobenzaldehyde was diazotized with sodium nitrite in aqueous hydrochloride solution. Mono-, bis-, tris- and tetrakis(p-formylphenyl)azo calix[4]arenes (including proximal and distal isomers) were obtained respectively by diazo-coupling in different molar ratio to calix[4]arene(1) under pH=7.5--8.5 at 0-5℃. All (p-formylphenyl)azo calix[4]arenes were characterized by ^1H NMR, ^13C NMR, IR, MS (ESIMS) spectroscopies and elemental analysis.     

One‐Step Synthesis of 2‐Aminothiazoline Derivatives Free of Lachrymatory Intermediates

A convenient one‐step condensation of p‐R‐acetophenones, dioxane dibromide, and N,N′ dialkylthioureas was developed as a synthetic access to derivatives of 2‐amino‐1,3‐thiazoline, such as N‐[4‐(4‐R‐phenyl)‐3‐R1‐2,3‐dihydro‐1,3‐thiazol‐2‐yliden]‐N‐(R1)amine, where R=H, Br, NO₂, or CH₃O, and R1=CH₃, CH₃CH₂, CH₃CH₂CH₂CH₂, or Ph. Unlike the routine syntheses of similar compounds based on lachrymatory ω‐halogenated acetophenones, the one‐step approach escapes the preparation and dealing with inconvenient starting materials. The yields based on the starting p‐R‐acetophenones were in the range of 57–70%.     

Synthesis and characterization of a novel series of pyrimidinylthiaalkoxycalix[4]arenes

A novel series of pyrimidinylthiaalkoxycalix[4]arenes with the reaction between 4,6-dimethylpyrimidine-2-thiol and thedifferent dibromides calix[4]aryl groups have been synthesized and structurally characterized by IR,1H NMR and MS.From theiranalysis data,it was found that compounds 8,9,11 adopted a cone conformation,while compound 10 existed as a mixture ofconformations.     

High Stereoselective Glycosylation of Calix[4]arenes with α-Acetobromoglucopyranoside

Ithasbeenevidencedthatcthehydratesp1ayamajorroleinnature,etwallyasrecoghtiondeterminantsuchasinh0st-pathogeninteractionsorincell-cellintendions.Moreover,dramaticchangesinthestruct-Uresofcarbohydratemoiety0fglycocojugaesoftenareassociatedwithcogeniceventsWhichaIlowtousesomeofthemastumormarkersusefu1f0rdiagnosticpurp0ses.'Inordertobetterundersbodtheseinteractionandtodeve1opbio1ogicalaCtivecomPOundsbased0nm0lecularrecoghtion,stereoc0ntrolledgJycoSylationhasbecome0neofthemostimPOrtanttopicinor…     

One‐Step Synthesis of 2‐Aryl‐4,5‐diphenylimidazoles Under Microwave Irradiation

Abstract

A series of 2‐aryl‐4,5‐diphenylimidazoles were synthesized by a one‐step condensation reaction of benzil, aromatic aldehyde, and ammonium acetate in acetic acid under microwave irradiation. The reactions were completed in 4–11 min with good yields and easy workup.     

Microwave‐Assisted One‐Step Synthesis of Substituted 2‐Chloromethyl‐1,3,4‐oxadiazoles

Abstract

We have developed a simple one‐step synthesis of 2‐chloromethyl‐1,3,4‐oxadiazoles from commercially available acylhydrazides using 1‐chloro‐2,2,2‐trimethoxyethane as a solvent under microwave irradiation.     

One‐Step Synthesis of Tolunitriles by Heterogeneously Catalyzed Liquid‐Phase Ammoxidation

Tolunitriles have been efficiently synthesized by selective ammoxidation of corresponding xylene over silica‐supported Co‐Mn‐Mg‐Ni catalysts, without solvent for the first time in a one‐pot procedure. The selectivity for mono‐nitriles is almost 100%.     

Synthesis and structure characterization of a novel series of N-alkylphthalimidylaminocarbonylmethoxylcalix [4] arenes

A novel series of N-alkylphthalimidylaminocarbonylmethoxylcalix[4]arenes with the reaction between 4-(N-bromoacetyla- mino)-phthalimide derivatives and calix[4]arene has been synthesized and structurally characterized by IR,~1HNMR and MS.From their analysis data,it was found that compounds 7a-7d adopted a cone conformation.     

Upper Rim Diester—bridged Calix[4] arenes and Oligocalix [4]—arenes：the Effects of the Length of Bridged Reagents on Their Distribution

A series of monobridged calix [4] arenes 3a-f,cyclic biscalix-[4] arenes 4a-f ,diametrically bridged at the upper rim with saturated aliphatic diester chians,have been synthesized,The results at diluted conditions show that the percentage of yields of mono-,bis- and oligo-calix[4] arenes are related to the legth of the chains ,With the shortening of the chains ,the percent-age of monocalix[4] arenes decreased ,All the calix [4] arene moieties are in a cone conformaiton according to the AB quar-tet pattern of the methylene protons between the phenolic rings in the ^1H NMR spectra.     

Novel Synthesis and Characterization of 1,3‐Bis(2‐dihydrothiazolyl)thiaalkoxy‐p‐tert‐butylcalix[4]arenes

A novel series of 1,3‐bis(2‐dihydrothiazolyl)thiaalkoxy‐p‐tert‐butylcalix[4]arenes generated by the reaction between 4,5‐dihydrothiazole‐2‐thiol and the different dibromide calix[4]aryl groups have been synthesized and structurally characterized by IR, ¹H NMR, ¹³C NMR, and MS. From their analytical data, it was found that compounds 8, 9, and 10 had cone conformations, whereas compound 11 existed as a mixture conformation. To verify the structure of the synthetic compounds, a single‐crystal X‐ray structure of compound 8 was obtained.     

Novel Synthesis of p‐t‐Butylcalix[n]arenes Bearing Ethylene Glycol Ether Chains

Abstract

An approach for the synthesis of calixarene derivatives 3a–d, which contain ethylene glycol ether units at the lower rim in moderate yields, is described. The above compounds have been achieved by treating p‐Butylcalix[n]arenes 1a–b (n = 6, 8) with chloroacetate 2a–b of 2‐methoxyethanol and 2‐(2‐butoxyethoxy)ethanol in the system of K₂CO₃/KI/acetone.     

KF‐Alumina Catalyzed One‐Pot Synthesis of Pyrido[2,3‐d]Pyrimidine Derivatives

Abstract

A series of pyrido[2,3‐d]pyrimidine derivatives was synthesized by the reaction of arylaldehyde, malononitrile, and 4‐amino‐2,6‐dihydroxylpyrimidine in ethyl alcohol at 80°C catalyzed by KF‐Al₂O₃. Compared with other synthetic methods, this new method has the advantage of easier workup, milder reaction conditions, and good yields.     

One‐Pot,High‐Yielding Synthesis of Novel Dihydrothiazolo[3,2‐a]pyrimidinones

Reaction between 6‐(un)substituted‐2‐thiouracils and E‐ethyl 4‐bromocrotonate under basic conditions at room temperature is an easy, mild, high‐yielding, and regioselective method for the preparation of 7‐(un)substituted dihydrothiazolo[3,2‐a]pyrimidinone derivatives.     

Synthesis of （p—Substituted phenyl）azo Calix[4] arenes

A novel method for the preparation of chromogenic calixarenes with azo groups was reported.p-Substituted(-NO2,-CH3,-Cl)amilines were diazotized with isoamyl nitrite in EtONa/EtOH under refluxing condition.Fifteen mono-,bis-,tris-and tetrakis(p-substituted phenyl)azo calix[4]arenes (including proximal and distal isomers) were obtainged respectively by diazo-coupling in different molar ratio to calix[4]arenes(1) under pH=7.5-9.0 in non-aqueous solution at 0-5℃.^1H NMR and ^13C NMR spectra of (p-substtituted phenyl)azo calix[4]-arenes indicated that they existed in cone conformation in solution.     

One‐Pot Synthesis of Trifluoromethylated 4‐Cyanoalka‐1,4‐dienes with Predominant Z‐Selectivity

The consecutive reaction of diethyl (1‐cyanobut‐3‐enyl)phosphonate with n‐butyllithium, trifluoroacetic anhydride, and Grignard reagents gave trifluoromethylated 4‐cyano‐alka‐1,4‐dienes in 45–89% yields with predominant Z‐selectivity (Z∶E=89–78∶11∶22). Two isomers could be easily separated by column chromatography.     

Synthesis and Characterization of Picolinamide Calix[6]arenes Derivatives

It is well known that calixarenes are extremely versatile classes of macrocyclic receptor able to complex various metal ions as well as to selectively recognize both neutral and charged inorganic or organic species in solution. It is unable to get a clear…