Microwave-assisted synthesis of calix[4]resorcinarenes

Recent developments in use of heteropolyacids, their salts and polyoxometalates in organic synthesis

“…Excellent isolated yields (up to 90%) were attained within short reaction times (typically, 3-5 min) when the reaction was performed under microwaves irradiation (Scheme 25) [73].…”

Synthesis, spectral characterization of azo dyes derived from calix[4]resorcinarene and their application in dyeing of fibers

“…Calix [4]resorcinarenes [1] are analogs of calixarene having two hydroxy groups on benzene rings at extra annular position forming a macrocycle. Calix [4]resorcinarenes are synthesized by the acid-catalyzed cyclocondensation of resorcinol with various aliphatic or aromatic aldehydes [2][3][4][5].…”

“…Calix [4]resorcinarenes are synthesized by the acid-catalyzed cyclocondensation of resorcinol with various aliphatic or aromatic aldehydes [2][3][4][5]. They have found application as macrocyclic receptor [6], as dendrimers in biological systems [7][8][9], nano-capsule [10], nanoparticales [11,12], opticalchemosensors [13], supramolecular tectons [14][15][16], host molecules [17,18], as components in liquid crystals [19,20], photo resists [21][22][23], selective membranes [24,25], surface reforming agents [26], HPLC stationary phase [27], as ion channel mimics [28], and metal ion extraction agents [29][30][31].…”

“…It has been known for many years that azo compounds are most widely used class of dyes due to their versatile application in various fields such as the dyeing of textile fiber, the coloring of different materials, colored plastics, biological-medical studies and advanced application in organic synthesis [32][33][34][35]. There have been few reports wherein macrocycles such as crown ethers [36] and calixarenes [37][38][39][40] have been used as components for the preparation of azo dyes but the research in the area of azocalix [4]resorcinarene dyes [41] is still in infancy.…”

“…In the present work we are reporting seven new supramolecular chromogenic azo dyes derived from coupling of diazonium salt of p-chloroaniline, p-nitroaniline, ptoludine, p-anisidine, p-aminobenzoic acid, o-aminophenol, and aniline with calix [4]resorcinarene, bearing -N=N-group as well as -OH group to enable it to exhibit both coloring and binding properties. Effect of solvents of varying dielectric constants on the absorption spectra of substituted and unsubstituted azocalix [4]resorcinarene have been studied by UV-vis spectrophotometer.…”