Calix[4]arene based 1,3,4-oxadiazole and thiadiazole derivatives: Design, synthesis, and biological evaluation

Abstract

In the present investigation, we describe some novel calixarene based heterocyclic compounds (5a-5i) in which 1,3,4-oxadiazole and 1,3,4-thiadiazole derivatives have been coupled with 5,11,17,23-tetra-tert-butyl-25,27-bis(chlorocarbonyl-methoxy)-26,28-dihydroxy calix[4]arene. All the newly synthesized calixarene based heterocyclic compounds have been characterized by elemental analysis and various spectroscopic methods like FTIR, (1)H NMR, (13)C NMR, and FAB-MS. All the final scaffolds have been subjected to antioxidant activity, in vitro antimicrobial screening against two gram (+ve) bacteria (S. aureus, S. pyogenes), two gram (-ve) bacteria (E. coli, P. aeruginosa) and two fungal strains (C. albicans, A. clavatus) and also have been screened for their antitubercular activity against Mycobacterium tuberculosis H(37)Rv.

A new and efficient method for the synthesis of 2-N-(aryl)-1,3,4-oxadiazole-2,5-diamine derivatives

“…Heterocyclic compounds represent a huge family of biologically active organic molecules which have attracted the supreme attention of chemists throughout the world [1][2][3]. A majority of marketed drugs have included heterocyclic entities, highlighting their key roles in medicinal chemistry.…”

“…The outcomes of these particular reagents, including Burgess-type [10,11] reagents and phosphonium salts, in inflexible byproduct materialization, conversely, have generally been limited to usage in solidphase synthetic strategies. Recently, the Boger group [12,13] reported an exciting method to synthesize 2-amino- [1,3,4]-oxadiazoles via the dehydrative cyclisation of a semicarbazide substrates mediated by tosyl chloride and a base at conventional room temperature [14,15]. We have been paying attention to this methodology due to the low price of reagents and mild reaction conditions.…”

“…We have been paying attention to this methodology due to the low price of reagents and mild reaction conditions. Typically, 2,5-diamino- [1,3,4]oxadiazole derivatives are prepared by cyclization of the corresponding acyclic hydrazine-1,2-dicarboxamide substrates, semicarbazides and thiosemicarbazides [16]. We have a current interest in the development of novel strategies to access functionalized oxadiazoles.…”

“…We have a current interest in the development of novel strategies to access functionalized oxadiazoles. In an effort to chemically sew up these biologically active heterocycles, we sought to develop a synthesis of 2,5-diamino substituted- [1,3,4]-oxadiazoles as a major skeleton. Experimental charts for cyclisation reactions are shown in the supporting information, S1-S11, and are explained in the experimental section.…”

Calix[4]arene α-hydroxymethylphosphonic acids as potential inhibitors of protein tyrosine phosphatases

“…Because of their unique three-dimensional structure they have used as important tools for investigations in bioorganic chemistry and medicine [15][16][17][18]. The calixarenes were found to exhibit antibacterial activity against gram-positive and gramnegative bacterial strains [19][20][21], antiviral [22,23] and anticancer properties [24]. Finely, calixarenes can be used for biochemical recognition and separation of bioactive molecules such as amino acids, proteins, nucleotides, saccharides and steroids [25].…”