Microwave-Assisted Solution Phase Synthesis of Novel 2-{4-[2-(N-Methyl-2-pyridylamino)ethoxy]phenyl}-5-Substituted 1,3,4-Oxadiazole  Library

Abstract

A new series of 2-{4-[2-(N-methyl-2-pyridylamino)ethoxy]phenyl}-5-substituted 1,3,4-oxadiazoles were synthesized by the oxidative cyclization of hydrazones derived from 4-[2-(methylpyridin-2-ylamino)ethoxy]benzaldehyde and aryl hydrazines using chloramine-T as an efficient catalyst. All steps were assisted by microwave irradiation. Microwave enables all these reactions to be simple, rapid, high yielding, and avoid chromatograph purification and led environmentally benign total synthesis of focused oxadiazole library. All the synthesized compounds were isolated in good yield and characterized by 1 H NMR, 13 C NMR, and elemental analyses. The title compounds represent a novel class of biologically active heterocycles.

Synthetic Approaches and Pharmacological Activity of 1,3,4-Oxadiazoles: A Review of the Literature from 2000–2012

“…Li and He [ 43 ] synthetized the compound 2-(anthracen-9-yl)-5-(p-tolyl)-1,3,4-oxadiazole ( 72 ) in 75.4% yield from oxidative cyclization of N -acylhydrazone 71 using chloramine-T, (Entry a , Scheme 26 ). Gaonkar and co-workers [ 44 ] also reported the synthesis of 1,3,4-disubstituted oxadiazoles 74 from the oxidative cyclization of N -acylhydrazones 73 with chloramine-T under microwave irradiation, (Entry b , Scheme 26 ).…”

Microwave-Assisted Synthesis of Five-MemberedO,N,N-Heterocycles

“…Though there are several reagents for cycloaddition, chloramine-T is found to be an effective reagent because it is mild, easy to handle, commercially available, nontoxic, and water tolerant. [34] Baxendale and coworkers [35] developed a methodology for the preparation of 5-substituted-2-amino-1,3,4-oxadiazoles and their 2-aminosulfonylated analogs by using strong bases such as polystyryl-BEMP (PS-BEMP) and TsCl. [36] They catalyzed both cyclodehydration and subsequent sulfonamidation.…”

Design, Synthesis, Antimicrobial Evaluation, and Laccase Catalysis Effect of Novel Benzofuran–Oxadiazole and Benzofuran–Triazole Hybrids

“…Studies have revealed that compounds having oxadiazole ring, especially 1,3,4‐oxadiazole, are interesting structural cores, which can exhibit excess of unique biological activities such as antibacterial , analgesic , antiviral , antitubercular , and muscle relaxant activities .…”