The reaction of (N‐isocyanimino) triphenylphosphorane with (E)‐3‐aryl‐2‐ propenoic acid derivatives: One‐pot synthesis of 2‐[(E)‐2‐aryl‐1‐ethenyl]‐1,3,4‐oxadiazoles via intramolecular aza‐Wittig reaction

Abstract

The reaction of (E)‐3‐aryl‐2‐propenoic acid derivatives with (N‐isocyanimino) triphenylphosphorane proceeds smoothly at room temperature to afford the corresponding 2‐[(E)‐2‐aryl‐1‐ethenyl]‐1,3,4‐oxadiazole via an intramolecular aza‐Wittig reaction in good yields under neutral conditions. The structures of the products were deduced from their IR, 1H NMR, and 13C NMR spectra and mass spectrometry. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 22:612–616, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20701

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

“…Ramazani and Rezaei [ 51 ] developed a novel and efficient method for the synthesis of 2,5-disubstituted-1,3,4-oxadiazoles 88 in high yield by a one-pot condensation procedure in CH 2 Cl 2 at room temperature involving four components: ( N -isocyanimino)triphenylphosphorane ( 87 ), a secondary amine, a carboxylic acid, and an aromatic aldehyde ( Scheme 33 ). For similar reactions with their respective mechanisms, see references [ 52 , 53 , 54 , 55 , 56 , 57 ].…”

One Reacts as Two: Applications of N-Isocyaniminotriphenylphosphorane in Diversity-Oriented Synthesis

“…Ramazani’s approach takes place at room temperature in good to excellent yields and relatively short reaction times. − The reaction proceeds smoothly in a variety of solvents and tolerates both electron-donating and electron-withdrawing groups in any substitution pattern of the aromatic ring ( 26a , d , and e ). Vinylic substrates proved to be good partners in this reaction as well, as Ahankar and co-workers subsequently demonstrated in 2011 . In this latter publication, a series of aryl-substituted cinnamic acid derivatives were reacted with NIITP to form 2-[( E )-2-aryl-1-ethenyl]-1,3,4-oxadiazoles 26f in good yields (76–83%).…”

“…Vinylic substrates proved to be good partners in this reaction as well, as Ahankar and co-workers subsequently demonstrated in 2011. 56 In this latter publication, a series of aryl-substituted cinnamic acid derivatives were reacted with NIITP to form 2-[(E)-2-aryl-1ethenyl]-1,3,4-oxadiazoles 26f in good yields (76−83%). Besides, the influence of sonication on the reaction of NIITP with substituted benzoic acids was tested by Ramazani's group.…”