Microwave-assisted synthesis of 2-styryl-1,3,4-oxadiazoles from cinnamic acid hydrazide and triethyl orthoesters

Acid Hydrazides, Potent Reagents for Synthesis of Oxygen-, Nitrogen-, and/or Sulfur-Containing Heterocyclic Rings

“…This green protocol was catalyzed efficiently by solid supported NafionNR50 to have excellent yields (80–90%). A novel and efficient synthesis of 2-styryl-1,3,4-oxadiazoles (yields 95–98%) by cyclocondensation of cinnamic acid hydrazide and triethyl orthoesters under microwave irradiation is also reported by Kudelko and co-workers …”

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

“…Kudelko and Zieliǹski [ 49 ] developed an easy and efficient method to synthesize 5-substituted-2-styryl-1,3,4-oxadiazoles 85 from cinnamic acid hydrazide 83 and commercially available triethyl orthoesters 84 . The method provides the desired products rapidly and in high yields making it a useful addition to the existing synthetic procedures ( Scheme 31 ).…”

Current Parallel Solid-Phase Synthesis of Drug-like Oxadiazole and Thiadiazole Derivatives for Combinatorial Chemistry

“…The general 1,3,4-oxadiazole solution synthesis methods reported in the literature can be classified into four categories: (i) dehydrative cyclization of semicarbazides using dehydrating agents such as POCl 3 , SOCl 2 , concentrated H 2 SO 4 , the Burgess reagent, Appel conditions, and phosphonium reagents (Scheme , routes a , c , and d ); (ii) oxidative desulfurization of thiosemicarbazides using I 2 /NaOH, p -tosyl chloride ( p -TsCl), methyl iodide, ethyl bromoacetate, carbodiimides, mercuric salt, and lead oxide (Scheme , route b ); (iii) Huisgen reactions of tetrazoles and acid chlorides (Scheme , route e ); and (iv) one pot procedures involving compounds bearing nitrogen atoms (i.e., hydrazides) and another reagent that constitutes the 5-substituent source such as CS 2 , carboxylic acids, and isothiocyanates (Scheme , route f ). ,,,− …”