Fragmentation and skeletal rearrangements of 2-arylylamino-5-aryl-1,3,4-oxadiazoles and their noncovalent complexes with cobalt cation and cyclodextrin studied by mass spectrometry
studied by electron ionization (EI) and electrospray ionization (ESI) as methods of ion generation. To explain the observed complex skeletalrearrangements, tandem mass spectrometry, accurate mass measurement and isotope labeling (compounds containing one 13C atom in oxadiazole ring) were used. Loss of CO, N2 and H atoms under EI conditions led to the formation of 9,10-dihydroacridine-type ions, loss of
An efficient method for the synthesis of 2,5-disubstituted1,3,4-oxadiazolesfrom isothiocyanates and hydrazides through cyclodesulfurization in the presence of (O-(benzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium tetrafluoroborate) TBTU as an uronium coupling reagent has been developed. The present methodology offers several advantages, such as simple and easy work-up procedures, mild reaction conditions
Prabhu, Girish; Madhu, Chilakapathi; Sureshbabu, Vommina V., Indian Journal of Chemistry - Section B Organic and Medicinal Chemistry, 2014, vol. 53, # 7, p. 865 - 870
作者:Prabhu, Girish、Madhu, Chilakapathi、Sureshbabu, Vommina V.
DOI:——
日期:——
Synthesis of 2-amino-1,3,4-oxadiazoles from isoselenocyanates via cyclodeselenization
作者:Yuanyuan Xie、Junli Liu、Ping Yang、Xiangjun Shi、Jianjun Li
DOI:10.1016/j.tet.2011.05.100
日期:2011.7
An efficient one-pot method to access 2-amino-1,3,4-oxadiazoles from isoselenocyanates and hydrazides or dihydrazides was developed via cyclodeselenization. Without any harsh reagents, various 2-amino-1,3,4-oxadiazoles were obtained in considerably high yields (82%-97%) and purities (>99%) directly with simple crystallization in ethanol. And the formed precipitated Se powder during the reaction could be recycled for preparation of isoselenocyanates efficiently. A plausible mechanism is proposed for the formation of the target products. (C) 2011 Elsevier Ltd. All rights reserved.