A novel annulation reaction of N-(het)aroyldiazenes and isothiocyanates has been established. This transformation involves a sequential cyclization and desulfurization/intramolecular rearrangement to produce 2-imino-1,3,4-oxadiazolines. The less-stable N-(het)aroyldiazenes can be conveniently generated in situ by I2-mediated oxidation of hydrazides, which allows a one-pot synthesis of the products
Synthesis of 2-Imino-1,3,4-thiadiazoles from Hydrazides and Isothiocyanates via Sequential Oxidation and P(NMe<sub>2</sub>)<sub>3</sub>-Mediated Annulation Reactions
N-acyldiazenes with isothiocyanates, producing 2-imino-1,3,4-thiadiazoles, is reported. This reaction proceeds well with crude N-acyldiazenes derived from the oxidation of hydrazides by iodine and permits the sequential synthesis of products directly from hydrazides without purification of the less stable N-acyldiazene intermediates. The reaction does not require transition metals and is a simple, scalable operation
Assembly of <i>N</i>,<i>N</i>-Disubstituted Hydrazines and 1-Aryl-1<i>H</i>-indazoles via Copper-Catalyzed Coupling Reactions
作者:Xiaodong Xiong、Yongwen Jiang、Dawei Ma
DOI:10.1021/ol300847v
日期:2012.5.18
CuI-catalyzed coupling of N-acyl-N′-substituted hydrazines with aryl iodides takes place at 60–90 °C to afford N-acyl-N′,N′-disubstituted hydrazines regioselectively and thereby gives a facile method for assembling N,N-diaryl hydrazines. N-Acyl-N′-substituted hydrazines can also react with 2-bromoarylcarbonylic compounds at 60–125 °C under the catalysis of CuI/4-hydroxy-l-proline to provide 1-aryl-1H-indazoles
Reagent/Substituent Switching Approach for the Synthesis of Substituted 1,3,4-Oxadiazole/1,3,4-Oxadiazoline and 1,2,4-Triazole Derivatives from N-Substituted Hydrazides
作者:Trimurtulu Kotipalli、Veerababurao Kavala、Ashok Konala、Donala Janreddy、Chu-Wei Kuo、Ching-Fa Yao
DOI:10.1002/adsc.201600274
日期:2016.8.18
A metal‐free method for the synthesis of substituted 1,3,4‐oxadiazole/1,3,4‐oxadiazoline and 1,2,4‐triazole derivatives from a common starting material via reagent/substituent switching is reported. In the presence of 2‐fluoropyridine/triflic anhydride, 1,3,4‐oxadiazole derivatives were exclusively formed from N′‐tert‐butylhydrazides and 1,3,4‐oxadiazoline derivatives were produced from N‐phenylhydrazides
Copper(<scp>ii</scp>)-catalyzed coupling reaction: an efficient and regioselective approach to N′,N′-diaryl acylhydrazines
作者:Ji-Quan Zhang、Gong-Bin Huang、Jiang Weng、Gui Lu、Albert S. C. Chan
DOI:10.1039/c4ob02343a
日期:——
An efficient and regioselective copper(ii)-catalyzed coupling reaction of N′-aryl acylhydrazines for the synthesis of N′,N′-diaryl acylhydrazines has been developed.