Synthesis and Characterization of a Series of 1-Aryl-4-[aryldiazenyl]- piperazines. Part I. Isomers of N-(2,3-Dimethylphenyl)-N’-(Aryldiazenyl)- Piperazines

Chenguang Fan,Keith Vaughan

doi:10.2174/1874842201502010020

Abstract

This paper describes the synthesis of several new series of 1-(2-aryldiazen-1-yl-) 4-arylpiperazines and 1-(2- aryldiazen-1-yl-)4-arylalkylpiperazines by using diazonium coupling between arenediazonium ions with the appropriate 1-arylpiperazine or the 1-arylalkylpiperazine. The new compounds have a common thread in that they are isomers of the series of N-(2,3-dimethylphenyl)- N’-(aryldiazenyl)-piperazines. The new triazenes have been characterized by IR and NMR spectroscopy and mass spectrometry.

Highlights

Previous work in this laboratory has described the synthesis of the 1,4-bis-(2-aryl-diazen-1-yl-)piperazines (1)[1, 2] using the bis-diazonium coupling reaction with piperazine itself (equation (i)): In a similar fashion, diazonium coupling with 1methylpiperazine afforded a series of 1-(2-aryldiazen-1-yl)4-methylpiperazines (2a) [3](equation ii): the N-aryldiazenylpiperazines is to investigate the synthesis of the1-aryl-4-[aryldiazenyl] -piperazines (2d) by diazonium salt coupling with a series of 1-arylpiperazines
A series of N-(2,3-dimethylphenyl)N’-(aryl-diazenyl)-piperazines (3) have been synthesized by diazonium coupling with N-(2,3-dimethylphenyl-)piperazine. These new triazenes represent the first ever piperazine derivatives to be reported with one N-aryl substituent at N4 opposite to the N-aryldiazenyl substituent at N1
The common thread of all the new compounds reported in this paper is that they are isomers of the compounds of series 3

Summary

Introduction

Previous work in this laboratory has described the synthesis of the 1,4-bis-(2-aryl-diazen-1-yl-)piperazines (1)[1, 2] using the bis-diazonium coupling reaction with piperazine itself (equation (i)): In a similar fashion, diazonium coupling with 1methylpiperazine afforded a series of 1-(2-aryldiazen-1-yl)4-methylpiperazines (2a) [3](equation ii): the N-aryldiazenylpiperazines is to investigate the synthesis of the1-aryl-4-[aryldiazenyl] -piperazines (2d) by diazonium salt coupling with a series of 1-arylpiperazines. A series of N-(2,3-dimethylphenyl)N’-(aryl-diazenyl)-piperazines (3) have been synthesized by diazonium coupling with N-(2,3-dimethylphenyl-)piperazine. These new triazenes represent the first ever piperazine derivatives to be reported with one N-aryl substituent at N4 opposite to the N-aryldiazenyl substituent at N1. Further investigation led to the synthesis of a large number of 1-(2-aryldiazen-1-yl-)4-acylpiperazines (2c); the paper describing these latter results has recently been published [5]. The logical step in the pursuit of new molecules of Isomeric compounds described as 1-(methylphenylmethyl)-4-(aryldiazenyl)-piperazines (4 , 5 and 6) have been prepared and characterized: 1874-8422/15 2015 Bentham Open

Methods

Results

Conclusion