P. Narayana, N. Seelam, B. Prasanna
Nov 2, 2018
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Journal
Organic Preparations and Procedures International
Abstract
We now describe a facile synthesis of 1,4-bis((1,4,8,11-tetraazacyclotetradecan-1-yl)methyl)benzene octahydrochloride 3 from 1, 4, 8, 11-tetrazacyclotetradecane 1 with dibromo-p-xylene 2 under phase transfer catalysis. The method gives good yields without protection and deprotection. The chemistry of the tetraazacycloalkanes has undergone considerable development in the last years. Among their other properties, these macrocyclic polyamines are able to form stable complexes with transition metals, lanthanides, actinides, and other heavy metals. The affinity and selectivity towards the metal ion can be tuned by varying the size of the macrocyclic core as well as the nature and the number of pendant coordinating arms on the nitrogen atoms. In addition, these molecules exhibit numerous biomedical applications. These were described as a new class of antiviral agents with potent inhibitory effects on HIV-1 and HIV-2 replication, along with high selectivity. Many methods have been devised for the synthesis of tetrazocyclodecanes and their functionalized derivatives, including high dilution techniques, use of metal cations as templates, protection/de-protection sequences and functionalization on either nitrogen or carbon atoms. A recent key step in this chemistry is the use of bis-aminal intermediates. 8–15 Our new method avoids protection/de-protection sequences and is shown in Scheme 1. Compound 3 was synthesized from 1 with dibromo-p-xylene 2 under phase transfer conditions, using tetra-n-butyl ammonium bromide (TBAB), in good yield. The spectral and analytical data strongly supported the structure of 3 (see Experimental