Reactions of organotin tetrazoles: synthesis of functionalised poly-tetrazoles

Reaction of 1,2-bis[2-(tributylstannyl)tetrazol-5-yl]benzene with 1,2-dibro moethane (1:10) yields the 1- N,1-N'-ethylene bridged cyclophane (1) while similar reactions with larger excesses (1:25) of 1,n- dibromoalkanes yield 1,2-bis[2-(bromoalkyl)tetrazol-5-yl]benzenes along with the unsymmetrical 1 -N,2- N-substituted tetrazole isomers. Analogous products from 1,3-(Bu3SnN4 C)(2)C6H4 are also reported. Similar reactions occur between the two organo tin compounds and 1-bromo-n-cyanoalkanes to give 1,m-bis[(cyanoalkyl)tetraz ol-5 yl]benzenes (m = 2, 3) as both symmetric and unsymmetrically substitut ed tetrazole isomers, and which can be further developed to convert the pen dant nitriles into tetrazoles by cycloaddition reactions with Bu3SnN3. The Bu3Sn group is easily cleaved by H+ to generate the related N-unsubstituted tetrazoles.