Synthesis and Functional Group Transformations of Tris(pyrazol-1-yl)meth­ane (Tpm) and -ethane (Tpe) Derivatives for the Preparation of Sterically Hindered Chelating Macrobicycles

Abstract

Tris(pyrazol-1-yl)methane (Tpm) and -ethane (Tpe) chelate derivatives bearing meta-benzonitrile groups in the position ortho to the coordinating nitrogen atom have been prepared from 3-(1H-pyrazol-3-yl)benzonitrile, and subjected to functional group transformations leading to the corresponding benzylthiol-substituted derivatives. The Tpe analogue was reacted with 1,3,5-tribromomethylbenzene in basic conditions to afford the Tpe-incorporating macrobicycle 2 in 40% yield.