1 - -3,5 dimethylpyrazole, reaction with metal

The present paper describes the synthesis of N-(2-hydroxyethyl)-3,5-dimethylpyrazole and the synthesis of the tosylated compound N-(2-p-tol-uenesulfonylethyl)-3,5-dimethylpyrazole which can be used for the synthesis of larger chelating ligands. The tosylation is carried out in a water/acetone mixture, unlike most classical tosylations, which are performed in pyridine.7 A high yield of pure tosylated product is obtained from this reaction. A water/acetone mixture as the solvent for the synthesis of other tosylates may very well be also successful. Since the compound N-(2-hydroxyethyl)-3,5-dimethylpyrazole may itself act as a didentate N,0 ligand in coordination compounds with transition metal ions,9 an example using Cu(II) is provided below. 

It is possible to use ancillary ligands in addition to phosphonic acids in building up nanosized cluster compounds of late transition metal ions. Thus, the reaction of CuCl2 with tert-butylphosphonic acid in the presence of 3,5-dimethylpyrazole affords a dodecanuclear copper phosphonate with an interesting cage structure,3 Similarly, large vanadium phosphonate clusters with up to 18 vanadium atoms have been assembled from phosphonic acids.35... 

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