C. Pask, Kenneth D. Camm, C. Kilner
Apr 10, 2006
Citations
0
Influential Citations
26
Citations
Journal
Tetrahedron Letters
Abstract
An improved synthesis of 3{5}-amino-5{3}-(pyrid-2-yl)-1 H -pyrazole ( I ) is described, which affords the compound on a multi-gram scale. Reaction of I with acid chloride and isothiocyanate electrophiles in MeCN cleanly results in attack at its amino group, yielding N -(3-{pyrid-2-yl}-1 H -pyrazol-5-yl)amide and N -(3-{pyrid-2-yl}-1 H -pyrazol-5-yl)thiourea products. These are good candidates as proligands for the simultaneous complexation of metal cations and anions. However, treatment of I with isocyanates under the same conditions instead yields attack at the pyrazole ring, giving 3-(pyridin-2-yl)-5-aminopyrazole-1-carboxylic acid amides as the only isolable products. The differing regiochemistries of these reactions were confirmed by 1 H NMR and X-ray crystallography.