Synthesis of aryl-substituted or aryl-fused N-hydroxyethyl and N-hydroxymethypyrazole derivatives as potential ligands for the estrogen receptor

A new series of N-hydroxyethylpyrazole (12a-f) and N-hydroxymethylpyrazole derivatives (15a-f) were designed for their estrogenic activities, having a 11.0 +/- 0.5 angstrom distance between their two hydroxyl groups, aliphatic-OH and phenolic-OH similar to 17 beta-estradiol (E2) as an endogenous hormone. To synthesize the title compounds, the key intermediate 1,3-dicarbonyl derivatives (2 and 8), were treated with hydrazine hydrate to produce the pyrazole ring 5 and 9. Further hydroxyalkylation of the latter produced the title pyrazoles. The position of hydroxyethyl or hydroxymethyl substituents in the products was determined through 2D NOE NMR spectroscopy.