The annular tautomerism of the curcuminoid NH-pyrazoles
作者:Pilar Cornago、Pilar Cabildo、Rosa M. Claramunt、Latifa Bouissane、Elena Pinilla、M. Rosario Torres、José Elguero
DOI:10.1039/b812018h
日期:——
The structures of four NH-pyrazoles, (E)-3,5-bis[β-(4-hydroxy-3-methoxyphenyl)-ethenyl]-1H-pyrazole (3), (E)-3(5)-[β-(4-hydroxy-3-methoxyphenyl)-ethenyl]-5(3)-methyl-1H-pyrazole (4), (E)-3(5)-[β-(4-hydroxy-3-methoxyphenyl)-ethenyl]-4,5(3)-dimethyl-1H-pyrazole (5) and (E)-3(5)-[β-(3,4-dimethoxyphenyl)-ethenyl]-4-methyl-5(3)-phenyl-1H-pyrazole (8), have been determined by X-ray crystallography. Compounds that have a phenol residue crystallize forming sheets that are stabilized by a complex pattern of hydrogen bonds between a unique tautomer (4), or by a 2 : 1 mixture of both tautomers (5) (these tautomers being identical in the case of 3). Pyrazole 8, which lacks OH groups, crystallizes in cyclic dimers that are stabilized by N–H⋯N hydrogen bonds. The tautomerism in solution and in the solid state was determined by 13C and 15N CPMAS NMR spectroscopy. For compounds 4, 5 and 8, the solid state results agree with those observed by crystallography; the most abundant tautomer in solution coincides with the tautomer present in the solid state (4 and 8) or with the most abundant tautomer in the crystal (5).
Synthesis and biological evaluation of curcuminoid pyrazoles as new therapeutic agents in inflammatory bowel disease: Effect on matrix metalloproteinases
Seven N-unsubstituted curcuminoid pyrazoles have been synthesized from the corresponding beta-diketones ( including curcumin). We evaluated the possibility of curcuminoid pyrazoles regulating the activity of matrix metalloproteinases ( MMPs) by human intestinal epithelial cells in vitro. Zymographic analysis revealed that three compounds significantly down-regulated MMP-9 activity on inflammation-induced intestinal epithelial cells, making them original candidates for the treatment of inflammatory bowel disease (IBD). (c) 2008 Elsevier Ltd. All rights reserved.