Acyclic amides as estrogen receptor ligands: Synthesis, binding, activity and receptor interaction
摘要:
We have prepared a series of bisphenolic amides that mimic bibenzyl and homobibenzyl motifs commonly found as substructures in ligands for the estrogen receptor (ER). Representative members were prepared from three classes: N-phenyl benzamides, N-phenyl acetamides, and N-benzyl benzamides; in some cases the corresponding thiocarboxamides and sulfonamides were also prepared. Of these three classes, the N-phenyl benzamides had the highest affinity for ER, the N-phenyl acetamides had lower, and the N-benzyl benzamides were prone to fragmentation via a quinone methide intermediate. In the N-phenyl benzamide series, the highest affinity analogues had bulky N-substituents; a CF3 group, in particular, conferred high affinity. The thiocarboxamides bound better than the corresponding carboxamides and these bound better than the corresponding sulfonamides. Binding affinity comparisons suggest that the p-hydroxy group on the benzoate ring, which contributes most to the binding, is playing the role of the phenolic hydroxyl of estradiol. Computational studies and NMR and X-ray crystallographic analysis indicate that the two anilide systems studied have a strong preference for the s-cis or exo amide conformation, which places the two aromatic rings in a syn orientation. We used this structural template. together with the X-ray structure of the ER ligand binding domain, to elaborate an additional hydrogen bonding site on a benzamide system that elevated receptor binding further. When assayed on the individual ER subtypes, ER alpha and ER beta, these compounds show modest binding affinity preference for ER alpha. In a reporter gene transfection assay of transcriptional activity, the amides generally have full to nearly full agonist character on ERa, but have moderate to full antagonist character on ER beta. One high affinity carboxamide is 500-fold more potent as an agonist on ER alpha than on ER beta. This work illustrates that ER ligands having simple amide core structures can be readily prepared, but that high affinity binding requires an appropriate distribution of bulk, polarity, and functionality. The strong conformational preference of the core anilide function in all of these ligands defines a rather rigid geometry for further structural and functional expansion of these series. (C) 2000 Elsevier Science Ltd. All rights reserved.
An enantioselective hydrogenation of simple fluorinated imines has been developed using Pd(OCOCF3)2/(R)-Cl-MeO-BIPHEP as a catalyst, and up to 94% ee was achieved. This method provides an efficient route to enantioenriched fluorinatedamines.
Palladium(II)-Catalyzed Enantioselective Synthesis of α-(Trifluoromethyl)arylmethylamines
作者:Thomas Johnson、Mark Lautens
DOI:10.1021/ol401862g
日期:2013.8.16
[GRAPHICS]Trifluoromethylacetaldimines, generated in situ from the corresponding N,O-acetals, undergo 1,2-addition of arylboroxines under palladium(II) catalysis to generate a variety of alpha-(trifluoromethyl)arylmethylamines with good to high enantioselectivity (up to 97% ee). The pyridine-oxazolidine (PyOX) class of ligands was found to be particularly suitable for this transformation, which proceeds without exclusion of ambient air and moisture.
Preparation of Tri- and Difluoromethylated Amines from Aldimines Using (Trifluoromethyl)trimethylsilane
作者:G. K. Surya Prakash、Ryo Mogi、George A. Olah
DOI:10.1021/ol061357w
日期:2006.8.1
Addition of a trifluoromethyl group into aldimines was accomplished using ( trifluoromethyl) trimethylsilane with tetraalkylammonium fluorides as initiators, and the resulting adducts were converted to difluoromethylated imines in the presence of excess fluoride. The imines were reduced to difluoromethylated amines using sodium borohydride.
Novel and effective synthesis of trifluoromethylated amines by use of an combination
作者:Yasuo Yokoyama、Kunio Mochida
DOI:10.1016/s0040-4039(97)00641-2
日期:1997.5
Efficient synthesis of trifluoromethylated amine derivatives by use of an Et3GeNa/C6H5SCF3 combination is described. This reaction proceeded smoothly to give the desired compound in excellent yield. (C) 1997 Elsevier Science Ltd.