Phenolic metabolites of clomiphene: [(E,Z)-2-[4-(1,2-diphenyl-2-chlorovinyl)phenoxy]ethyl]diethylamine. Preparation, electrophilicity, and effects in MCF 7 breast cancer cells.
The triarylethylene antiestrogen clomiphene was previously shown to undergo biotransformation to an active metabolite, 4-hydroxyclomiphene, and to 3-methoxy-4-hydroxyclomiphene plus the respective regioisomers of these, 4 and 5. We now report the synthesis and further chemical and biochemical studies on 3-5. Coupling of 4-[2-(diethylamino)ethoxy]benzophenone with either 4-(benzyloxy)benzaldehyde or its 3-methoxy analogue 11b in the presence of titanium, followed by chlorination and deprotection of the intermediate triarylethylenes, gave 4 and 5, respectively. Condensation of benzylmagnesium chloride with the (2-methoxyethoxy)methyl (MEM) ether of 4-[2-(diethylamino)ethoxy]-3'-methoxy-4'-hydroxybenzophenone, followed by mild acid treatment, afforded deschloro 3 due to facile MEM ether hydrolysis. Acetylation of this, followed by chlorination and deacetylation, gave 3. Compounds 4 and 5 reacted readily with nucleophiles. In particular, 2-mercaptoethanol reacted with 4 to afford deschloro vinyl thioether 13 as suggested by NMR spectral studies, a result that implicated allene-quinone 14 as the electrophilic species produced in solution from 4. Antiestrogen binding sites and estrogen receptors from MCF 7 human breast cancer cells interacted with 3 and 5 with affinities comparable to those of tamoxifen and 1, respectively; 5 was shown not to bind irreversibly with these sites. Inhibition of MCF 7 cell proliferation by 3-5 at 5 microM concentrations (76%, 57%, and 49%, respectively, relative to drug-free controls) compared favorably to that observed with 5 microM 1 (80%). These results suggest that 3-5 as well as 2 may contribute to the antiestrogenic effects of 1.
Ruenitz
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PC
College of Pharmacy, University of Georgia, Athens 30602.
Arrendale
R F
RF
Schmidt
W F
WF
Thompson
C B
CB
Nanavati
N T
NT
D001667:Binding, Competitive; D001943:Breast Neoplasms / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D055598:Chemical Phenomena; D002621:Chemistry; D002996:Clomiphene / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000494:pharmacology; D004965:Estrogen Antagonists / Q000138:chemical synthesis* / Q000378:metabolism / Q000494:pharmacology; D005260:Female; D006801:Humans; D011960:Receptors, Estrogen / Q000187:drug effects; D013329:Structure-Activity Relationship; D014407:Tumor Cells, Cultured
D004965:Estrogen Antagonists; D011960:Receptors, Estrogen; C058123:3-methoxy-4-hydroxyclomiphene; C058126:1-(phenyl)-1-(4-(2-(diethylamino)-ethoxy)phenyl)-2-(4-hydroxyphenyl)-2-chloroethane; C058127:1-(4-(2-(diethylamino)ethoxy)-phenyl)-1-(phenyl)-2-(3-methoxy-4-hydroxyphenyl)-2-chloroethane; D002996:Clomiphene