- Synthesis and evaluation of 10β-substituted 4-estrene-3,17-diones as inhibitors of human placental microsomal aromatase
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This paper describes the synthesis of a series of new 10β-substituted 4-estrene-3,17-dione analogs. These compounds, together with a number of known analogs, have been evaluated as reversible or irreversible inhibitors of human placental microsomal aromatase. The best reversible inhibitor is the 10β-vinyl compound. The only compounds causing irreversible inhibition of aromatase are the 10β-propargyl compound and the 10β-difluoromethyl compound.
- Marcotte,Robinson
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- Process for the preparation of 10(2-propynyl)estr-4-ene-3,17-dione
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This invention relates to a process for the preparation of 10-(2-propynyl)-estr-4-ene-3,17-dione, whereby this compound is synthesized utilizing ketals prepared from the addition of 2,2-dimethyl-1,3-propanediol to the starting compound, 19-norandrost-5(10)-ene-3,17-dione (NAD). A new process for the addition of the propynyl group to steroid epoxides by means of higher order cuprates is also described herein.
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- Interactions of Thiol-Containing Androgens with Human Placental Aromatase
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A series of thiol androgens were synthesized and investigated to characterize structural features important for the inhibition of aromatase.Analogues of androstenedione with thiol groups in either the 2α-, 10β-, or 19-positions caused time-dependent inhibition of human placental aromatase.When their KI and kcat values were compared with those of 4-hydroxyandrost-4-ene-3,17-dione (4-OHa) and 10-β-propargylestr-4-ene-3,17-dione (PED), the thiol androgen 10β-mercaptoestr-4-ene-3,17-dione (10β-SHnorA) proved to be the most potent suicide substrate.However, 19-merc aptoandrost-4-ene-3,17-dione (19-SHA) was the best all-around inhibitor.All compounds except 19-SHA exhibited normal type I P-450 difference spectra with partially purified/solubilized, human placental aromatase.The KS values for the series of compounds compared qualitatively to the KI values determined from the time and concentration-dependent inhibition experiments. 19-SHA induced split Soret peaks at 380 and 474 nm, which suggested binding of the 19-thiolate directly to the ferric iron of aromatase.This binding could be displaced by aminoglutethimide but not by androstenedione.The inhibitory activity of 19-SHA may be explained by two independent mechanisms: (1) suicide inactivation of aromatase in the ferrous state; and (2) a direct "hyper-type II" binding to the remaining portion of the cytochrome in the ferric state.A free thiol group was necessary for the suicide inhibitory activity of 19-SHA; time-dependent inactivation of aromatase by 19-(acetylthio)androst-4-ene-3,17-dione (19-SAcA) and 19-xanthogenylandrost-4-ene-3,17-dione (19-XanA) could be prevented if the microsomes were preincubated with a carboxyesterase inhibitor.Aromatase previously inactivated by either thiol androgens, 4-OHA, or PED could not be reactivated after incubation with the disulfide reducing agent dithiothreitol, which suggests that a disulfide bond may not be involved in aromatase inactivation by these inhibitors.
- Bednarski, Patrick J.,Nelson, Sidney D.
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p. 203 - 213
(2007/10/02)
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- 10-Alkynyl steroids
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Aromatase inhibitors are provided having the formula STR1 wherein represents a single or double bond; R is hydrogen or C1-4 alkyl; R1 is methyl or ethyl; R2 is (H) (OR8) or =O; R3 is H or C1-3 alkyl; R4 is H or OR8 ; R5 is H, C1-3 alkyl or, when the 5,6-bond is saturated, R5 is divalent =O; R6 and R7 are each H or C1-3 alkyl; and R8 is H or C2-4 alkanoyl. Intermediates useful in preparing the foregoing aromatase inhibitors, and methods of using the aromatase inhibitors of the invention are also provided.
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