Analogues of aminoglutethimide based on 1-phenyl-3-azabicyclo[3.1.0]hexane-2,4-dione: selective inhibition of aromatase activity

Copper(I)-Catalyzed Indolyl Ynamide Oxidation/Dearomatization: Divergent and Regioselective Synthesis of Valuable Indoline Scaffolds

A highly convenient copper(I)-catalyzed oxidation-initiated cyclopropanation of indolyl ynamide for the rapid construction of indole-fused cyclopropane-lactams is described, which represents, to the best of our knowledge, the first non-noble-metal-catalyzed indolyl ynamide oxidation/dearomatization by the in situ generated α-oxo copper carbenes. Compared to hydrazone and diazo, the use of alkynes as carbene precursors allows cyclopropanation to occur under a safe and convenient pathway. Moreover, this transformation can lead to the divergent synthesis of pentacyclic spiroindolines involving the reversal of ynamide regioselectivity by engineering substrate structures.

Base-promoted highly efficient synthesis of nitrile-substituted cyclopropanes via Michael-initiated ring closure

A convenient and efficient annulation reaction has been developed for the general synthesis of dinitrile-substituted cyclopropanes in moderate to excellent yields. A variety of 2-arylacetonitriles and α-bromoennitriles were compatible under the standard conditions. The reaction was achieved through tandem Michael-type addition followed by intramolecular cyclization. The preliminary application of this method was confirmed by the synthesis of the 2,4-dioxo-3-azabicyclo[3.1.0]hexane scaffold.

Copper(I)-Catalyzed Enyne Oxidation/Cyclopropanation: Divergent and Enantioselective Synthesis of Cyclopropanes

An efficient copper(I)-catalyzed enyne oxidation/cyclopropanation for the modular synthesis of cyclopropane derivatives is described, which represents the first non-noble metal-catalyzed enynes oxidation/cyclopropanation by the in situ generated α-oxo copper carbenes. This protocol allows the assembly of valuable cyclopropane-γ-lactams in generally good to excellent yields with excellent diastereoselectivity. More significantly, the enantioselective version of enyne oxidation/cyclopropanation has been disclosed with chiral copper catalysts.

Separation of the enantiomers of some racemic nonsteroidal aromatase inhibitors and barbiturates by capillary electrophoresis

High-performance capillary electrophoresis (HPCE) and micellar electrokinetic capillary chromatography (MECC) were applied to the resolution of racemic nonsteroidal antiaromatase drugs and intermediates. Successful results were obtained in both modes using alpha-cyclodextrin (alpha-CD), beta-cyclodextrin (beta-CD), gamma-cyclodextrin (gamma-CD), or 2,6-di-O-methyl-beta-cyclodextrin (DM-beta-CD) as chiral selectors. Depending on the structure of the solute, one of the cyclodextrins was generally better suited for resolution of the racemate. The basic solutes were analyzed under HPCE conditions, whereas the nonionizable compounds such as glutethimide (Doriden) were analyzed in MECC mode. For the azole-type antiaromatase Fadrozole, both HPCE and MECC modes could be used to achieve the separation of the enantiomers. The influence of experimental factors such as pH, the presence of organic modifier, temperature, the micelle concentration, and the concentration of the chiral selector is also discussed on the basis of the results obtained with some chiral barbiturates. The possibility of analyzing the enantiomers directly in plasma samples was also demonstrated.

Some 1-, and 3-substituted 3-(4'-aminophenyl)pyrrolidine-2,5-diones as selective inhibitors of aromatase

1-Alkyl-3-(4'aminophenyl)pyrrolidine-2,5-diones (7,R = C3H7-C7H15) are potent inhibitors of aromatase in vitro, the 1-hexyl (Ki = 62nM) being about 100-fold more potent than aminoglutethimide (AG), and more selective in their ratio of aromatase:CSCC inhibitory potency. The 1-pentyl, 1-hexyl and 1-heptyl derivatives are more stable to liver microsomal metabolism in vitro than AG possibly due to inhibition of the liver cytochrome P450s. 1,3-Dialkyl-3(4'-aminophenyl)pyrrolidine-2,5-diones (9) have been synthesised by a novel method. Although the higher homologues (di-pentyl and di-hexyl) are more potent in vitro as inhibitors of aromatase than AG, they are less active than their 1-alkyl counterparts with the same alkyl substituent.

Comparison of aromatase activity in human prostatic, testicular and placental tissues

The aromatase enzyme was quantified by the release of tritiated water from [1 beta-3H] androstenedione. Tritiated water was released by the crude homogenates in 4 of 18 samples of benign prostatic hyperplasia tissue and one of 5 samples of prostate carcinoma tissue. However, this apparent aromatase activity was not inhibited by 4-hydroxyandrostenedione (0.5 and 5.0 microM), and none of the particulate fractions (100,000 g pellet) prepared from each of the prostatic tissues exhibited aromatase activity. Particulate fractions from rat ovary (n = 3) and human testes (n = 6) displayed significant aromatase activity (mean values of 9.9 and 0.033 nmol estrone formed/g protein/h, respectively). The testicular aromatase was inhibited by aminoglutethimide, 4-hydroxyandrostenedione and CGS 16949A with IC50 values of 6.4, 0.17 and 0.0017 microM, respectively. These are of a similar order to values obtained with the aromatase enzyme from human placental microsomes (14, 0.43 and 0.0075 microM, respectively).