Fluorinated phenylcyclopropylamines. Part 5: Effects of electron-withdrawing or -donating aryl substituents on the inhibition of monoamine oxidases A and B by 2-aryl-2-fluoro-cyclopropylamines
摘要:
A series of racemic, diastereoisomeric aryl cyclopropylamines substituted with fluorine in the 2-position and electron-donating and electron-withdrawing groups on the aromatic ring have been prepared. These represent analogues of the classic MAO inhibitor tranylcypromine (trans-2-phenylcyclopropylamine, 1). Their activities as inhibitors of recombinant human liver monoamine oxidases A (MAO A) and B (MAO B) were determined. The trans-compounds were low micromolar inhibitors of both MAO A and MAO B with moderate MAO A selectivity while the less active cis-analogues were MAO B selective. In the trans-series, electron-withdrawing para-substituents increased the potency of MAO A inhibition while electron-donating groups such as methyl or methoxy had no influence on this activity. In contrast, aromatic ring substitution in the trans-series had essentially no effect on the inhibition of MAO B. The corresponding cis-compounds were shown to be 10-100 times less active against MAO A, while trans-and cis-compounds were quite similar in terms of inhibition of MAO B. The best MAO A/ MAO B selectivity (7: 1) in the trans-series was found for trans-2-fluoro-2-(para-trifluoromethylphenyl) cyclopropylamine (7d), while a 1: 27 selectivity was found for cis-2-fluoro-2-(para-fluorophenyl) cyclopropylamine (10c). These results are discussed in connection with the pK(a) and logD values, the mechanism of action of tranylcypromines, and the geometry of the active site of the enzymes. (C) 2008 Elsevier Ltd. All rights reserved.
respectively, were obtained. An advantage of the latter protocol is the in situ formation of ethyldiazoacetate from ethyl glycinate hydrochloride in aqueous solution by diazotation avoiding the in-substance application of the potentially explosive ethyldiazoacetate. Accordingly, a series of diastereoisomeric ethyl 2-aryl-2-fluoro-cyclopropane carboxylates was synthesized from p- or m-substituted α-fluorostyrenes
Fluorinated phenylcyclopropylamines. Part 5: Effects of electron-withdrawing or -donating aryl substituents on the inhibition of monoamine oxidases A and B by 2-aryl-2-fluoro-cyclopropylamines
作者:Svenja Hruschka、Thomas C. Rosen、Shinichi Yoshida、Kenneth L. Kirk、Roland Fröhlich、Birgit Wibbeling、Günter Haufe
DOI:10.1016/j.bmc.2008.06.048
日期:2008.8
A series of racemic, diastereoisomeric aryl cyclopropylamines substituted with fluorine in the 2-position and electron-donating and electron-withdrawing groups on the aromatic ring have been prepared. These represent analogues of the classic MAO inhibitor tranylcypromine (trans-2-phenylcyclopropylamine, 1). Their activities as inhibitors of recombinant human liver monoamine oxidases A (MAO A) and B (MAO B) were determined. The trans-compounds were low micromolar inhibitors of both MAO A and MAO B with moderate MAO A selectivity while the less active cis-analogues were MAO B selective. In the trans-series, electron-withdrawing para-substituents increased the potency of MAO A inhibition while electron-donating groups such as methyl or methoxy had no influence on this activity. In contrast, aromatic ring substitution in the trans-series had essentially no effect on the inhibition of MAO B. The corresponding cis-compounds were shown to be 10-100 times less active against MAO A, while trans-and cis-compounds were quite similar in terms of inhibition of MAO B. The best MAO A/ MAO B selectivity (7: 1) in the trans-series was found for trans-2-fluoro-2-(para-trifluoromethylphenyl) cyclopropylamine (7d), while a 1: 27 selectivity was found for cis-2-fluoro-2-(para-fluorophenyl) cyclopropylamine (10c). These results are discussed in connection with the pK(a) and logD values, the mechanism of action of tranylcypromines, and the geometry of the active site of the enzymes. (C) 2008 Elsevier Ltd. All rights reserved.
Reaction of tertiary cyclopropyl silyl ethers with diethylaminosulfur trifluoride: the effects of substituents on the cleavage of the cyclopropane ring
The reaction of tertiary cyclopropanol silyl ethers with diethylaminosulfur trifluoride usually causes ringopening to produce allylic fluorides. However, cyclopropyl silyl ethers bearing a strong electron-donating substituent at C1 or an electron-withdrawing substituent at C2 do not afford allylic fluorides but fluorocyclopropanes. It has also been proved that an electron-donating substituent at C2