Synthesis, biological evaluation and 3D-QSAR of 1,3,5-trisubstituted-4,5-dihydro-(1H)-pyrazole derivatives as potent and highly selective monoamine oxidase A inhibitors.
The present report provides a extended study of the chemistry, the inhibitory activity against monoamino oxidases (MAO), and molecular modeling including the 3D-QSAR hypothesis of 1,3,5-trisubstituted-4,5-dihydro-(1H)-pyrazole derivatives. Four series of about eighty novel pyrazoline derivatives were prepared and investigated for their ability to inhibit the activity of the A and B isoforms of MAO selectively. Most of the new synthesized compounds proved more reversible, potent, and selective inhibitors of MAO-A than of MAO-B, and could be taken into account to develop the search further in this field, knowing that reversible and selective MAO-A inhibitors are used as antidepressant and antianxiety drug. The 30 most active compounds show inhibitory activity on MAO-A in the 8.6 x 10(-8) - 9.0 x 10(-9)M range. Moreover, it should be pointed out that for most of them a high IC(50) > or = 10(-9)M value is associated with a high A-selectivity (Selectivity Index MAO-B/MAO-A in the 10,000-16,250 range). Furthermore, due to the presence of a chiral centre at the C5 position of the pyrazole moiety, we performed the semi-preparative chromatographic enantioseparation of the most potent, selective, and chiral compounds. The separated enantiomers were then submitted to in vitro biological evaluation, and from the results of these experiments it has been possible to point out a difference in inhibiting the two isoforms selectively between the racemic mixture and the single enantiomers. The molecular modeling work was carried out combining the Glide docking approach with CoMFA with the aim to rationalize the structure-activity relationships of each pyrazoline inhibitor toward MAO-A and MAO-B isoforms and to derive a suitable selectivity model.
Chimenti
Franco
F
Dipartimento di Studi di Chimica e Tecnologia delle Sostanze Biologicamente Attive, Università degli Studi di Roma La Sapienza, Piazzale Aldo Moro 5, 00185 Rome, Italy. franco.chimenti@uniroma1.it
Bolasco
Adriana
A
Manna
Fedele
F
Secci
Daniela
D
Chimenti
Paola
P
Granese
Arianna
A
Befani
Olivia
O
Turini
Paola
P
Cirilli
Roberto
R
La Torre
Francesco
F
Alcaro
Stefano
S
Ortuso
Francesco
F
Langer
Thierry
T
D000818:Animals; D001665:Binding Sites; D006801:Humans; D020128:Inhibitory Concentration 50; D008956:Models, Chemical; D008995:Monoamine Oxidase / Q000378:metabolism*; D008996:Monoamine Oxidase Inhibitors / Q000138:chemical synthesis* / Q000494:pharmacology; D011720:Pyrazoles / Q000138:chemical synthesis* / Q000494:pharmacology; D021281:Quantitative Structure-Activity Relationship; D013237:Stereoisomerism
D008996:Monoamine Oxidase Inhibitors; D011720:Pyrazoles; D008995:Monoamine Oxidase