Iodoindazoles with Selective Magnesiation at Position 3: A Route to Highly Functionalized Indazoles.

A unique route to highly functionalized indazoles is described. A regioselective magnesiation at position 3 of 4-, 5-, 6- and 7-iodo-2-THP-indazoles (THP=tetrahydropyranyl) has been developed using TMPMgCl⋅LiCl (TMP=2,2,6,6-tetramethylpiperidyl). The obtained magnesiate can be trapped by different electrophiles to introduce a wide range of functional groups including halogens, thioalkyls, alcohols, aldehydes, ketones, amides, or esters at position 3. Once this position is functionalized, the iodine atoms can be further reacted through metal-halogen exchange or cross-coupling strategies. Finally, N-substitution reactions allow the synthesis of a variety of highly functionalized indazoles giving access to these valuable scaffolds through a simple and unique route.

New hypotheses for the binding mode of 4- and 7-substituted indazoles in the active site of neuronal nitric oxide synthase.

Taking into account the potency of 4- and 7-nitro and haloindazoles as nNOS inhibitors previously reported in the literature by our team, a multidisciplinary study, described in this article, has recently been carried out to elucidate their binding mode in the enzyme active site. Firstly, nitrogenous fastening points on the indazole building block have been investigated referring to molecular modeling hypotheses and thanks to the in vitro biological evaluation of N(1)- and N(2)-methyl and ethyl-4-substituted indazoles on nNOS. Secondly, we attempted to confirm the importance of the substitution in position 4 or 7 by a hydrogen bond acceptor group thanks to the synthesis and the in vitro biological evaluation of a new analogous 4-substituted derivative, the 4-cyanoindazole. Finally, by opposition to previous hypotheses describing NH function in position 1 of the indazole as a key fastening point, the present work speaks in favour of a crucial role of nitrogen in position 2.

Virtual screening discovery of new acetylcholinesterase inhibitors issued from CERMN chemical library.

In our quest to find new inhibitors able to inhibit acetylcholinesterase (AChE) and, at the same time, to protect neurons from beta amyloid toxicity, i.e., inhibitors interacting with the catalytic anionic subsite as well as with the peripherical anionic site of AChE, a virtual screening of the Centre d'Etudes et de Recherche sur le Medicament de Normandie (CERMN) chemical library was carried out. Two complementary approaches were applied, i.e., a ligand- and a structure-based screening. Each screening led to the selection of different compounds, but only two were present in both screening results. In vitro tests on AChE showed that one of those compounds presented a very good inhibition activity, of the same order as Donepezil. This result shows the real complementary of both methods for the discovery of new ligands.

Synthesis and biological evaluation of new donepezil-like Thiaindanones as AChE inhibitors.

Pharmacomodulations of previously reported thiaindanones related to donepezil were achieved with the aim to enhance their AChE inhibitory activity. Condensation of the cyclopentane carbonyl group into hydrazone or cyanolefine derivatives, as well as its hydrogenation and the subsequent substitution of the resulting hydroxyl group led to new 2-(4-benzylpiperazin-1-yl)-N-(1,3-dibromo-6-hydroxy-5,6-dihydro-4H-cyclopenta[c]thien-4-yl) acetamides. The in vitro evaluation of this new series, according to the method of Ellman, shows however that it conserved only partially the biological activity. The best compound remains the alcohol 11 (IC(50) = 0.40 microM, against 0.02 microM for donepezil).

Synthesis and biological evaluation as AChE inhibitors of new indanones and thiaindanones related to donepezil.

Sixty-four new indanones and thiaindanones related to donepezil were synthesized and evaluated in vitro as potential AChE inhibitors. Among them, 11 derivatives were found to inhibit the enzyme in the submicromolar range; the best compound revealed its inhibitory activity with an IC50 in the same range (0.06 microM) than the reference compound, donepezil (IC50=0.02 microM).

4-substituted indazoles as new inhibitors of neuronal nitric oxide synthase.

A series of halo-1-H-indazoles has been synthesized and evaluated for its inhibitory activity on neuronal nitric oxide synthase. Introduction of bromine at the C4 position of the indazole ring system provided a compound almost as potent as the reference compound, that is, 7-nitroindazole (7-NI). The importance of position 4 is further demonstrated by the synthesis and pharmacological evaluation of the 4-nitroindazole which was also a potent inhibitor of NOS activity. These compounds also exhibited in vivo NOS inhibitory activity, as attested by potent antinociceptive effects following systemic administration.