RESUMEN
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 TMPMgClâ 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.
RESUMEN
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.
Asunto(s)
Inhibidores Enzimáticos/farmacología , Indazoles/farmacología , Óxido Nítrico Sintasa de Tipo I/antagonistas & inhibidores , Sitios de Unión/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Humanos , Indazoles/síntesis química , Indazoles/química , Modelos Moleculares , Estructura Molecular , Óxido Nítrico Sintasa de Tipo I/metabolismo , Relación Estructura-ActividadRESUMEN
This review lists the most important radiotracers described so far for imaging the central serotoninergic system. Single-photon emission computed tomography and positron emission tomography radiotracers are reviewed and critically discussed for each receptor.
RESUMEN
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.
Asunto(s)
Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Indazoles/química , Indazoles/farmacología , Óxido Nítrico Sintasa de Tipo I/antagonistas & inhibidores , Animales , Bromo/química , Cerebelo/citología , Cerebelo/efectos de los fármacos , Cerebelo/enzimología , Inhibidores Enzimáticos/síntesis química , Indazoles/síntesis química , Neuronas/efectos de los fármacos , Neuronas/enzimología , Ratas , Relación Estructura-ActividadRESUMEN
The crystal structure of 7-methoxy-1H-indazole, C(8)H(8)N(2)O, an inhibitor of nitric oxide synthase, shows that the methoxy group lies in the plane of the indazole system with its methyl group located trans to the indazole N-H group. The crystal packing consists principally of hydrogen-bonded trimers. Intermolecular hydrogen-bonding interactions are formed between the indazole N atoms, with the N-H group as a hydrogen-bond donor and the remaining N atom as an acceptor.
Asunto(s)
Inhibidores Enzimáticos/farmacología , Indazoles/farmacología , Óxido Nítrico Sintasa/antagonistas & inhibidores , Cristalografía por Rayos X , Inhibidores Enzimáticos/química , Enlace de Hidrógeno , Indazoles/química , Modelos Moleculares , Estructura Molecular , Óxido Nítrico Sintasa de Tipo IRESUMEN
Regioselective and univocal Suzuki cross-coupling reactions performed on halopyridinyl boronic acids provide a flexible and versatile route to a multigram scale synthesis of 2,2'-dichloro-3,4'-bipyridine 14, which allows couplings with excess pyridin-3-yl boronic acid to give a new and efficient two-step rapid synthesis of nemertelline, the quaterpyridine neurotoxin isolated from a Hoplonemertine sea worm.
Asunto(s)
Neurotoxinas/síntesis química , Piridinas/síntesis química , Ácidos Borónicos/química , Estructura Molecular , EstereoisomerismoRESUMEN
A series of isomeric methoxyindazoles has been evaluated as inhibitors of purified recombinant neuronal, inducible, and endothelial nitric oxide synthases (NOS). 7-Methoxyindazole (7-MI) was the most active compound of this series and displayed selectivity toward the constitutive neuronal (NOS I) and endothelial (NOS III) NOS isoforms, the inducible NOS II being almost insensitive to this inhibitor. 6-, 5-, and 4-Methoxyindazoles were almost inactive against all three NOS isoforms. Inhibition of NO and citrulline formation catalyzed by neuronal NOS in the presence of 7-MI appeared to be competitive versus both substrate L-arginine (L-arg) and (6R)-5,6,7,8-tetrahydrobiopterin (BH(4)) cofactor. 7-MI only slightly inhibited NADPH oxidase activity and was inactive against the cytochrome c (cyt c) reductase activity of neuronal NOS at concentrations up to 100-fold higher than its IC(50) value for inhibition of citrulline formation. UV/Vis and EPR studies indicated that 7-MI interacts with the oxygenase domain of neuronal NOS (NOS I(oxy)) in an identical manner but with a much lower affinity than 7-nitroindazole (7-NI). These results demonstrate that an indazole derivative bearing an electron-rich substituent in the 7-position is also a NOS I inhibitor and that such a compound presents strong similarities with the mechanism of inhibition of 7-NI.
Asunto(s)
Inhibidores Enzimáticos/farmacología , Indazoles/farmacología , Óxido Nítrico Sintasa/antagonistas & inhibidores , Arginina/metabolismo , Citrulina/metabolismo , Citocromos c/metabolismo , Espectroscopía de Resonancia por Spin del Electrón , Isoenzimas , NADP/metabolismo , Óxido Nítrico Sintasa/metabolismo , Proteínas Recombinantes/antagonistas & inhibidores , Proteínas Recombinantes/metabolismo , Espectrofotometría UltravioletaRESUMEN
The synthesis, pharmacological evaluation and modelisation of 7-methoxyindazole (7-MI) and related alkoxyindazoles as novel inhibitors of neuronal nitric oxide synthase are presented. 7-MI remains the most active compound of this series in an in vitro enzymatic assay of neuronal nitric oxide synthase activity. Modeling studies of the interaction of 7-substituted indazole derivatives complexed with nNOS and the relationship with their respective biological activities suggest that a bulky substitution on position-7 is responsible for a steric hindrance effect which does not allow these compounds to interact with nNOS in the same way as 7-NI and 7-MI.
Asunto(s)
Inhibidores Enzimáticos , Indazoles , Óxido Nítrico Sintasa/antagonistas & inhibidores , Animales , Cerebelo/enzimología , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Técnicas In Vitro , Indazoles/síntesis química , Indazoles/química , Indazoles/farmacología , Modelos Químicos , Estructura Molecular , Óxido Nítrico Sintasa de Tipo I , Ratas , Relación Estructura-ActividadRESUMEN
A series of 22 cyclopenta[c]thiophene related compounds was obtained by the pharmacomodulation of 6-amino-5,6-dihydro-4H-cyclopenta[c]thiophen-4-ones 1a-g. All compounds were evaluated for potential anticancer activity in the NCI's in vitro human disease-oriented tumor cell line screening panel that consisted of 60 human tumor cell lines arranged in nine subpanels, representing diverse histologies. Among these tested compounds, seven were found to be cytotoxic, especially against leukemia cell lines, allowing us to point out some structure-activity relationships. These derivatives were further evaluated for potential in vivo anticancer activity in the hollow fiber assay developed at the NCI, which selected two compounds, 1f and 3a for standard xenograft testing.
Asunto(s)
Antineoplásicos/síntesis química , Antineoplásicos/farmacología , Tiofenos/síntesis química , Tiofenos/farmacología , Antineoplásicos/química , Evaluación Preclínica de Medicamentos , Humanos , Espectroscopía de Resonancia Magnética , Tiofenos/químicaRESUMEN
A series of 10 derivatives 2-6 issued from the fusion of various five-membered heterocycles to cyclopenta[c]thiophene were evaluated for potential anticancer activity in the NCI's in vitro human disease-oriented tumor cell line screening panel that consisted of 60 human tumor cell lines arranged in nine subpanels, representing diverse histologies. Among these tested compounds, four were found to be cytotoxic allowing us to point out some structure-activity relationships. The oxazolidinone derivatives 2a-c displayed further in vivo antitumor activity in the hollow fiber assay and standard xenograft testing developed at the NCI.