Natália Seus

Room-Temperature Organocatalytic Cycloaddition of Azides with β-Keto Sulfones: Toward Sulfonyl-1,2,3-triazoles.

Organocatalytic enamine-azide [3 + 2] cycloadditions between β-keto sulfones and aryl azides can be performed at room temperature in good to excellent yields of products in the presence of catalytic amounts of pyrrolidine (5 mol %). The proposed organocatalytic methodology was found to be applicable to β-keto arylsulfones containing a range of substituents. A wide variety of aryl azides also work. Basically, this constitutes a remarkably efficient protocol for the synthesis of novel 1,2,3-triazole compounds.

Involvement of the dopaminergic and serotonergic systems in the antidepressant-like effect caused by 4-phenyl-1-(phenylselanylmethyl)-1,2,3-triazole.

AIMS The study investigated the antidepressant-like effect and acute toxicity of 4-phenyl-1-(phenylselanylmethyl)-1,2,3-triazole (Se-TZ), an organoselenium-containing heterocycle compound in mice. MAIN METHODS The antidepressant-like effect of Se-TZ (1-50mg/kg) and its mechanism of action, was analyzed in the tail suspension test (TST) in male C57BL/6J mice. Additionally, the levels of the monoamines and their metabolites in cerebral cortex and hippocampus were analyzed by high-performance liquid chromatography. To investigate the potential acute toxicity caused by Se-TZ, the mice received a single oral dose of Se-TZ (1-50mg/kg), and after 72h were performed the assays. KEY FINDINGS The Se-TZ (5-50mg/kg) significantly reduced immobility time in TST without altering locomotor and exploratory activities. The antidepressant-like effect of Se-TZ (25mg/kg) in the TST was prevented by pre-treatment of mice with SCH23390, sulpiride and methysergide, but not with prazosin, yohimbine and propranolol. Se-TZ, increased monoamine neurotransmitters dopamine and serotonin levels in the cerebral cortex and hippocampus, whereas norepinephrine turnover was not changed. This study also demonstrated that the Se-TZ, did not cause the acute toxicity in biochemical markers hepatic and renal investigated. The results evidenced that exposure to Se-TZ caused a significant increase in the catalase (CAT) activity in the cerebral cortex and hippocampus, however the glutathione S-transferase (GST) activity increased only in the cerebral cortex. SIGNIFICANCE These results suggest that Se-TZ demonstrated antidepressant-like effect, mediated via the central dopaminergic and serotoninergic neurotransmitter systems which may be of interest as a therapeutic agent for the treatment of depressive disorders.

Organocatalytic synthesis and evaluation of 7-chloroquinoline-1,2,3-triazoyl carboxamides as potential antinociceptive, anti-inflammatory and anticonvulsant agent

We describe herein our results on the organocatalytic synthesis and pharmacological properties of 7-chloroquinoline-1,2,3-triazoyl carboxamides. This class of compounds was synthesized in good to excellent yields by the reaction of 4-azido-7-chloroquinoline with a range of β-oxo-amides in the presence of a catalytic amount of pyrrolidine (5 mol%). The obtained compound 3a was screened for anticonvulsant, antinociceptive and anti-inflammatory activities in vivo. The results demonstrated that compound 3a was effective in decreasing the appearance of seizures induced by pilocarpine and pentylenetetrazole. In addition, compound 3a demonstrated antinoceptive and anti-inflammatory properties for combating acute pain. This protocol is an efficient method for the production of new heterocyclic compounds with pharmacological activities.

Phenylselanyl-1H-1,2,3-triazole-4-carbonitriles: synthesis, antioxidant properties and use as precursors to highly functionalized tetrazoles

We describe herein our results on the synthesis, antioxidant properties and chemical diversification of phenylselanyl-1H-1,2,3-triazole-4-carbonitriles. These compounds were synthesized in high yields by the reaction of azidophenyl phenylselenides with a range of α-keto nitriles, using DMSO as the solvent in the presence of a catalytic amount of Et2NH (1 mol%). The synthesized compounds were screened for their in vitro antioxidant activity and 5-phenyl-1-(2-(phenylselanyl)phenyl)-1H-1,2,3-triazole-4-carbonitrile (3a) exhibited the highest antioxidant effect. In addition, the obtained triazoyl carbonitriles were readily transformed into more complex products via a cycloaddition protocol with NaN3, affording bifunctional hybrids containing triazole and tetrazole systems in good to excellent yields.

Sonochemistry in organocatalytic enamine-azide [3+2] cycloadditions: A rapid alternative for the synthesis of 1,2,3-triazoyl carboxamides

We described herein the use of sonochemistry in the organocatalytic enamine-azide [3+2] cycloadditions of β-oxo-amides with a range of substituted aryl azides. These sonochemical promoted reactions were found to be amenable to a range of β-oxo amides or aryl azides, providing an efficient access to new N-aryl-1,2,3-triazoyl carboxamides in good to excellent yields and short times of reaction.

Ultrasound-promoted organocatalytic enamine–azide [3 + 2] cycloaddition reactions for the synthesis of ((arylselanyl)phenyl-1H-1,2,3-triazol-4-yl)ketones

The use of sonochemistry is described in the organocatalytic enamine–azide [3 + 2] cycloaddition between 1,3-diketones and aryl azidophenyl selenides. These sonochemically promoted reactions were found to be amenable to a range of 1,3-diketones or aryl azidophenyl selenides, providing an efficient access to new ((arylselanyl)phenyl-1H-1,2,3-triazol-4-yl)ketones in good to excellent yields and short reaction times. In addition, this protocol was extended to β-keto esters, β-keto amides and α-cyano ketones. Selanyltriazoyl carboxylates, carboxamides and carbonitriles were synthesized in high yields at short times of reaction under very mild reaction conditions.

Evaluation of Se-phenyl-thiazolidine-4-carboselenoate protective activity against oxidative and behavioral stress in the maniac model induced by ouabain in male rats

This study investigates Se-phenyl-thiazolidine-4-carboselenoate (Se-PTC) protective activity against oxidative and behavioral stress in the model of mania induced by ouabain (OUA) in male rats. The compound used was Se-PTC (50mg/kg) and the positive control LiCl (45mg/kg) was administered for intragastric route (i.g.) 30min prior to administration of OUA (10-5M). OUA was dissolved in artificial cerebrospinal fluid (aCSF) and administered at the 5μl through an intracerebroventricular (i.c.v) cannula. The pretreatment with Se-PTC was effective in preventing the increase in locomotor activity induced by OUA, however the positive control LiCl is capable to block crossing augmentation induced by OUA. Na+/K+-ATPase activity was significantly reduced in OUA group and the Se-PTC to normalize Na+/K+-ATPase activity. Pretreatment with Se-PTC protect against the increase in catalase activity and thiobarbituric acid reactive species (TBARS) content in the brain caused by OUA. Therefore, Se-PTC is effective against OUA-induced hyperactivity and alterations in brain oxidative status of rats.