Plants and essential oils (EOs) have been used for centuries in folk medicine to treat diverse disorders, including analgesic to pain relief. In this context, the antinociceptive activity of EOs has been attracted attention since the management of pain continues being a major challenge for medicine. This review provides an overview of published reports on the antinociceptive activity of EOs and their constituents from 2000 until the first half of 2015. In this review are compiled the data on the antinociceptive activity of 63 EOs and 26 of their constituents with a discussion about the nociception model used to access the analgesic effect. These data were also analyzed in relation to ethnopharmacological and toxicological data available in the literature. As can be seen by the analysis of more than 300 articles, EOs and their constituents show antinociceptive effects in different models and their action mechanism is quite variable. Although there are a few essential oils or their isolated constituents on the phytopharmaceuticals market, this review intends to put in evidence the often-underexploited vast source of natural compounds with therapeutic potential in pain relief.

We describe herein our results on the synthesis and antioxidant properties of 7-chloroquinoline-1,2,3-triazoyl-4-carboxylates. This class of compounds have been synthesized in moderated to excellent yields by the reaction of 4-azido-7-chloroquinoline with a range of β-ketoesters in the presence of a catalytic amount of pyrrolidine (10 mol%). The synthesized compounds ethyl 1-(7-chloroquinolin-4-yl)-5-methyl-1H-1,2,3-triazole-4-carboxylate and ethyl 1-(7-chloroquinolin-4-yl)-5-phenyl-1H-1,2,3-triazole-4-carboxylate were screened for their in vitro antioxidant activity and the results demonstrated that the first compound reduces the lipid peroxidation levels induced by sodium nitroprusside in liver of mice, while the second compound shown nitric oxide scavenging activity. This is an efficient method to produce new heterocyclic compounds with potential antioxidant activities.

Um método simples e geral foi desenvolvido para a síntese de selenetos e teluretos vinílicos a partir de alquinos terminais e dicalcogenetos de diorganoíla usando NaBH4 e [bmim]BF4 como solvente reciclável. Este método eficiente permite a formação preferencial de calcogenetos vinílicos de configuração Z na maioria dos exemplos estudados. Também foi observado que na reação envolvendo fenilacetileno, (E)-bis-fenilcalcogenoestirenos foram obtidos com bons rendimentos e alta seletividade. O líquido iônico foi reutilizado três vezes sem perda da eficiência.

A general and simple method for the synthesis of vinyl selenides and tellurides starting from terminal alkynes and diorganyl chalcogenides using NaBH4 and [bmim]BF4 as a recyclable solvent was developed. This efficient and improved method furnishes the corresponding vinyl chalcogenides preferentially with Z configuration. We also observed that when the same protocol was applied to phenyl acetylene, (E)-bis-phenylchalcogeno styrenes were obtained in good yields and high selectivity. The ionic liquid was reused up three times without lost of efficiency.

Um método simples e eficiente foi desenvolvido para a hidrotiolação de fenilselenoalquinos utilizando KF/Al2O3 em meio livre de solvente. O método é geral e permite a preparação seletiva de (Z)-1-fenilseleno-2-organotio-1-alquenos a partir de tióis aromáticos e alifáticos em rendimentos de razoáveis a bons. A presença do grupamento organosselênio direcionou a regioquímica da adição do tiol. O sistema catalítico pode ser reutilizado mais quatro vezes sem tratamento prévio

We present herein the results of a simple and efficient protocol for the hydrothiolation of phenylselenoalkynes promoted by KF/Al2O3 using solvent-free conditions. This improved method furnishes selectively the corresponding (Z)-1-phenylseleno-2-organylthio-1-alkenes in reasonable to good yields starting from selenoalkynes and aliphatic or aromatic thiols. The presence of the phenylselenium group in the alkyne directed the regiochemistry of the thiol addition. The catalytic system can be reused up to 4 times without previous treatment.

Um método eficiente, limpo, quimiosseletivo e sem a utilização de solventes para a síntese de dimetil acetais de aldeídos e cetonas foi desenvolvido usando ortoformiato de trimetila e CeCl3 anidro como catalisador. O método é geral e, sob condições reacionais brandas, fornece compostos carbonílicos protegidos em bons rendimentos, incluindo aril e alquil cetonas e aldeídos. O catalisador pode ser reutilizado diretamente, três vezes, sem perda significativa da atividade.

An efficient, clean, chemoselective and solvent-free method for the synthesis of ketone and aldehyde dimethyl acetals was developed using trimethyl orthoformate and commercially available anhydrous CeCl3 as a recyclable catalyst. The method is general and affords the protected carbonyl compounds in good yields and under mild conditions, including aryl and alkyl ketones and activated aldehydes. The catalyst could be utilised directly for 3 cycles, without significant loss of activity.

Um método simples e eficiente foi desenvolvido para a adição conjugada de tióis ao citral na presença de KF/Al2O3 em meio livre de solvente ou usando glicerina como solvente reciclável a temperatura ambiente. O método em meio livre de solvente foi aplicado com sucesso na reação direta do tiofenol com o óleo essencial de capim limão (Cymbopogon citratus), para fornecer diretamente 3,7-dimetil-3-(feniltio)oct-6-enal, um potencial agente bactericida. O método foi estendido a outros alcenos deficientes de elétrons com excelentes resultados. Para o método em meio livre de solvente, o uso de irradiação com microondas facilitou o procedimento e acelerou a reação. O sistema catalítico e a glicerina podem ser reutilizados até três vezes sem tratamento prévio, com atividade comparável.

A general, clean and easy method for the conjugated addition of thiols to citral promoted by KF/Al2O3 under solvent-free or using glycerin as recyclable solvent at room temperature is described. It was found that the solvent-free protocol is applicable to the direct reaction of thiophenol with the essential oil of lemon grass (Cymbopogon citratus) to afford directly 3,7-dimethyl-3-(phenylthio)oct-6-enal, a potential bactericide agent. The method was extended to other electron-poor alkenes with excellent results. For the solvent-free protocol, the use of microwave irradiation facilitated the procedure and accelerates the reaction. The catalytic system and glycerin can be reused up to three times without previous treatment with comparable activity.

Um método simples e eficiente foi desenvolvido para a hidrocalcogenação de alquinos contendo um aceptor de Michael (éster, cetona e nitrila) com ânions fenilcalcogenolatos gerados in situ a partir do respectivo dicalcogeneto de difenila (Se, Te, S), usando hidreto de boro e sódio suportado em alumina e meio livre de solvente. Este método é geral e permite a obtenção de ésteres, cetonas e nitrilas (Z)-beta-fenilcalcogeno-<FONT FACE=Symbol>a,b</FONT>-insaturados, com rendimentos e seletividade comparados aos obtidos quando se utiliza solvente orgânico e atmosfera inerte. O uso de irradiação de microondas facilitou o procedimento e acelerou a reação.

A simple, clean and efficient solvent-free protocol was developed for hydrochalcogenation of alkynes containing a Michael acceptor (ester, ketone and nitrile) with phenylchalcogenolate anions generated in situ from the respective diphenyl dichalcogenide (Se, Te, S), using alumina supported sodium borohydride. This efficient and improved method is general and furnishes the respective (Z)-beta-phenylchalcogeno-<FONT FACE=Symbol>a,b</FONT>-unsaturated esters, ketones and nitriles, in good yield and higher selectivity, compared with those that use organic solvent and inert atmosphere. The use of microwave (MW) irradiation facilitates the procedure and accelerates the reaction.

Foi desenvolvido um método simples e eficiente para a síntese de beta-estirenos alfa-fenilseleno-substituídos, através da reação do alfa-(fenilselenobenzil)fosfonato de dietila e NaH na presença de aldeídos. A reação destes produtos com n-BuLi e posterior captura do ânion com aldeídos ou DMF levou à formação, exclusivamente, de álcoois de configuração Z e aldeídos <FONT FACE=Symbol>a,b</FONT>-insaturados de configuração E, respectivamente. Além disto, a hidrólise dos selenetos na presença de TiCl4 levou à formação de alfa-arilacetofenonas em bons rendimentos.

A new and efficient method was developed to prepare alpha-phenylseleno-beta-substituted styrenes by reaction of diethyl alpha-phenylseleno benzylphosphonate with NaH and aldehydes. Selenium-lithium exchange by reaction with n-BuLi yielded the vinyl lithium species, which were captured with several electrophiles, like aldehydes and DMF, affording exclusively (Z)-allyl alcohols, and (E)-alpha-phenyl-alpha-beta-unsaturated aldehydes, respectively in good yields. The hydrolysis of the vinyl selenides in presence of TiCl4 allowed the corresponding alpha-aryl acetophenones.

Um método simples e eficiente foi desenvolvido para a síntese de alfa-fenilselenoacrilonitrilas e ésteres alfa-fenilseleno-alfa,beta-insaturados através, respectivamente, da reação one-pot de aldeídos com fenilselenoacetonitrila ou acetato de (fenilseleno)etila na presença de um catalisador em suporte sólido (KF/Al2O3), sem o uso de solvente.

A simple, clean and efficient method has been developed for the synthesis of alpha-phenylselenoacrylonitriles and alpha-phenylseleno-alpha,beta-unsaturated esters by a one-pot reaction of aldehydes with phenylselenoacetonitrile or ethyl(phenylseleno)acetate respectively, in the presence of a solid supported catalyst (KF/Al2O3), without any solvent.