¾ defined as the design, development, and application of chemical processes and products to reduce or eliminate the use and generation of substances hazardous to human health and the environment. This article summarizes the 12 principles of green chemistry, describing how they have been applied to the academic, industrial and research activities around the world.]]>

The alternative synthesis of 12 1,2,4-oxadiazoles using ultrasound irradiation from trichloroacetoamidoxime and acyl chlorides is reported. Seven of them are novel compounds. The 3-trichloromethyl-5alkyl(aryl)-1,2,4-oxadiazoles have been synthesised in better yields and shorter reaction times compared to the conventional method. This protocol can be applicable for preparation of 1,2,4-oxadiazoles containing aryl or alkyl groups attached at their C-5 side-chain.

The Biginelli reaction is a multicomponent reaction involving the condensation between an aldehyde, a β-ketoester, and urea or thiourea, in the presence of an acid catalyst, producing dihydropyrimidinones (DHPMs). Owing to their important pharmacological properties, the DHPMs have been studied by many authors. However, most of the methodologies used for the synthesis of these compounds require drastic reaction conditions. In the current study, we report an efficient and clean procedure for preparing DHPMs by the use of citric acid or tartaric acid as a promoter of the Biginelli synthesis in ethanol as solvent. In addition, we have evaluated the antioxidant capacity of the compounds synthesized by the 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay and the thiobarbituric acid-reactive species test. Two compounds presented antioxidant activity and also reduced lipid peroxidation at concentrations of 200 and 300 µM. In summary, we report an environmentally friendly procedure for the preparation of DHPMs and demonstrate the antioxidant capacity of some of the compounds.

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The aims of this research were: evaluate the chemical composition and the cytotoxicity of the Cuminum cyminum (cumin), Anethum graveolens (dill), Pimpinella anisum (anise) and Foeniculum vulgare (fennel) essential oils, as well as their antifungal activity in vitro against ten Candida spp. isolates. The chemical composition of the oils was analyzed by means of gas chromatography coupled with mass spectrometry (GC/MS). The cytotoxicity assays were performed, using the cell proliferation reagent WST-1 in L929 mouse fibroblasts (20x10 3 well -1 ). The determinate the Minimum Inhibitory Concentration (MIC), was performed through the Broth Microdilution technique (CLSI). The chemical main components were the cuminaldehyde (32.66%) for cumin, carvone (34.89%) for the dill, trans-anethole (94.01%) for the anise and anethole (79.62%) for the fennel. Anise and fennel did not were cytotoxic in all the tested concentrations, however the cumin oil was cytotoxic in the concentration of 20 mg.mL -1 and the dill in the concentrations of 20 and 8 mg.mL -1 . All yeasts were susceptible against the evaluated essential oils. Cumin presented the lowest MIC against yeasts. We concluded that all the essential oils presented inhibitory action against Candida spp., and C. cyminum, P. anisum and F. vulgare were not cytotoxic in the same minimum inhibitory concentrations for the fungi. Composição química de óleos essenciais da família apiaceae, citotoxicidade e sua atividade antifúngica in vitro contra espécies de candida da cavidade oral ResumoOs objetivos desta pesquisa foram: avaliar a composição química e a citotoxicidade dos óleos essenciais de Cuminum cyminum (cominho), Anethum graveolens (endro), Pimpinella anisum (erva-doce) e Foeniculum vulgare (funcho), bem como sua atividade antifúngica in vitro contra dez isolados de Candida spp.. A composição química dos óleos foi analisada por meio de cromatografia gasosa acoplada à espectrometria de massa (GC / MS). Os ensaios de citotoxicidade foram realizados, utilizando o reagente de proliferação celular WST-1 em fibroblastos de ratinho L929 (20x103 poço-1). A determinação da Concentração Inibitória Mínima (MIC) foi realizada através da técnica de microdiluição em caldo (CLSI). Os principais componentes químicos foram o cuminaldeído (32.66%) para cominho, carvona (34.89%) para o endro, trans-anetol (94.01%) para erva-doce e anetol (79.62%) para a funcho. O endro e a erva-doce não foram citotóxicos em todas as concentrações testadas, no entanto, o óleo de cominho foi citotóxico na concentração de 20 mg.mL -1 e o endro nas concentrações de 20 e 8 mg.mL -1 . Todas as leveduras foram suscetíveis aos óleos essenciais avaliados. O cominho apresentou a menor CIM contra as leveduras. Concluímos que todos os óleos essenciais apresentaram ação inibidora contra Candida spp., e C. cyminum, P. anisum e F. vulgare não foram citotóxicos nas mesmas concentrações inibitórias mínimas para os fungos.Palavras-chave: Cuminum cyminum, Candidíase atrófica crônica, Candida spp., antifúngico.

A series of twelve 5-bromo[5,5-dibromo]-4-methoxy-1,1,1-trihalo-3-alken-2-ones 5a-d, 6a-d, 7a, 9a, 10a and 6-bromo-5-methoxy-1,1,1,2,2-pentafluoro-4-hexen-2-one (8a) were synthesized in high purity and good yields (70-95%) by the regiospecific allylic bromination of 4-methoxy-1,1,1-trihalo-3-alken-2-ones 1ad, 2a-d, 3a or 5-methoxy-1,1,1,2,2-pentafluoro-4-hexen-2-one (4a), respectively, with bromine followed by addition of pyridine. The usefulness of compounds 5-10 in heterocyclic synthesis is also reported.

A one‐pot synthesis of 1‐methyl‐ and 1‐phenylpyrazole‐3(5)‐ethyl esters 2,3a‐e by the cyclocondensation of β‐alkoxyvinyl trichloromethyl ketones 1a‐e with methyl and phenyl hydrazine hydrochloride under mild conditions, is reported. A study using compounds 1a‐e with different substituents proved that these are versatile building blocks for the synthesis of pyrazole derivatives, having a 3(5)‐ethoxycarbonyl substituent in good yields (60–89%). The hydrazine and β‐alkoxyvinyl trichloromethyl ketone substituent effects on the reaction regiochemistry on the formation of the 1,3‐ and 1,5‐isomer were observed.

An ultrasound-enhanced method has been developed for the synthesis of a variety of thioesters from benzoyl chlorides and 2-mercaptobenzoxa(thia)zoles. Applying this methodology, 14 compounds were synthesized in excellent yields.