Juliano C. R. Freitas

Allylation of Functionalized Aldehydes by Potassium Allyltrifluoroborate Catalyzed by 18-Crown-6 in Aqueous Media

An efficient method for the allylation of aldehydes containing a broad range of functional groups using potassium allyltrifluoroborate is described. The reaction utilizes a catalytic amount of 18-C-6 in biphasic media under open atmosphere and room temperature to provide the corresponding homoallylic alcohols in high yields and without the necessity of any subsequent purification.

Metal free synthesis of homoallylic alcohols promoted by ultrasound

The use of ultrasound irradiation to promote the allylation of aldehydes containing different functionalities with potassium allyltrifluoroborates is described. The method features the use of a minimum amount of acetone as solvent, without any other catalyst or promoter. The products were obtained in high yields, short reaction times, at room temperature and without the need of further purification.

A CONVENIENT SYNTHESIS AND CYTOTOXIC ACTIVITY OF 3-ARYL-5-PENTYL-1,2,4-OXADIAZOLES FROM CARBOXYLIC ACID ESTERS AND ARYLAMIDOXIMES UNDER SOLVENT-FREE CONDITIONS

The synthesis of 3-aryl-5-pentyl-1,2,4-oxadiazoles from carboxylic acid esters and arylamidoximes in the presence of potassium carbonate is described. The reaction was carried out in a microwave oven without any solvent in much shorter time and in good yields. The structures of the synthesized compounds were elucidated using IR, 1H and 13C NMR spectroscopy and elemental analysis and their antiproliferative activities was evaluated against three different human cell lines.

D‐Glucose, a Fascinating Biomolecule: History, Properties, Production and Application

Os carboidratos sao as biomoleculas mais abundantes na Terra e anualmente sao produzidos aproximadamente 200 bilhoes de toneladas desses compostos pelas plantas superiores e algas.Dentre os inumeros compostos classificados como carboidratos, a D-glicose e de longe o monossacarideo mais abundante. AD-glicose e um dos poucos carboidratos de baixa massa molecular, economicamente atrativo, produzido em larga escala e propenso a modificacoes estruturais para a producao de novos compostos.A D-glicose e utilizada nos mais variados setores industriais, tais como: no alimenticio, farmaceutico, cosmetico, quimico dentre outros. Diante disto, e justificavel o aumento anual da demanda de D-glicose, na qual ela pode ser obtida por distintos processos industriais, como a hidrolise acida e a hidrolise enzimatica.Em funcao da relevância da D-glicose, este artigo apresenta uma revisao sobre a historia, as propriedades, a producao e biossintese deste composto.

Recent Advances in C-Glycoside Chemistry: Application, Synthesis and Reactions

A sintese de C-glicosideos, analogos de acucar em que o oxigenio glicosidico e substituido por um atomo de carbono e de particular interesse devido a sua utilidade como intermediarios chave para a montagem de moleculas e produtos naturais biologicamente ativos. Apesar da sua quimica desafiadora, devido a sua versatilidade, os C-glicosideos desempenham um papel fundamental no desenvolvimento da quimica de novos materiais e moleculas bioativas. Nesta revisao, apresentamos varias metodologias sinteticas, proposta mecanicista e aplicacao de C-glicosideos 2,3-insaturados nos ultimos vinte ano

An Efficient Method for the Hydrolysis of Potassium Organotrifluoroborates Promoted by Montmorillonite K10

An efficient and non-expensive method for conversion of diverse potassium organotrifluoroborates to their corresponding boronic acids promoted by montmorillonite K10 using water as the reaction solvent is described. Further interconversion of potassium organotrifluoroborates to their corresponding boronic esters, via boronic acid intermediates was also successfully accomplished. The products were obtained in good yields, being the rate of hydrolysis influenced by the type of substituent present in the boronic acid.

Separação de Mistura Sólido–Sólido : Novo Enfoque Experimental

Neste artigo, um novo metodo experimental e apresentado na separacao de mistura solido-solido, usando materiais baratos e simples. As atividades propostas foram divididas em dois momentos distintos: a) construcao de equipamentos; b) realizacao de experimentos para gerar resultados a serem interpretados. Estas atividades possibilitam a construcao de conceitos, por exemplos, solubilidade, substâncias, misturas, dissolucao, combustao e inflamavel.