O presente trabalho descreve as atividades antibacterianas e antifúngicas de diversas chalconas obtidas diretamente através da condensação aldólica tipo Claisen-Schmidt das quais se determinou a concentração inibitória mínima frente a diferentes microrganismos (bactérias Gram-positivas e Gram-negativas e fungos). Estruturas no estado sólido cristalino de sete chalconas foram determinadas por análise de difração de raios X (XRD). Estudos quimiométricos foram realizados com intuito de identificar uma potencial relação entre estrutura e atividade.

The present work describes the antibacterial and antifungal activities of several chalcones obtained by a straight Claisen-Schmidt aldol condensation determined by the minimal inhibitory concentration against different microorganisms (Gram-positive and Gram-negative bacteria and fungi). Solid state crystal structures of seven chalcones were determined by X-ray diffraction (XRD) analysis. Chemometric studies were carried out in order to identify a potential structure-activity relationship.

This article describes an undergraduate experiment for the synthesis of p-nitrophenyldiazonium chloride and its coupling with acetylacetone and two enaminones, 4-phenylamino-pent-3-en-2-one and 4-amino-pent-3-en-2-one, in an adaptation of a previously reported synthetic protocol. The azo dyes 4-(E)-phenylamino-3-[(E)-2-(4-nitrophenylazo)]-3-penten-2-one and 4-(E)-amino-3-[(E)-2-(4-nitrophenylazo)]-3-penten-2-one were obtained, and the solid state structure of this latter azo compound was characterized by single crystal X-ray diffraction studies. This two-week integrated laboratory approach involves simple synthetic experiments and microwave chemistry in the organic laboratory plus crystallography analysis, suitable for novice students on undergraduate experimental chemistry courses.

This study represents an integrated approach towards understanding the electronic and structural aspects of 2-benzylamino-1,4-naphthalenedione, a representative 2-amino-napfthoquinone. To this end, theoretical calculations performed at the B3PW91/6-31+G(d) level of density functional theory, electrochemical and X-ray structural investigation were employed. Two intramolecular H-bonds and other two intermolecular H-bonds were observed, including non-classical interactions. Cyclic voltammogram (CV) and differential pulse voltammetry (DPV) show two pairs of peaks, being each one a monoelectronic process.

Guanil-hidrazonas poli-substituídas foram sintetizadas através da reação de guanilação de tiossemicarbazonas com aminas aromáticas e alifáticas, promovida HgCl2. Este método representa o primeiro emprego de tiossemicarbazonas como componente eletrofílico em reações de síntese de guanidinas mediadas por tiófilo, onde a introdução de cada substituinte dos nitrogênios das guanil-hidrazonas ocorreu de forma regiosseletiva. As atividades antibacteriana e antifúngica foram avaliadas e alguns derivados mostraram atividade em valores pequenos de concentração inibitória mínima e com amplo espectro de atividade. Estudou-se a estrutura cristalina de duas guanil-hidrazonas, determinando-se suas configurações e, as únicas interações relevantes observadas foram intermoleculares do tipo N-H...N e C-H...N.

Thiosemicarbazones were employed for the first time as electrophiles in the guanylation reaction promoted by HgCl2, affording polysubstituted guanylhydrazones, with regioselective introduction of each nitrogen substituent. The antibacterial and antifungal activities of guanylhydrazones were evaluated by determination of minimal inhibitory concentrations. Some of them exhibited very low minimal inhibitory concentrations (MIC) and broad-spectrum activities. The configurations of two guanylhydrazones were assigned by X-ray analysis that also revealed intramolecular interactions of the type N-H...N and C-H...N.

A reação de enaminonas com o derivado metoximetilênico do ácido de Meldrum forneceu N-adutos e/ou C-adutos das enaminonas, em rendimentos moderados a bons. A regioquímica da reação se revelou dependente do substituinte do nitrogênio da enaminona, e o C-aduto formado é precursor para 2-piridonas. A análise da difração de raios X de dois N-adutos revelou que estes adutos possuem a configuração Z-s-Z.

The reaction of acyclic enaminones with methoxymethylene Meldrum's acid afforded N-adduct and/or C-adduct of enaminones in moderate to good yields. The regiochemistry of this reaction depends on the N-amino substituent of the enaminone. The C-adduct is a precursor to 2-pyridones. X-ray analysis of two N-adducts were investigated and the Z-s-Z configuration assigned.

Succinimido enaminonas foram sintetizadas através da reação de enaminonas e a N-(p-toluil)-maleimida em rendimento moderado a bom. A ação antibacteriana destes compostos contra E. coli e S. aureus foi avaliada, mas a atividade antibacteriana não foi significativa. A regioquímica das succinimido enaminonas foi racionalizada empregando-se a teoria dos orbitais moleculares de fronteira. A estrutura cristalina de um dos compostos foi determinada e foram observadas várias pontes de hidrogênio inter- e intramolecular do tipo NH...O e CH...O.

The reaction of N-(p-tolyl)-maleimide with enaminones afforded succinimide-containing enaminones in moderate to good yields, and these compounds were evaluated against E. coli and S. aureus, but no significant antibacterial activity was observed. The regiochemistry of the compounds was examined mechanistically within frontier molecular orbital considerations. In the solid state three-dimensional structure there is the formation of cooperative inter- and intramolecular NH...O and CH...O hydrogen bonding.