Erika Martins de Carvalho

Synthesis and antitubercular activity of novel Schiff bases derived from D-mannitol

Six Schiff base derivatives of d-mannitol, 1,6-dideoxy-1,6-bis-{[(E)-arylmethylidene]amino}-d-mannitol (6: aryl=XC(6)H(4): X=o-, m- and p- Cl or NO(2)), have been synthesized and evaluated for their in vitro antibacterial activity against Mycobacterium tuberculosis H(37)Rv using the Alamar Blue susceptibility test and the activity expressed as the minimum inhibitory concentration (MIC) in microg/mL. All three nitro derivatives exhibit significant activities: activities of (6d: X=o-NO(2)), (6e: X=m-NO(2)) and (6f: X=p-NO(2)) are 12.5, 25.0 and 25.0microg/mL, respectively. When compared with first line drugs, such as ethambutol, they can be considered as a good starting point to develop new lead compounds for the treatment of multidrug-resistant tuberculosis. Characterization of the new compounds 6 is generally achieved spectroscopically. The structure of compound 3 has been confirmed by X-ray crystallography.

Síntese de aminoálcoois derivados do D-manitol

Aminoalcohols have found important applications in synthetic and medicinal chemistry, being used as chiral building blocks for the synthesis of many biologically active compounds. This class of compounds has been also used as chiral auxiliaries and ligands in asymmetric synthesis. Due to the importance of aminoalcohols in the treatment of several diseases, such as tuberculosis, the aim of this article is the synthesis and preliminary evaluation against tuberculosis of six aminoalcohols in 5 or 6 steps using D-mannitol as starting material, which is a useful carbohydrate employed in many syntheses.

Comparison of the reactivities of 2-mercaptoaniline and 2-hydroxyaniline with 2-chloronicotinoyl chloride

The reaction between equimolar 2-chloronicotinoyl chloride and 2-mercaptopyridine in ClCH2CH2Cl, after 30 minutes refluxing in ClCH2CH2Cl solution, produced pyrido[2,3,b][1,5]benzothiazepin-5(H)one 7, and 6-[3-(2-benzothiazolyl)pyridin-2-yl)thio]-N-[3-(2-benzothiazolyl)pyridin-2-yl]aniline 8. In contrast, the reaction using the same reaction conditions between equimolar 2-chloronico- tinoyl chloride and 2-hydroxypyridine, produced the simple amide, 2-chloro-N-(2-hydroxyphenyl) nicotinamide 9. 2-Chloro-N-(2-mercaptophenyl)nicotinamide was considered to be a common intermediate in the formation of 7 and 8. The characterizations of 7–9 were achieved by X-ray crystallography. The conformations of 7 and 8 in the solid state can be described as “U” and “V”-shaped, respectively.

Solution and Solid State Nuclear Magnetic Resonance Spectroscopic Characterization of Efavirenz

Samples of efavirenz (EFZ) were evaluated to investigate the influence of the micronization process on EFZ stability. A combination of X-ray diffraction, thermal analysis, FTIR, observations of isotropic chemical shifts of (1)H in distinct solvents, their temperature dependence and spin-lattice relaxation time constants (T1), solution (1D and 2D) (13)C nuclear magnetic resonance (NMR), and solid-state (13)C NMR (CPMAS NMR) provides valuable structural information and structural elucidation of micronized EFZ and heptane-recrystallized polymorphs (EFZ/HEPT). This study revealed that the micronization process did not affect the EFZ crystalline structure. It was observed that the structure of EFZ/HEPT is in the same form as that obtained from ethyl acetate/hexane, as shown in the literature. A comparison of the solid-state NMR spectra revealed discrepancies regarding the assignments of some carbons published in the literature that have been resolved.

Aspectos populares e científicos do uso de espécies de Eugenia como fitoterápico

The use of the Brazilian biodiversity by the population remains a major source of discovery of new bioactive chemical entities. In this work a literature review is carried out relative to botany characteristics, ethnobotany, pharmacological activity, toxicological and chemical composition of Eugenia species: Eugenia brasiliensis Lam, Eugenia dysenterica DC, Eugenia umbelliflora O. Berg, Eugenia florida DC., Eugenia involucrate DC. and Eugenia uniflora L. This retrospective descriptive study aims to evaluate the biopotential of the species belonging to this gender as well as the advancement in the development of the phytomedicines using these plants.