Authors: Castro, A.A.; De Souza, M.V.N.; Rey, N.A.; Farias, P.A.M.
Source: Journal of the Brazilian Chemical Society (Impresso), v. 22, p. 1662-1668, 2011.
Publisher: Brazilian Chemical Society
Abstract
A stripping method for the determination of the antiretroviral drug efavirenz at the submicromolar concentration levels in diluted alkaline electrolyte is described. Optimum experimental conditions were: 2.0 × 10-3 mol L-1 NaOH, accumulation potential of -0.10 V, pulse amplitude of 50 mV and scan rate of 50 mV s-1. The response is linear over the concentration range of 0.01-0.25 ppm. For an accumulation time of 10 min, the limit of detection was 1.0 ppb (3.0 × 10-9 mol L-1). The most convenient conditions to measure the efavirenz concentration in the presence of ATP, DNA, several metals, and other antiviral drugs was also investigated. The utility of the method is demonstrated by the determination of efavirenz in a synthetic mixture containing both lamivudine and zidovudine, which are frequently used in the clinic in association with efavirenz as part of highly active antiretroviral therapy (HAART).Keywords: efavirenz determination, antiviral drugs, metals, thin-film mercury electrode, differential pulse scan stripping voltammetry Document Type: Research Article DOI: http://dx.doi.org/10.1590/S0103-50532011000900007 Publication date: 1 de Setembro de 2011
Authors: Pinheiro, Alessandra C.; Kaiser, Carlos R.; LourenÇo, Maria C.S.; de Souza, Marcus V.N.; Wardell, Solange M.S.V.; Wardell, James L.
Source: Journal of Chemical Research, Volume 2007, Number 3, 1 March 2007, pp. 180-184(5)
Publisher: Science Reviews 2000 Ltd
Abstract
Reactions between either L-serine methyl ester hydrochloride (1), or the cbz derivative, methyl (S)-(+)-2-(benzyloxycarbonylamino)-3-hydroxypropanoate (2), and pyrazinoyl chloride (3), have been studied. Methyl (S)-(+)-2-benzyloxycarbonylamino-3-[(pyrazinecarbonyl)oxy]propionate (4), methyl (S)-(+)-3-hydroxy-2-[(pyrazine-2-carbonyl)amino]propionoate (7), methyl 2-[(pyrazinecarbonyl)amino]acrylate (8) were obtained. Additional products, methyl (S)-(+)-2-benzyloxycarbonylamino-3-formyloxypropionoate (5) and methyl (R)-(+)-2-benzyloxycarbonylamino-3-chloropropionoate (6), were isolated from reaction of 2 with 3, in the presence of DMF remaining from the preparation of 3, from pyrazinecarboxylic acid. The coupling of pyrazinecarboxylic acid with 1, in the presence of DCC was prevented by the formation of the unreactive adduct between DCC and pyrazinoic acid. The compounds were tested against M. tuberculosis: compounds (8) and (6) exhibited a MIC (μg/ml) value of 50 and 100, respectively, compared to the MIC value of 100 for the first line TB drug, pyrazinamide. The confirmation of the structure of (8) was obtained via X-ray crystallography.Keywords: SYNTHESIS, TUBERCULOSIS, L-SERINE DERIVATIVES, PYRAZINOIC ACID DERIVATIVES, CRYSTAL STRUCTURE, DIDEHYDROAMINO ACID Document Type: Research Article DOI: http://dx.doi.org/10.3184/030823407X200001 Publication date: 1 de Março de 2007
