Síntese de análogos de fitoalexinas com base de Benzoxazol como potenciais agentes antibacterianos e antifúngicos

Abstract

In the search for new means of plant defense and alternative methods for the control pathogens was prepared 2-Benzoxazolinone, 5-nitrobenzoxazolinone and Arylhydrazone 2- benzoxazolinone representing the synthetic phytoalexins analogues with possible activity antibacterial and antifungal. The method chosen consists of the reaction of ortho-aminophenols replaced with urea in the middle of organic solvents under reflux. Initially, 2-benzoxazolinone was synthesized, which consisted of a mixture of 50 mmol of urea and 50 mmol of o-aminophenol using toluene solvent, in a reaction flask 50 mL. Subsequently, another synthesis was carried out, 5-nitrobenzoxazolinone, which consisted of mixture of 10 mmol of urea and 10 mmol of 2-amino-5-nitrophenol with the use of n- butanol in a 50 ml reaction flask. Then, the synthesis of Arylhydrazone 2- benzoxazolinone, which consisted of a 10mmol mixture of 2-benzoxazolinone synthesized in first experiment, 10 mmol of phenylhydrazine hydrochloride and 12 mmol of hydrogen carbonate sodium using ethanol solvent in a 50 mL reaction flask. The following reactions in electric blankets with heating of the reagents in the presence of each solvent mentioned above at 105oC, adding boiling stones to each reaction flask. The time reaction time was 62 hours for 2-benzoxazolinone synthesis, 78 hours for 5- nitrobenzoxazolinone and 28 hours for arylhydrazone synthesis of 2-benzoxazolinone, with gross yields on the order of 79.59% to 91.3% and purified on the order of 66.5% to 73.6%. O range of melting temperatures of the compounds purified by recrystallization was of the order of 3-4oC. The course of the first two reactions was accompanied by the release of ammonia, detected by the pH indicator paper and the last one using Layer Chromatography Slender. Finally, the analysis of the purified product synthesized 2-Benzoxazolinone was carried out in Infrared spectroscopy to determine its chemical composition. THE confirmation of the structure of 2-benzoxazolinone was made with the aid of spectroscopy of Infrared, measurement of its melting point and subsequent comparison with the spectrum and point of standard 2-benzoxazolinone fusion.