437-69-4Relevant academic research and scientific papers
Synthesis and antifungal evaluation of hydroxy-3-phenyl-2H-1,3-benzoxazine- 2,4(3H)-diones and their thioanalogs
Skala, Pavel,Machacek, Milos,Vejsova, Marcela,Kubicova, Lenka,Kunes, Jiri,Waisser, Karel
experimental part, p. 873 - 880 (2009/12/26)
(Chemical Equation Presented) A series of substituted 5-, 6-, 7-, and 8-hydroxy-3-phenyl-2H-1,3-benzoxazine-2,4(3H)-diones (5-8) was synthesized by cyclization of corresponding dihydroxy-N-phenylbenzamides (1-4) with methyl chloroformate. The starting compounds 1-4 were prepared by the reaction of the respective dihydroxybenzoic acid, aniline and phosphorus trichloride via microwave irradiation. Thionation of compounds 8a-d employing Lawesson's reagent was used to prepare 5-hydroxy-3-phenyl-4-thioxo-3,4-dihydro-2H-1,3-benzoxazin- 2-ones (10a-d) and 5-hydroxy-3-phenyl-2H-1,3-benzoxazine-2,4(3H)-dithiones (11a-d). The position of sulfur in monothionated derivatives 9c and 10a-d was confirmed by 2D NMR methods. Attempts to prepare dithionated derivatives from the isomeric 6-, 7- or 8-hydroxy compounds 5-7 failed. All compounds were tested for their in vitro antifungal activity against eight test strains. Compounds 1-4 showed moderate activity and the cyclization to corresponding hydroxy-3-phenyl-2H-1,3-benzoxazine-2,4(3H)-diones (5-8) resulted in a decrease in antifungal activity. No antifungal activity was observed in thionated compounds 9c and 10-11.
