Synthesis of bis-Isoxazolilnaphthoquinones

C. S. ORTIZ, M. R. LONGHI, M. M. DE BERTORELLO Y M. C. BRIÑÓN

ROUTLEDGE JOURNALS, TAYLOR & FRANCIS LTD

Año: 1991 p. 181 - 181

revious results from our laboratory have that sodium 1,2-naphthoquinone-4-sulfonate (1) reacts with methyl substituted aminoisoxazoles (2) in aqueous solutions to give 4-(aminoisoxazolyl)-1,2-naphtoquinones (3) and 2-hydroxy-N-isoxazolyl-1,4-nathoquinone-4-imines (4) as the major products, along with low yields of bis-isoxazolylnaphthoquinone (5). These compounds show trypanocidal activity against T. cruzi both in vitro and in vivo. Based on these findings and the widely know biological activity of many naphthoquinone and isoxazole derivatives, we decided to focus our synthetic efforts towards compounds 5a-e which represent a relatively unexplored class of naphthoquinones with an important potential biological function. Extensive studies of the medium, time and temperature effects on the course of these reactions allowed us to select the best reaction conditions to direct the synthesis towards the formation of 5. This paper reports an improved synthetic procedure for the previously re