Application of 9-ethyl[1,2,5]selenadiazolo[3,4-h]quinolones in the synthesis of tricyclic azoloquinolones

A series of tricyclic azoloquinolones was prepared by a novel approach based on the protection of a benzene-1,2-diamine moiety as 2,1,3-benzoselenadiazole ring. A new reductive deselenation of 9-ethylselenadiazolo[3,4-h]quinolones using zinc powder in acetic acid afforded 7,8-diamino-1-ethylquinolones in high yields. The obtained diaminoquinolones were employed as useful substrates in cyclocondensation reactions leading to azoloquinolone derivatives.

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