Application of the Gould–Jacobs reaction to 4-amino-2,1,3-benzoselenadiazole

An effective method for the synthesis of 4-amino-2,1,3-benzoselenadiazole ( 4) has been described. Reduction of readily available 4-nitrobenzothiadiazole 6 with SnCl 2·2H 2O afforded 1,2,3-triaminobenzene dihydrochloride 2. The latter upon treatment with aqueous SeO 2 solution provided desired amine 4. Nucleophilic vinylic substitution of activated enol ethers 7 with amine 4 led to (benzoselenadiazol-4-ylamino)methylene derivatives 8. Thermal cyclization of derivatives 8a– c, e, f under Gould–Jacobs reaction conditions gave angularly annelated 7-(non)substituted selenadiazolo[3,4- h]quinolones 9. Acid hydrolysis of etyl ester 9c afforded corresponding acid 10. All prepared selenadiazoloquinolones were tested for antimicrobial activity. [Display omitted]