A variety of electrophiles (anhydrides, acid chlorides, carbonochloridates, sulfonyl chlorides, and alkyl bromides) react with 3-methoxy-2H-indazole (1a), benzoxazin[3,2-b]indazole (1d), and oxazolino[3,2-b]indazole (1e) - substrates available by the Davis-Beirut reaction - to yield a diverse set of N(1),N(2)-disubstituted-1H-indazolones. With certain electrophiles, an AERORC (Addition of the Electrophile, Ring Opening, and Ring Closure) process on indazole 1d results in indazoloindazolone formation. An intriguing aspect of these N(1),N(2)-disubstituted-1H-indazolones is that they are poised for diversification through, for example, azide-alkyne cycloaddition chemistry reported here.
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