Rhodium-Catalyzed Regioselective Synthesis of Isocoumarins through Benzothiadiazine-Fused Frameworks

Prashant B. Dalvi, Kuang Ling Lin, Manohar V. Kulkarni, Chung-Ming Sun*

*Corresponding author for this work

Research output: Contribution to journalArticle

10 Scopus citations


An unprecedented two-step, one-pot synthesis of benzimidazothiadiazine 5,5-dioxides is presented. Reaction condition based regioselectivity has been achieved where fused benzimidazo[1,2-b][1,2,4]thiadiazines are exclusively formed under thermal conditions, whereas benzimidazo[2,1-c][1,2,4]thiadiazines were created only under microwave irradiation. The salient features of this protocol include a regioselective sulfonylation of 2-aminobenzimidazole with o-halo sulfonyl chlorides followed by N-C bond formation. The acid forms of these fused regioisomers have been used to introduce novel guanidine-containing isocoumarin frameworks.

Original languageEnglish
Pages (from-to)3706-3709
Number of pages4
JournalOrganic Letters
Issue number15
StatePublished - 5 Aug 2016

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