Synthesis and chemical transformation of fused tetrazoles derived from 2-bromomethyl- and 2-iodomethyl-3,5,6,7-tetrahydro-4(2H)-benzofuranones

✍ Scribed by Malose J. Mphahlele; Thwanthwadi B. Moekwa

• Book ID: 102346765
• Publisher: Journal of Heterocyclic Chemistry
• Year: 2006
• Tongue: English
• Weight: 132 KB
• Volume: 43
• Category: Article
• ISSN: 0022-152X
• DOI: 10.1002/jhet.5570430414

✦ Synopsis

Abstract

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The 2‐bromomethyl‐3,5,6,7‐tetrahydrobenzofuranones 1a‐d were subjected to triazidochlorosilanesodium azide‐mediated Schmidt rearrangement to afford the corresponding tetrazolofuroazepine derivatives 2a‐d via methylene shift. Under similar reaction conditions, the 2‐iodomethyl‐3,5,6,7‐tetrahydrobenzofuranones 1e‐h afford mixtures of the corresponding tetrazolofuroazepines 2e‐h and the 4‐azido‐2‐iodomethyl‐2,3‐dihydrobenzofuran derivatives 3a‐c. A mechanism is proposed to account for the divergence in the reactivity of these 2‐halogenomethyltetrahydrobenzofuranones (X = Br versus I). In turn, the 2‐halogenomethyltetrazolofuroazepines 2a,b,d‐h and the 4‐azido‐2‐iodomethyl‐2,3‐dihydrobenzofurans 3a,b underwent nucleophilic substitution with triethyl phosphite and dehydrohalogenation using DBU in refluxing toluene to give the corresponding tetrazolofuroazepines 4a‐d and 5a‐c and benzofurans 6a,b.