Cyclization of nitrospirobenzopyrans to bridged benzoxazepino[3,2-a]indoles

Summary, in English

Condensation of 1-substituted 1,2,3,9a-tetrahydro-9H-imidazo[1,2-a]indol-2-ones with 5-nitrosalicylaldehyde afforded 1'-[(N-monosubstituted carbamoyl)methyl]indoline nitrospirobenzopyrans. Treatment of the latter with strong base led to the formation of a mixture of cis/trans-5a,13-methano-1,3-benzoxazepino[3,2-a]indoles. Results of semiempirical calculations gave evidence that such a transformation of nitrospirobenzopyrans to bicyclic indole derivatives could proceed via a single transition state, where the negatively charged carbon atom attacks the vinylic double bond of the spiropyran system.

• Author: Neringa Kleiziene; Virgine Amankaviciene; Ulf Berg; Carsten Schicktanz; Klaus Schlothauer; Algirdas Sackus
• Department/s: Centre for Analysis and Synthesis
• Publishing year: 2006
• Language: English
• Pages: 1109-1117
• Publication/Series: Monatshefte fur Chemie
• Volume: 137
• Issue: 8
• Links: http://dx.doi.org/10.1007/s00706-005-0504-7
• Document type: Journal article
• Publisher: Springer
• Topic: Organic Chemistry
• Keywords: carbanions; nitrospiropyrans; heterocycles; indoles; 5a; 13-methano-1; 3-benzoxazepino[3; 2-a]indoles
• Status: Published
• ISBN/ISSN/Other: ISSN: 1434-4475