Author:
Collis Gavin E.,Wege Dieter
Abstract
Addition of 2-diazopropane to 1,4-naphthoquinone at low temperature, followed by in situ enolization and acetylation or silylation gave 3,3-dimethyl-1H-benz[f]indazol-4,9-diyl diacetate and 3,3-dimethyl-9-(t-butyl-dimethylsilyloxy)-1H-benz[f]indazol-4-ol, respectively. Functional group manipulation of the latter compound provided a number of other 4,9-disubstituted 3,3-dimethyl-3H-benz[f]indazoles. Irradiation of the diacetate led to clean extrusion of nitrogen to give the naphtho[b]cycloproparene and an alkene. Attempts to elaborate the cycloproparene into the derived cyclopropanaphthoquinone were unsuccessful. Of the other 4,9-disubstituted 3,3-dimethyl-3H-benz[f]indazoles examined, only the compound possessing an acetoxy group at C9 was photoactive, and afforded the expected cycloproparene and alkene. Compounds bearing a hydroxy or alkoxy group at C9 were photochemically inert.
Cited by
3 articles.
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