
%0 Journal Article
%A Collis, Gavin E. 
%A Wege, Dieter 
%T Approaches to Cyclopropa-Fused Quinones. The Synthesis and Photolysis of Some 4,9-Disubstituted 3,3-Dimethyl-3<emph type="2">H</emph>-benz[<emph type="2">f</emph>]indazoles
%J Australian Journal of Chemistry
%D 2003/08/08
%V 56
%N 9
%P 903-908
%K 
%R https://doi.org/10.1071/CH03060
%U https://www.publish.csiro.au/paper/CH03060 
%X 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. 
