Nitration of 5,6,7,8‐tetrahydro‐5,8‐methanoisoquinoline N ‐oxide with other aromatic substitutions. Isolation and mutagenicity of an α‐nitropyridine N ‐oxide

Treatment of 5,6,7,8‐tetrahydro‐5,8‐methanoisoquinoline N ‐oxide ( 2 ) with fuming nitric acid afforded 3‐nitro‐5,6,7,8‐tetrahydro‐5,8‐methanoisoquinoline N ‐oxide ( 3 ), an example of formation of an α‐nitropyridine N ‐oxide derivative by nitration of N ‐oxides. Further reaction of 3 resulted in deoxygenation giving 3‐nitro‐5,6,7,8‐tetrahydro‐5,8‐methanoisoquinoline ( 4 ). No aromatic nitration was observed by similar treatment of 5,6,7,8‐tetrahydro‐5,8‐methanoisoquinoline ( 1 ) or 5,6,7,8‐tetrahydroisoquinoline N ‐oxide ( 11 ). Some other aromatic substitutions with 1 and 2 were caried out to obtain mainly the 3‐substituted derivatives. Significant mutagenicity of 3 is briefly reported.