Synthesis of arylnaphthoquinones and their reactions with o-substituted primary aromatic amines

Cycloaddition reaction of 2-aryl-1,4-benzoquinones 1a-d with a number of di fferent dienes namely 2,3-dimethylbutadiene; 1,4-diphenylbutadiene and anth racene yield 2-aryl-6,7-dimethyl-1,4-naphthoquinones 3a,b; 2,5,8-triphenyl- 1,4-naphthoquinone 4 and 2-aryl-1,4,9,10-tetrahydro-9,10-o-benzoanthracene- 1,4-dione 5 respectively. in addition, the cycloaddition reaction of 2-aryl -1,4-benzoquinones 1d,e with 2,3-dimethylbutadiene was also investigated to yield 2-aryl-5,8-dihydro-6,7-dimethyl-1,4-naphthohydroquinones 2a,b. Cyclo condensation reactions of Diels-Alder adducts 2b, 3b, 5a with ethylenediami ne; o-substituted primary aromatic amines gave, quinoxaline, phenazine, phe noxazine and phenothiazine heterocyclic derivatives (6-14).