Photochemistry of α-diketones. III. Some photochemical reactions of 1,1,4.4-Tetramethyl-2,3-dioxotetralin in carbon tetrachloride

Abstract

Irradiation (at λ > 3000 Ǻ) of 1,1,4,4-tetramethyl-2,3-dioxotetralin (I) in carbon tetrachloride under nitrogen gave 1,1,3,3- tetramethylindanone (III) (0.5%), 2-hydroxy-1,1,4,4-tetramethyl-3- oxotetralin (II) (21%), 2-hydroxy-1,1,4,4-tetramethyl-3-oxo-2- trichloromethyltetralin (IV) (14%), the cyclic unsaturated carbonate (VII) (7%), and 1-carboxymethyl-1,3,3-trimethylindanone (XII) (15%). When an atmosphere of oxygen was used the products were very different: of the above-mentioned compounds, only (III) (9%) was isolated. Other compounds isolated were α,α?-o-phenylenediisobutyric anhydride (XIV) (16%), the peroxy acid lactone (XIII) (5%), the lactone (XV) (16%), α,α?-o-phenylenediisobutyric acid (XVI) (6%), and α-(o- isopropenyl)phenylisobutyric acid (XVII) (trace). This composition closely paralleled that obtained when benzene was used as solvent for the photooxidation.