5- -2,2-dimethyl Irradiation apparatus

Irradiation of a solution of dimethyl acetylenedicarboxylate in a 14-fold molar excess of molten naphthalene at 90 °C with UV light for four days in a quartz apparatus gave an 11 % yield of 1 1 adducts, among which the major product (34%) was dimethyl 3,4-benzo-tricyclo[3.3.0.0 ]octa-3,6-diene-6,7-dicarboxylate (14). ... 

A solution of 2.5 g (7.72 mmol) of ( )-2,5-di(p-anisyl)-2,5-dimethyl-3-hexene in 1 L of acetone was irradiated through Pyrex in an 450 W Hanovia apparatus for 20 h and concentrated under vacuum. The residual oil was separated by chromatography on a 148 x 27 cm silica gel column with hexane elution 100 mL fractions were collected. Fraction... 

A mixture of 250 mg 3,3-dimethyl-1,5,5-triphenyl-2-aza-l,4-pentadiene (0.80 mmol), 550 mg m-methoxyacetophenone (3.7 mmol) and 450 mL dry -BuOH was put into a quartz immersion well apparatus with a Pyrex filter. The solution was purged with argon for 1 h and was irradiated with a 400-W medium-pressure mercury arc lamp for 6 h. After completion of the irradiation, the solvent and the sensitizer were removed under reduced pressure, the residue was chromatographed with hexane/Et20 (99 1) as an eluent to afford 65.0 mg benzaldehyde, and 13.0 mg of cyclopropylimine as a colorless oil, in a yield of 5%. Further elution with Et20 yielded 25 mg of a highly polar material. Final elution with EtOH afforded 148 mg l,l-dimethyl-3,3-diphenyl-2-propenylamine, in a yield of 81%. 

Wavelength specificity. 2,3-Dimethylbutane refluxed from a blackened flask into the thimble of a Soxhlet apparatus with dropwise addition of tert-h xXy nitrite and irradiation with 405 nm light 2,3-dimethyl-2-nitrosobutane. Y 78%. - The use of wavelengths around 400 nm is essential for this reaction. F. e. s. A. Mad or and T. J. de Boer, R. 89, 159 (1970) dimeric nitroso compds., azo N,N -dioxides, s. ibid. 89, 151. 

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