Irradiation with sodium vapor lamp

Singlet oxygen is generated by irradiation of oxygen with two 1000-W sodium-vapor lamps using tetraphenylporphine as photosensitizer. After 5 h, the reaetion is eom-plete and triphenylphosphine is added until die peroxide test is negative. Then [5c,d] ean be isolated by flash ehromatography. 

A mixture of 4 g of diazoketone (94) and 2.2 g of sodium bicarbonate in 200 ml of tetrahydrofuran and 180 ml of water is irradiated with a Hanovia 200 W mercury vapor lamp (using a Corex filter) until the starting material has been consumed. After addition of 500 ml of water, followed by extraction of nonacidic products, the solution is acidified, cooled to 0° and filtered to yield 2.95 g (76%) of white crystals of crude acid (95) mp 170-176°. An analytical sample has mp 188°. ° ... 

Photolytic. Plimmer and Hummer (1969) studied the irradiation of chloramben in water (2-4 mg/L) under a 450-W mercury vapor lamp (7, >2,800 A) for 2-20 h. Chloride ion was released and a complex mixture of colored products was observed. It was postulated that amino free radicals reacted with each other via polymerization and oxidation processes. The experiment was repeated except the solution contained sodium bisulfite as an inhibitor under a nitrogen atmosphere. Oxidation did not occur and loss of the 2-chloro substituent gave 3-amino-5-chlorobenzoic acid (Plimmer and Hummer, 1969). 

Photoreduction. Irradiation of 3,17/i-cstradiol (1) with a Hanovia mercury vapor lamp in an aqueous ethanol solution containing sodium sulfite gives as the major product 3/J,17/3-dihydroxy-5a,10)3-estrane (2). Reduction in the presence of sodium borohydride gives (3) and (4) in low yield.1 Tt is suggested that the reduction with sodium sulfite may proceed through a sulfinate intermediate. This novel photoreduction method was first observed with kynurenic acid (5), which is reduced in this way to kynurenine yellow (6).2... 

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