Photodimerization of Uracil Sensitized by Acetone

Abstract

100 ml of pure CS2 at room temperature. The clear yellow solution, obtained by filtration from insoluble polymer, is acetone provides a further, mild method of specifically altering nucleic acids by photochemical methods. concentrated to 20 ml in a vacuum and then cooled at -3OOC for 12 h. The mother liquor is decanted from precipitated sulfur, and the latter is treated dropwise, with careful shaking, with sufficient pure CS2 (ca. 10 ml) to dissolve all the yellow s8 and leave behind only the characteristic four-cornered platelets of S12. After decantation of the solution, these platelets are washed with 1 ml of CS2 and the remaining suspension of crystals is finally dried on filter paper. In this way 20 mg of S12 ("yield" ca. 0.1 %) of Slz is isolated, having m.p. 140-142'C (146-148 "C after recrystallization from benzene).

The Photochemistry of Uracil: A Reinvestigation

“…Both studies were designed to examine questions relevant to understanding the excited state(s) responsible for reaction and to gather kinetic data describing the various excited state processes that Ura undergoes when photolyzed in acetonitrile. The work of Lamola and Mittal (56) in 0.7 mM M solution indicted that two dimers were formed, while the work of Wagner and Bucheck (57) in 0.19 mM M solution suggested that all four isomers might be formed, based on analogy with results from the work of Krauch et al (48) on the photosensitized reaction of Ura in aqueous solution.…”

“…The work of Lamola and Mittal (56) in 0.7 m m solution indicted that two dimers were formed, while the work of Wagner and Bucheck (57) in 0.19 m m solution suggested that all four isomers might be formed, based on analogy with results from the work of Krauch et al. (48) on the photosensitized reaction of Ura in aqueous solution.…”

“…Identification and distribution of the yields of dimers formed when photoreaction of Ura is sensitized by acetone in fluid aqueous solution Krauch et al. (48) and Greenstock and Johns (49) published early indications that all four CBDs of Ura are formed when acetone is used to photosensitize the reaction of the parent compound in aqueous solution. Based on experiments in deoxygenated solution (unspecified concentration of Ura) using radiotracer techniques, Greenstock and Johns found that the various isomers were produced in comparable amounts and provided quantitative measurements of the amount of each dimer formed, while Krauch et al.…”

Characterization C4H6Fe(CO)3.SO2.BF3, the product of an arrested Friedel-Crafts sulfination of butadieneiron tricarbonyl

“…B. Miller, ibid.,90, 1358 (1968). (15) For compound II, (ppm): H" 3.68, Hb 4.25, Hc 4.70, Ha 6.24, He 6.93, Hf 7.23, coupling constants Hz: b ~7, /ab = 1.9, < = 8.2, /of = 4.9, /be = 8.5, /be = 1.4, /ce = 2.0, Jit = 14.5; veo 2120, 2077, 2044 cm-1.Journal of the American Chemical Society / 91:25 j December3, 1969…”

Comparative Study of the Gas-phase Cyclodimer Formations of Uracil and 6-azauracil in Excited State and through Conical Intersections S0/S1

“…[21][22][23][24] All four CDs are formed after irradiation of a fluid solution (water or acetonitrile) and when the aqueous solution is acetone sensitized. [23][24][25][26] The trans-syn cyclodimers of U can be formed also by irradiation of denaturated DNA. 27 The molecular and crystal structure of cis-syn photodimer of U has been proposed by Adman.…”