Oxidation photooxygenation

From the oxidation of enamines with aromatic nitro compounds a-keto-enamines were obtained in modest yields (70J). Photooxygenation led to cleavage of the enamine double bond (706,707). 

Oxidation of dihydrocoptisine (124), derived from protopine, with m-chloroperbenzoic acid in dichloromethane afforded coptisinephenolbetaine (125) as the hydrochloride in 78% yield (Scheme 26) (82). This oxidation method was applied to dihydroberberine (90) to produce berberinephenolbetaine (121) (53). Additionally, photooxygenation of 90 in methanol containing Rose Bengal gave 121 in 80% yield, further photooxygenation of which led to the epidioxide 122, a 1,3-dipolar cycloaddition product with oxygen (84,85). 

Kondo et al. (182,183) reported a conversion of a fully aromatized phenolbetaine to a phthalide skeleton through photooxygenation. Reduction of norcoralyne (54) with zinc in acetic acid afforded dihydronorcoralyne (374), which was oxidized with m-chloroperbenzoic acid to the fully aromatized phenolbetaine 375 (Scheme 67). Photooxygenation of 375 in the presence of Rose Bengal, followed by reduction with sodium borohydride, gave rise directly to the phthalideisoquinoline 376 in 70% yield. The same phthalide (376) was also obtained from 2 -acetylpapaveraldine (129) (Section III,B,1). 

The keto endoperoxide 90 has been synthesised from 1,4-cyclohexadiene through its photooxygenation, reduction of the resulting diastereoisomeric mixture of endoperoxides 89 and subsequent oxidation (Scheme 60). Some chemistry of 90 is described . 

Fig. 35 Mechanism of formation of hydrogen peroxide in the Wagnerova Type II photooxygenation of alcohols and its in-situ use to epoxidize alkenes and oxidized sulfides.

OXYGEN, OXIDES 0X0 ANIONS PHOTOOXYGENATION SUPEROXIDE DETECTION/MEASUREMENT SUPEROXIDE DISMUTASES SUPERACID... 

The oxaziridine ring system has been formed by the oxidation of C=N double bond . The two-step synthesis of iV-phosphinoyloxaziridines 16 from oximes 15 was described (equation 7) . Irradiation of hydroperoxynitrones 18, prepared by dye-sensitized photooxygenation of 2-methoxyfuran in the presence of oximes 17, led to fraw -oxaziridines 19 in yields up to 89% (equation 8) ". ... 

Different isomers of C qO have been prepared by photooxygenation [48], by MCPBA-oxidation [48], by ozonolysis [49] or they were extracted from fullerene soot [11, 50]. Isolation from fullerene soot and analysis of the product of photooxygenation and thermal ozonolysis yields only [6,6]-closed epoxide structures. As already observed for CgoO, ozonolysis and subsequent photolysis of the ozonide C7QO3 gives different [5,6]-open oxidoannulene structures [49]. 

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