- Oxidation of N-Acylindoles by Dimethyldioxirane and Singlet Oxygen: Substituent Effects on Thermally Persistent Indole Epoxides and Dioxetanes
-
Photooxygenation of the N-acylindoles 1a-d afforded the labile indole dioxetanes 2 and the relatively stable allylic hydroperoxides 3.The dioxetanes 2a,c,d were sufficiently stable for isolation and spectral characterization.Additionally, they were characterized by chemical transformations, namely reduction to the indole epoxides 5 by dimethyl sulfide, acid-catalyzed rearrangement to allylic hydroperoxides 3c,d, and thermolysis to the cleavage products 4.Oxidation of the N-acylindoles 1 with dimethyldioxirane afforded the epoxides 5, which were characterized on the basis of their spectral data and chemical transformations to the 2-indolinones 6 and 2-methyleneindoline 7.These decomposition products (except 7e) were fully characterized.The stability of the epoxides 5 depended on the substitution type, i.e., the carbazole epoxide 5c decomposed already at temperatures above ca. -50 deg C, whereas the cyclopentindole epoxide 5b was stable at 20 deg C for days.The latter was unequivocally characterized by X-ray analysis.
- Adam, Waldemar,Ahrweiler, Michael,Peters, Karl,Schmiedeskamp, Bernd
-
-
Read Online
- 1,2-Dioxetane Formation in Photooxygenation of N-Acylated Indole Derivatives
-
Eight N-acylated indole derivatives (1a-h) react with singlet oxygen at low temperature (-5 to -78 deg C) in methanol-d4 or methanol-d4 - methylene chloride-d4 to afford 1,2-dioxetanes 2a-h, whose structures are characterized by low-tempearture 13C NMR and 1H NMR spectra and chemical transformations.These strained 1,2-dioxetanes decompose smoothly and exclusively to dicarbonyl cleavage products 3a-h upon warming to room temperature.
- Zhang, Xiaojun,Foote, Christopher S.
-
-
Read Online
- Methylene Blue-Catalyzed Oxidative Cleavage of N-Carbonylated Indoles
-
The development of a visible-light-mediated oxidative cleavage of electron-deficient indoles is reported. Methylene blue serves as an effective catalyst and the transformation shows a broad substrate scope. A variety of functional groups are well accommod
- Wu, Kui,Fang, Cheng,Kaur, Sarbjeet,Liu, Peng,Wang, Ting
-
-
Read Online
- Oxidation of Indoles by Singlet Oxygen and Dimethyldioxirane: Isolation of Indole Dioxetanes and Epoxides by Stabilization through Nitrogen Acylation
-
Stabilization through N-acylation allowed the isolation of the labile indole dioxetanes 2, which were transformed by dimethyl sulfide deoxygenation to the corresponding indole epoxides 5; the latter were also independently prepared by dimethyldioxirane oxidation.Key words: Indoles, carbazoles, dimethyldioxirane, singlet oxygen, dioxetanes, epoxides
- Adam, Waldemar,Ahrweiler, Michael,Sauter, Markus,Schmiedeskamp, Bernd
-
p. 5247 - 5250
(2007/10/02)
-