Journal of Organic Chemistry p. 88 - 92 (1986)
Update date:2022-08-03
Topics:
Albini, Angelo
Fasani, Elisa
Moroni, Micaela
Pietra, Silvio
The photochemistry of the six azoxybenzene derivatives carrying a methoxy and/or a dimethylamino group in positions 4/4' has been examined in alcogols and in benzene and found to lead to different processes.The photo-Wallach rearrangement takes place for all except the disubstituted derivatives.This process involves an intermediate, which either gives back the starting azoxy or is converted to the final o-hydroxy derivative through acid catalysis as well as by the previously reported basic catalysis or via cleavage to diazonium ions, which can be trapped before recombination.Oxygen shift to yield the isomeric azoxy derivative (only one precedent known) is a general, one-way process, leading in every case to the azoxy benzene with the N->O group far from the ring carrying the stronger electron-donating substituent.Differently from the photo-Wallach rearrangement, this process shows little solvent dependence.The dimethylamino derivatives undergo also or exclusively different fragmentations, such as intramolecular hydrogen abstraction and cleavage of either the N=N or the C-N bond.The solvent and substituent effect upon electronic spectra, reaction quantum yield, and product distribution are discussed.The photochemistry is attributed to a ?,?* state with strong internal charge transfer.
View MoreNanjing distinctions Medical Technology Co., Ltd.
Contact:+86-15996203785 13914714059
Address:nanjing,jiangsu , China
Changzhou Sunsheng Chem Co., Ltd
Contact:+1-(989)-854-0648
Address:No. 28 Yinshan Rd., Xixiashu Industrial Park
website:http://www.sincerityenterp.com
Contact:+86-571-88111846
Address:Binjiang Area, Hangzhou
website:http://www.arromax.com
Contact:+86-0512-62959601 skype:aimmezhang
Address:Suite 401, Bldg A3, 218 Xinghu St.Suzhou Industrial Park 215123, P.R. China
Nanjing Chemlin Chemical Co., Ltd.
website:http://www.echemlin.cn
Contact:+86-25-83697070
Address:Rm.902 Longyin Plaza, No. 217 Zhongshan Rd.(N) Nanjing 210009,China
Doi:10.1016/S0040-4039(00)88709-2
(1982)Doi:10.1007/BF00474473
()Doi:10.1021/jo00872a009
(1976)Doi:10.1016/S0040-4039(00)00115-5
(2000)Doi:10.1248/cpb.23.2669
(1975)Doi:10.1139/v56-119
(1956)