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 Morewebsite:http://www.herbpurify.com
Contact:0086-028-85249238
Address:Room709-C1,Incubator Building, Tianfu Life Science Park No.88,Keyuan Road,Gaoxin district,Chengdu City,Sichuan Prov,China
Lanling Hongchuang Flame Retardant Co., Ltd.
Contact:+86-531-68858132
Address:East Huafeichang Road, Cangshan County, Linyi, Shandong, China (Mainland)
Melone Pharmaceutical Co., ltd
Contact:+86-411 82593920, 82593631
Address:No 232, JInma Roda, Development Zone, Dalian, China
Suzhou Chiral Pharmaceuticals Co., Ltd.
Contact:86-0512-63197058
Address:Building A, No. 2358, Chang'an Road, Wujiang Science Park
Contact:13120882795;+86-21-34621078;+86-021-31122318
Address:Suite 2,No.2715 Longwu Road
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)