Journal of the Chemical Society. Perkin transactions I p. 427 - 432 (1992)
Update date:2022-08-30
Topics:
Suginome, Hiroshi
Kaji, Makoto
Ohtsuka, Toshiharu
Yamada, Shinji
Ohki, Takashi
et al.
Irradiation of 5α-cholest-1-en-3-one oxime or its 4,4-dimethyl derivative in a protic or aprotic solvent gave 4'α,5'-dihydro-4-nor-5α-cholest-1-eno<2,1-c>isoxazole or the corresponding 3,3-dimethyl-derivative arising from an unprecedented photorearrangement.The molecular structure of the former was established by X-ray crystallographic analysis. 1β-Methoxy-5α-cholestan-3-one oximes or their 4,4-dimethyl derivatives, arising from an unprecedented photoaddition of methanol to the double bond of the enone oximes, were the accompanying products in both of these photoreactions and no lactams were formed.Deuterium-labelling studies on the photoreactions of 5α-cholest-1-en-3-one oxime and its trideuteriated derivative established that a deuteron or a proton is stereospecifically introduced at the 2α-position of the steroidal oxime in this photorearrangement.A pathway which involves an unprecedented stereospecific addition of a proton or a deuteron to the photogenerated, twisted double bond of the oximes from the rear side, followed by fragmentation of the resulting carbocation and an intramolecular 1,3-dipolar addition of the nitrile oxide intermediate, is proposed regarding the formation of the isoxazole from the excited oximes.Deuterium-labelling studies also established that the addition of methanol to the double bond of the oximes is stereospecific too.On the basis of the labelling study it is concluded that the mechanism for the photoaddition of the methanol involves a stereospecific syn addition of the methanol to the photogenerated, twisted, ground-state double bond of the oximes from the rear side.
Taizhou Shengxing Chempharm Co.,Ltd
Contact:+86-576-88516600
Address:Yantou Chemical Zone Jiaojiang Taizhou Zhejiang China
Hangzhou TJM Chemical Trade Co., Ltd
Contact:86-571-88223276 86-13388481653
Address:2221#,Boyuexuan,1860# Binsheng Road,Binjiang District, Hangzhou CityZhejiang Province, 310051, P. R. China
HENAN NEW BLUE CHEMICAL CO.,LTD
website:http://www.newbluechem.com
Contact:86-371-55170693/55170694
Address:Zhengzhou International Trade New Territory,Jinshui District,Zhengzhou ,China
Contact:+(852) 301-98033
Address:Flat C, 23/F, Lucky Plaza, 315-321 Lockhart Road, Wan Chai, Hong Kong
Shanghai birch chemical technology co.,ltd
Contact:+86-21-54096810
Address:No.2588,Jungong Road,Shanghai,China
Doi:10.1111/j.2042-7158.1960.tb12730.x
(1960)Doi:10.1021/ja01288a007
(1937)Doi:10.1021/ja01333a012
(1933)Doi:10.1246/bcsj.57.787
(1984)Doi:10.1016/0040-4039(95)02294-5
(1996)Doi:10.1016/j.dyepig.2014.04.006
(2014)
