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Photochemistry of alpha, beta-Unsaturated Nitro Compounds

A total of twelve α ,β - unsaturated nitro compounds of the form
Ar-C=C-NO2
| |
H R
(where Ar=phenyl, o-methylphenyl, mesityl, α - naphthyl, and β - naphthyl; R=hydrogen, methyl, ethyl, and phenyl) were prepared and irradiated with ultraviolet light. When the corresponding α - oximinoketone was formed, it was recovered and identified. Six of the α , β - unsaturated nitro compounds and one α - oximinoketone had not been previously reported. Yields of irradiation products were determined and a kinetic study performed on these.
The effect of substituents size at the β - position of α , β - unsaturated nitro compounds was investigated. No rearrangement of the α - oximinoketone occurred in β - nitrostyrene where as the oxime was recovered for β - methyl, β - ethyl, and β - phenyl α , β - unsaturated nitro compounds. The rate of rearrangement was not largely affected by the substituent size, although some increase in rate was noted for the β - ethyl compound.
The rearrangement was found to be highly dependent on steric interference by ortho substituents on the aromatic ring. One o-methyl group slowed down the reaction rate and two o-methyl groups completely halted rearrangement to the oxime. Rearrangement of 1-(α - naphthyl) - 2-nitropropylene appeared to be hindered by adjacent hydrogens whereas 1-(α - naphthyl) - 2-nitropropylene rearranged to the oxime at a rate 1.68 times the rate of β-methyl-β-nitrostyrene. An explanation for these observations is proposed in terms of structural considerations.

Identiferoai:union.ndltd.org:WKU/oai:digitalcommons.wku.edu:theses-3309
Date01 May 1977
CreatorsElmore, Charles
PublisherTopSCHOLAR®
Source SetsWestern Kentucky University Theses
Detected LanguageEnglish
Typetext
Formatapplication/pdf
SourceMasters Theses & Specialist Projects

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