Photochemistry of beta-Methyl-beta-Nitrostyrene

• Main Author: Chen, Peggy
• Format: Others
• Published: TopSCHOLAR® 1974
• Subjects: Chemistry; Physical Sciences and Mathematics
• Online Access: https://digitalcommons.wku.edu/theses/2212; https://digitalcommons.wku.edu/cgi/viewcontent.cgi?article=3222&context=theses

It has been postulated that acetone is the best solvent for the photochemical rearrangement of β-methy1-β-nitrostyrene to 1-phenyl-1, 2-propanedione-1-oxime and it has been postulated to be a sensitizer for this rearrangement. It has also been suggested that the methyl group on the beta-carbon is required for the proper orientation of the nitro group for rearrangement. The irradiation of β-methyl-β-nitrostyrene in several solvents has been studied and the yield of oxime has been recorded. It has been found that several solvents gave yields of oxime higher than that recorded for acetone. We do not, therefore, believe acetone to be necessary to sensitize the rearrangement. The fact that essentially quantitative yields of 1-phenyl-1, 2-propanedione-1-oxime were obtained in aqueous acetone, ethanol and methanol (the yield of oxire in diethyl ether was increased from 45% to 85.6% by the addition of 1% of water prior to irradiation) leads us to believe that water plays an important role in the formation of the oxime. The role of the s-methyl group was verified and the effect of oxygen on the rearrangement was investigated. Irradiation of β-methyl-β-nitrcstyrene in aqueous ethanol under an oxygen stream gave benzaldehyde, benzoic acid and 1-phenyl-1, 2-propanedione as the major products. c oxire could be detected in the reaction mixture.