Photochemistry of the phthalimide system: reduction, addition, and cyclization

✍ Scribed by Yuichi Kanaoka; Koichi Koyama

• Publisher: Elsevier Science
• Year: 1972
• Tongue: French
• Weight: 179 KB
• Volume: 13
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(01)94356-4

✦ Synopsis

Although photoreactions of amide groups have been well documented (l), very little is known about imide derivatives with the exception of photochemical additions to some maleimides (1). In N-substituted phthalimides the carbonyl groups as part of a strained five-membered ring system, are activated. The rigid geometrical arrangement of the polar groups allows for effective intramolecular interaction between the carbony and certain side chain groups whereby the symmetrical structure and the presence of two equally reactive carbonyl groups increases the probability of such interaction by a factor of TWO. We wish to report on the general photochemical behavior and pertinent synthetic aspects of N-substituted phthalimides.

N-Alkylphthalimides were irradiated with 1KW high pressure mercury la& for 0.5 -8 hr and the reaction mixtures were purified by preparative tic or column chromatography ( silica gel ). When alcohol was employed as a solvent, dihydro products 1 ( R = CH3,C2H5 )(3) with one imide carbonyl group reduced were isolated in 30 -40% yield (4), accompanied by 2 resulting from the addition of the alcohol ( R'CH20H ) to the imide carbonyl