The oxidation of isoeugenol to a variety of canpow& is well docwnented in the literature (l-5).
We have extended this research by examining the effect of dye-sensitized photooxidation on isoeugenol (I), a mananer that has been ifirplicated in the biosynthesis of lignin (6). I Isolation of *llignol-like" dimers from the photanixture gives reason to consider the possibility that photooxidation may contribute to lignin synthesis. In a typical reaction, 1 g (6.18 nrsole) of cis-trans isoeugenol and 25 mg of proflavin _dihydrochloride were dissolved in 100 ml of methanol. The solution, constantly saturated with a stream of oxygen, was photooxidized by two 300-W incandescent lamps for 24 hr. The ether solution of the photomixture, after extraction with water, yielded 1040 mg of crude photoproduct. Blank runs under nitrogen or under oxygen without any dye gave essentially no reaction. Photooxidation of isoeugenol acetate under the same conditions also producec! no products. TLC and colutm chromtography (silica gel, cyclohexane-ether mixtures) showed the presence of, and partially separated, three major photoproducts--A, B, and C. separation of B and C was completed by acctylation of the photomixture before colusm chwmatogranhy. In