Light-induced and related reactions of quinones. Part X. Further studies with hydroxymethyl-, vinyl-, and (2-ethoxycarbonylethyl)-1,4-benzoquinones

Abstract

Irradiation of hydroxymethyl-1,4-benzoquinone in [²H₆]benzene gave ([²H₅]phenoxymethyl)-1,4-benzoquinone, with no incorporation of deuterium into the quinonoid nucleus. Irradiation of 2-hydroxymethyl-5- and 2-hydroxymethyl-6-methyl-1,4-benzoquinones in benzene gave the corresponding methyl homologues of phenoxymethyl-1,4-benzoquinone, but 3-methyl-2-phenoxymethyl-1,4-benzoquinone was not formed from 2-hydroxymethyl-3-methyl-1,4-benzoquinone.

Irradiation of [3,3,3-²H₃]-2-(1,4-benzoquinonyl)propene in benzene gave 3-[²H₃]methyl-5-hydroxybenzofuran with neither loss nor scrambling of the label. 1-(1,4-Benzoquinonyl)-1-phenylethylene behaved analogously, but vinyl-1,4-benzoquinone afforded only amorphous material.

Diethyl (1,4-benzoquinonylmethyl)malonate gave ethyl 6-hydroxycoumarin-3-carboxylate when irradiated in benzene containing a trace of oxygen.

The mechanistic significance of these results is discussed.