Benzoquionones and related compounds. Part 2.¹ Preferred conformations of some acyl-1,4-benzoquinones in solution

Studies based on polarographic reduction potentials, electronic absorption spectra, and ¹H and ¹³C nuclear magnetic relaxation data show that in solution the preferred conformation of formyl-1,4-benzoquinone is that with the formyl and quinonoid groups coplanar, and the formyl carbonyl group anti to the 1-carbonyl, whereas that of acetyl- and pivaloyl-1,4-benzoquinone has the acyl groups approximately perpendicular to the quinonoid ring.