アザジテルペノイド (第3報)

9-OximinodehydroabietinsäuremethylesterのBeckmann転位 その2

抄録

The acid, b.p₃ 193-195°, formed by the decomposition of the lactam with conc. hydrochloric acid (cf. Fig 2), separates into two kinds of acids, one (VII) of m.p. 120-122°, [α]_D²⁹: +30.7°, and the other (VIII) of m.p. 111-113°, [α]_D²⁸: +16.7°, by purification of its anilide. (VII) transits to another (VI) of m.p. 189.5-191°, [α]_D²⁸: +71.3°, when treated with potassium hydroxide, and (VI) reverts back to (VII) when heated with dil. hydrochloric acid. The analytical values of (VI), (VII), and (VIII) all correspond to those of C₁₁H₁₆O₄, a monobasic acid and a γ-lactone according to infrared spectral analyses. Reduction of the methyl esters of (VI) and (VII) with lithium aluminum hydride yields the identical triol, m.p. 157-159°, [α]_D¹⁴: +45.5°. The same treatment of the methyl ester of (VIII) affords a triol of m.p. 102-103°, [α]_D¹⁵: -0.6. Both these triols possess two hydroxyls which can be acetylated. Dehydrogenation of (VI) and (VIII) with selenium yields 1, 2, 3-trimethylbenzene. The foregoing experiments suggest that (VI) and (VII) would be represented by one of the A and B formulae shown in Fig. 2 and (VIII) is assumed to be a stereoisomer of (VI) or (VII).