Bishomochinon

Abstract

22. 11. 7 2 ) Summary. Two isotneric 2,4,6,8-tetrabrorno-cycIooctanc-lI 5-diones (8a and 8b) arc formed in the tetrabromination of cyclooctane-l,5-dione (7). Treatment of a mixture of 8a and 8 b with triethylamine gives rise to anti-1,3-dibromo-bishomoquinone (9), which is reduced with zinc to anti-bishomoquinone (4) in a 65% overall yield. Either 8a or 8b. when heated with copper powder in a high vacuum, affords 1-bromo-(11) and 1,3-dibromo-anti-bishomoquinone (9), anti-bishomoquinone (4) itself as well as its syn-isomer ( 5 ) . T h c anti-configuration was assigned t o 4 on the basis of its reduction t o two dials, one of which showed NMR. cuupling of its two isochronic carbinol protons with one cis-vicinal proton and one trans-vicinal proton. Spectral data of the compounds are discussed. Of particular interest is the inversion of the chemical shifts of exoand endo-mcthylene protons when comparing the XMR.-spectra of untiand s?i7z-bishonioquinone.Einleitung. -Polycyclische Systeme mit gespannten Ringen sind wegen der starren Anordnung ihrer Atome oft besonders geeignet zum Studium der Strukturabhangigkeit von physikalischen Eigenschaften. In der Reihe der Tricyclo[5. 1.0.03,5]octan-2,6-dione (1) -im folgenden ((Bishomochinone)) genanntwaren bisher die Methylderivate 2 und 3 bekannt [Z] [3] [4], welche durch Addition von Diazo-methan und -8than an Durochinon und anschliessende Pyrolyse, Photolyse oder saurekatalysierte Zersetzung der Bis-pyrazoline entstanden waren. In der vorliegenden Arbeit 1 2 3 4 5

The double bamford‐stevens Reaction with Tricyclo [5.1.0.03,5] octane‐2,6‐dione (Bis‐homo‐p‐quinone). Synthesis and Reactions of 4,5‐Dihydro‐4,5‐methano‐1,7‐diaza‐7aH‐indene (4,5‐Homo‐1,7a‐diaza‐indene)

“…spectrum shows the absence of non-aromatic vinyl hydrogens, but a new four-proton signal group has appeared in the 6 = 4.5 to 2.0 ppm range. Two of these signals overlap with the H-C(4) signal to a multiplet at 6 = 2.3-2.0 ppm; since they occur at higher field, they are assigned to the hydrogens at C (6). The other two signals (6 = 4.27 and 3.65 ppm).…”

“…In addition to two cis and one trans coupling, the H-C(5) signal (6 = 1.63 ppm) shows three more splittings with J = 3, 3 and 0.5 Hz. The two couplings of 3 Hz must be with the two vicinal hydrogens at C (6) and that of 0.5 Hz with one of the two hydrogens at C(7) (see below), Only the double bond at C(6)-C(7) of 5 was affected by the hydrogenation: The product (12) no longer has the IR. band at 1655 cm-l and the UV.…”

“…A solution of 0.50 g (3.68 mmol) anti-bis-homo-p-quinone (l), m.p. 186-187' [6] and 1.40 g (7.5 mmol) p-toluenesulfonyl-hydrazide in 15 ml ethanol was heated under reflux. A4fter 15 min the product started to fall out of solution and aftcr 60 min the precipitate was collected and washed well with ethanol.…”

“…m.p. 98-100" [6] was reacted with 0.464 g (2.5 mmol) p-toluenesulfonyl-hydrazide to yield 0.504g of the highly insoluble syn-bis-~~omo-p-quinone-bis-p-toluenesulfonyl-hydrazone (4), which showed decomposition on heating similar to the corresponding anti-isomer; yield 87y0. 2)) converted the signal at S = 6.21 (H-C(3)) to s; irradiation at 6 = 6.92 (H-C(7)) converted the signal at 6 = 5.67 (H-C(6)) to d ( J = 5) : irradiation a t 6 = 1.88 (H-C(5)) converted the signal a t 6 = 5.67 (HX(6)) to d ( J = 8); irradiation at 6 = 5.67 (H-C(6)) removed the long rangecoupling ( J = 0.5) a t 6 = 2.46 (H-C (4)).…”

“…1) as follows: The signal with the unusually high &value (0.06 ppm) is the one which shows a gerninal and two trans couplings. It is, therefore, assigned to the single hydrogen on the 'inside' of the cyclopropane ring (endo-H-C(8)), 6.21 ( J = 2)----. , which sits directly above the rest of the molecule.…”