Unsaturated heterocyclic systems. LXXXV. Benzoannelation effects on azocine reactivity. Chemical and polarographic reduction of several mono-, di-, and tribenzomethoxyazocines

Reactions of glycyrrhetic acid derivatives with trifluoromethyl hypofluorite. Preparation of a new triterpenoid system

“…As such rearrangements in small or medium rings can only be suprafacial, it is obvious that the moving methyl would adopt the 18a configuration. As far as we know, this is the first case of a methyl undergoing a [1,3] sigmatropic shift.…”

“…Some thought should be devoted to the curious migration of the 27 methyl group to C-18. As we cannot explain it by two consecutive [1,2] rearrangements we assume that the whole process is concerted, and [1,3] sigmatropic rearrangement of the methyl group takes place according to the following scheme. As such rearrangements in small or medium rings can only be suprafacial, it is obvious that the moving methyl would adopt the 18a configuration.…”

“…The excess of the fluorinating reagent was removed with argon and the solvent was evaporated. Trituration of the residue with hexane containing a small amount of benzene gave 1.9 g (92%) of 4: mp 205°; [a]25D -37.8°; ir Pmax 1730, 1715, 1625, and 1250 cm-1; NMR 4.52 (d, 1 H, H-12, J = 49 Hz), 4.47 (q-like, 1 H, H-3a), 3.67 (s, 3 H, methyl ester group), 2.03 (s, 3 H, acetyl protons), 1.26, 1.17, 1.14, 1.14, 0.86, 0.86, 0.86 ppm for methyls 26, 27, 25, 29, 24, 23, and 28, respectively; CD (c 0.21, dioxane) 25°#400 0, #355 -1790, #330 +52, #282.5 -3061, #240 -104, #230 ~311, #225 -156, 6217.5 -415. For other spectral data see the discussion.…”

One hundred years of benzotropone chemistry

“…Nevertheless, 2-methyoxyazocine ( 96 ) reduces related aromatic 10π-electron dianion 97 ( Scheme 18 ). Paquette’s group investigated benzo-annelation effects on azocine reactivity and the chemical and polarographic reduction of several methyoxy azocines [ 85 – 86 ]. 4,5-Benzotropone ( 11 ) was used as the logical starting material for the synthesis of benzomethoxyazocine 101 ( Scheme 18 ).…”

Palladium-mediated synthesis of a new eight-membered heterocycle

“…2 6-Methoxytribenzazocine has been prepared by Paquette and coworkers. 3 Palladium involving procedures based on different strategies have been recently reported. 4 As part of our continuing interest in the synthesis of cyclic compounds 5 as well as in the reactivity of arylnorbornylpalladium complexes, 6 we have worked out the preparation of a new benzazocine derivative: 5-acetyl-10b,11,12,13,14,14a-hexahydro-11,14-methanotribenz [b,d,f]azocin-6-one.…”