Condensation of acetone with sym-trinitrobenzene. Structure of the bicyclic product

Anionic sigma complexes

“…The anionic ring protons show only a single resonance because of rapid rotation about the C-l-N bond.61 Both methoxide and hydroxide add to C-3 of N,N-dimethylpicramide to yield the complex 20k (Ri = CH50 or HO, R2 = CH3). [59][60] The pmr spectra of these complexes in DMSO are characterized by two low-field doublets (7 ~2 cps) for the sp2 and sp3 ring protons at r 1.5-1.6 and 3.8-3.9. Since there are no ionizable protons in this aromatic, at higher base concentrations addition of a second molecule of base occurs to give a propenide complex (section II.B.3).…”

The reactions of two σ-anionic compounds (Jackson–Meisenheimer adducts) in liquid ammonia studied by13C nuclear magnetic resonance spectroscopy

“…Over two more days a further set of peaks, present in the When the temperature is raised to 230 K the lines assignable to (9) and (10) are partially replaced by an absorption at 6c 170.9. This is tentatively assigned to one or more imines formed from (9) and (10) via dehydration of the gem-amino-hydroxy group to form (11) and/or (12). This last assignment is Since Foster and his co-workers l 3 reported the first bicyclo structure of the type (13), in which R' = R2 = phenyl, Strauss and his group "*14-' 6 have studied related reactions.…”

Condensation-cyclization reactions of electron-deficient aromatics with organic bases. VIII. Ortho substituent attack vs. meta ring attack in 3,5-dinitrobenzophenone

“…Piers and Cheng have found that (-)-«-santonin can be converted into 1 via an eight-step sequence. 4 Although lengthy, this synthesis represents a significant improvement over the method of Howe and McQuillin, since 1 was obtained in about 20% yield overall. Fringuelli, Taticchi, and Traverso have recently reported an apparently useful synthesis of -cyperone.5 These workers found that the tricyclic enone 3, prepared by annelation of cis-4-caranone with 1-penten-3-one, undergoes preferential cleavage of the 8,11 bond of the cyclopropane ring with hydrogen bromide to form the 2-bromopropane derivative 4a which could be converted into a mixture of a-and d-cyperone on dehydrohalogenation.…”