2,2′,3,3′,4,4′,5,5′,6,6′‐Decafluoro­diphenyl­amine and its 1:1 cocrystal with diphenyl­amine

In the structures of deca­fluoro­diphenyl­amine, C₁₂HF₁₀N, and its 1:1 cocrystal with diphenyl­amine, C₁₂HF₁₀N·C₁₂H₁₁N, the mol­ecules are located on special positions of C₂ symmetry. The NH groups are not involved in hydrogen bonding and the usual face‐to‐face stacking inter­actions between phenyl and penta­fluoro­phenyl rings are not observed in the cocrystal.     

Oxydative Aryl-Aryl-Verknüpfung von 6,6′,7,7′-Tetramethoxy-1,1′,2,2′,3,3′,4,4′-octahydro-1,1′-biisochinolin-Derivaten

Oxidative Aryl-Aryl-Coupling of 6,6′,7,7′-Tetramethoxy-1,1′,2,2′,3,3′,4,4′-octahydro-1,1′-biisoquinoline Derivatives We describe the synthesis of 2 by intramolecular oxidative coupling of 1, 1′-biisoquinoline derivatives 1 (Scheme 1). This heterocyclic system can be considered as a union of two apomorphine molecules and may thus exhibit dopaminergic activity. - The readily available tetrahydrobiisoquinoline 6 was methylated to 11 (Scheme 4) and reduced (with NaBH₃CN) to rac- 7 and (catalytically) to meso- 7 (Scheme 3). Reduction of 11 with NaBH₄ and of the biurethane rac- 9 with LiAlH₄/AlCl₃ afforded meso- and rac- 10 , respectively (Scheme 4). Demethylation of 6 , meso- 10 , meso- and rac- 7 led to 12 , meso- 14 , meso- and rac- 13 , respectively (Scheme 5). The latter two phenols were converted with chloroformic ester to the hexaethoxycarbonyl derivatives meso- and rac- 15 and subsequently saponified to the biurethanes meso- and rac- 16 , respectively (Scheme 5). - In order to assure proximity of the two aromatic rings, the ethano-bridged derivatives meso- and rac- 18 were prepared by condensing meso- and rac- 7 with oxalic ester and reducing the oxalyl derivatives meso- and rac- 17 with LiAlH₄/AlCl₃, respectively (Scheme 6). The ¹H-NMR, spectra at different temperatures showed that rac- 18 populated two conformers but rac- 17 only one, all with C₂-symmetry, and that meso- 17 as well as meso- 18 populated two enantiomeric conformers with C₁-symmetry. Whereas both oxalyl derivatives 17 were fairly rigid due to the two amide groupings, the ethano derivatives 18 exhibited coalescence temperatures of -20 and 30°. - The intramolecular coupling of the two aromatic rings was successful under ‘non-phenolic oxidative’ conditions with the tetramethoxy derivatives 7, 10 and 18 , the rac-isomers leading to the desired dibenzophenanthrolines, the meso-isomers, however, mostly to dienones (Scheme 9): With VOF₃ and FSO₃H in CF₃COOH/CH₂Cl₂ rac- 7 was converted to rac- 19 , rac- 18 to rac- 21 and rac- 10 to a mixture of rac- 20 and the dienone 23b of the morphinane type. Under the same conditions meso- 10 was transformed to the dienone 23a of the morphinane type, whereas meso- 18 yielded the dienone 24 of the neospirine type, both in lower yields. The analysis of the spectral data of the six coupling products offers evidence for their structures. With the demethylation of rac- 20 and rac- 21 to rac- 25 and rac- 26 , respectively, the synthetic goal of the work was reached, but only in the rac-series (Scheme 10). - In the course of this work two cleavages of octahydro-1,1′-biisoquinolines at the C(1), C(1′)-bond were observed: (1) The biurethanes 9 and 16 in both the meso- and rac-series reacted with oxygen in CF₃COOH solution to give the 3,4-dihydroisoquinolinium salts 27 and 28 ; the latter was deprotonated to the quinomethide 30 (Scheme 11). (2) Under the Clarke-Eschweiler reductive-methylation conditions meso- and rac- 7 were cleaved to the tetrahydroisoquinoline derivative 32 .     

On the configuration of 4,4′,6,6′-tetraphenyl-2,2′-dithiopyrylene

The title compound showed in its UV-VIS absorption spectra large red shifts of bands from solution to crystal indicating a pronounced intermolecular interaction between the dithiopyrylene π-electron systems. Dipole moment measurement in benzene solution gave a dipole moment value of 1.90 D which offers a direct evidence for the molecule in cis-configuration.     

Synthesis and structure of (4R,5R)-α,α,α′,α′-2,2-hexaphenyl-4,5-dimethanol-1,3-dioxolane

We report the synthesis of the 1,4-diol (4R,5R)-α,α,α′,α′-2,2-hexaphenyl-4,5-dimethanol-1,3-dioxolane from dimethyl-L-tartrate and benzophenone. The X-ray and the IR structural studies on show that this compound has a preferred conformation with OHPh interactions which are different from related compounds.     

Carbon Magnetic Resonance Spectra of α, β, γ, δ- and α, β, α′, β′- Unsaturated Ketones

Carbon-13 spectra of a series of 26 unsaturated ketones (ortho- and para-cyclo-hexadienones and corresponding open-chain analogues) have been measured by Fourier-transform. Pulse spectroscopy. A complete analysis has been achieved by means of double resonance experiments using noise-modulated and coherent off-resonance proton irradiation and with the aid of non-decoupled spectra. Chemical shifts are interpreted in terms of charge distribution in the dienone system and of methyl substituent effects. Carbon chemical shifts were also obtained for O-protonated ortho- and para-cyclohexadienones. One-bond and long-range carbon-proton and carbon-fluorine spin coupling constants are reported for several compounds.     

Lipophilic Functionalized Cobyrinic-Acid Derivatives. Part 1. Cobester α-monoacids (α,α,α,β,β,β-hexamethyl α-hydrogen Coα, Coβ-dicyanocobyrinates)

The four α,α,α, β,β,β,-hexamethyl α-hydrogen Coα, Coβ-dicyanocobyrinates 2b, d–f , with a free b-, d-, e-, and f-propionic-acid function, respectively, were prepared by partial hydrolysis of heptamethyl Coα, Coβ-dicyanocobyrinate (cobester; 1 ) in aqueous sulfuric acid. The cobester monoacids 2b, d–f were obtained as a ca. 1:1:1:1 mixture which was separated. The monoacids were purified by chromatography and isolated in crystalline form. The position of the free propionic-acid function was determined by an extensive analysis of 2b, d–f using 2D-NMR techniques; an analysis of the C,H-coupling network topology resulted in an alternative assignment strategy for cobyrinic-acid derivatives, based on pattern recognition. Additional information on the structure of the most polar of the four hexamethyl cobyrinates, of the b-isomer 2b , was also obtained in the solid state from a single-crystal X-ray analysis. Earlier structural assignments based on 1D-NMR spectra of the corresponding regioisomeric monoamides 3b, d–f (obtained from crystalline samples of the monoacids 2b, d–f ) were confirmed by the present investigations.     

Form III of 2,2′,4,4′,6,6′‐hexanitro­azobenzene (HNAB‐III)

The crystal structure of form III of the title compound, HNAB [systematic name: bis(2,4,6‐trinitro­phenyl)diazene], C₁₂H₄N₈O₁₂, has finally been solved as a pseudo‐merohedral twin (monoclinic space group P2₁, rather than the ortho­rhombic space group C222₁ suggested by diffraction symmetry) using a dual space recycling method. The significant differences in the room‐temperature densities of the three crystalline forms allow examination of molecular differences due to packing arrangements. An interesting relationship with the stilbene analog, HNS, is discussed. Interatomic separations are compared with other explosives and/or nitro‐containing compounds.