Synthese von 2,7-Dioxa-isotwistan und 2,7-Dioxatwistan. Vorläufige Mitteilung

The syntheses of 2,7-dioxa-isotwistane ( 14 ), 2,7-dioxa-twistane ( 19 ), and some of their derivatives ( 6 – 13 and 15 – 18 ) are described. The twistane-skeleton was obtained by a molecular rearrangement starting from the iodo-iso-twistane compound 8 .     

[4](2,7)troponophane

The title compound $\text{5}$ and its dehydro analog $\text{6}$ were synthesized from $\text{10}$ and $\text{9,}$ respectively, and their physical properties were examined. Tropone ring in these compounds are deeply bent to tub shapes and conjugation of the carbonyl group is greatly reduced.     

Synthesis of 2,7-disubstituted-4,5,9,10-tetraazapyrenes

2,7-Dimethyl-4,5,9,10-tetraazapyrene (VI) was synthesized by the catalytic hydrogenation of 4,4′-dimethyl-2,2′,6,6′-tetranitrobiphenyl (IIa) with W-2 Raney nickel in the presence of alkali. 4,4′-Dicarbomethoxy-2,2′,6,6′-tetranitrobiphenyl (IIc) under similar conditions in neutral medium gave 4,4′-dicarbomethoxy-2,2′,6,6′-tetraaminobiphenyl (IV) which on oxidation gave 2,7-dicarbomethoxy-4,5,9,10-tetraazapyrene (V). 2,7-Dimethyl-, 2,7-dimethoxy-, and 2,7-diacetamido-4,5,9,10-tetraazapyrene di-N-oxides (III a,b,c) were obtained by catalytic reduction of the corresponding 4,4′-disubstituted-2,2′,6,6′-tetranitrobiphenyls with W-7 Raney nickel in the presence of alkali. Compound VI on oxidation with hydrogen peroxide gave the di-N-oxide (IIIa).     

Photodimerization of 1H-azepine-2,7-dione

1H-Azepine-2,7-dione 2 afforded photodimer 8 by irradiation using a high or low pressure mercury lamp. Photodimer 8 had a unique structure which must have formed with the prototropy in one of the two molecules of compound 2 . Measurement of the fluorescence spectra of 2 indicated a spectrum of the excimer during the dimerization of 2 . Irradiation of the dimer of 2 at its wave-length of maximal absorption failed to cause it to change into a monomer of 2 .     

2,7-二甲氧基-3,6-二苯氧基萘的合成

以3,6-二溴-2,7-二羟基萘为起始原料,与硫酸二甲酯经甲醚化反应得3,6-二溴-2,7-二甲氧基萘(2);2与苯酚在碘化亚铜催化下经取代反应合成了新化合物——2,7-二甲氧基-3,6-二苯氧基萘,总收率82.5%,其结构经1H NMR,13C NMR,ESI-MS和元素分析表征。     

2.2](2,7)-Fluorenophanediene, [2.2.2](2,7)-fluorenophanetriene, and their fluorenide ions

The McMurry coupling of 2,7-diformylfluorene affords a dimer, anti-[2.2](2,7)-fluorenophanediene, and a trimer, [2.2.2](2,7)-fluorenophanetriene, as cyclic oligomers. X-Ray crystallography of the dimer establishes its strained, layered structure with anti-conformation. While the fluorenyl groups of the dimer do not show any sign of rotation in the variable temperature 1H NMR spectra up to 120 degrees C, those of the trimer are fast rotating even at -50 degrees C. Treatment of the dimer and trimer with KH in DMSO furnished the respective dianion and trianion that are stable at room temperature in the solutions. While the trianion shows substantial conjugation through the etheno bridges, the dianion shows little conjugation through the etheno bridges and almost no proton-deuterium exchange of the fluorenyl C9-H with the solvent DMSO-d6 probably due to stereospecific protonation-deprotonation associated with the tightly layered structure.     

Macrocyclic 2,7‐Anthrylene Oligomers

A macrocyclic compound consisting of six 2,7‐anthrylene units was successfully synthesized by Ni‐mediated coupling of the corresponding dibromo precursor as a novel π‐conjugated compound. This compound was sufficiently stable and soluble in organic solvents due to the presence of mesityl groups. X‐ray analysis showed that the molecule had a nonplanar and hexagonal wheel‐shaped framework of approximately S₆ symmetry. The dynamic process between two S₆ structures was observed by using the dynamic NMR technique, the barrier being 58 kJ mol^?1. The spectroscopic properties of the hexamer were compared with those of analogous linear oligomers.     

Electron transfer within 2,7-dinitronaphthalene radical anion

The optical spectrum of 2,7-dinitronaphthalene radical anion generated by Na(Hg) reduction in acetonitrile containing a large excess of cryptand[2.2.2] exhibits a Hush-type intervalence charge-transfer band at 1070 nm, estimated to correspond to an off-diagonal matrix coupling element of 310 cm(-)(1). The interpolated rate constant for intramolecular electron transfer at 293 K measured by ESR between 225 and 320 K for this solution is 3.1(+/-0.2) x 10(9) s(-)(1). Rate constants estimated in two ways from the optical parameters using the Marcus-Hush assumption that the diabatic surfaces should be parabolae are 1.0 and 0.11 x 10(9) s(-1), and those using diabatic surfaces that fit the observed charge-transfer band are 9.6 and 3.4 x 10(9) s(-)(1), when used with an electron-transfer distance on the adiabatic surfaces of 6.42 A. Similar measurements and comparisons were also carried out using dimethylformamide and butyronitrile as solvents. The success of simple, classical two-state Marcus-Hush theory precludes an electron-hopping mechanism. UHF calculations predict a planar unsymmetrical gas-phase structure for 1,3-dinitrobenzene radical anion but give serious spin contamination. Semiempirical AM1 calculations using singles excitation configuration interaction with an active space of 70 orbitals and the COSMO solvent model also give a planar unsymmetrical structure. These calculations make the internal vibrational component of the reorganization energy nearly constant, and much smaller than the solvent reorganizational component, and predict the transition energy to lie between that observed in acetonitrile (9360 cm(-1)) and those observed in dimethylformamide (8100 cm(-1)) and butyronitrile (8040 cm(-1)).     

Phosphorylation of aminomethylated derivatives of 2,7-dihydroxynaphthalenes

Phosphorylation of 2,7-dihydroxynaphthalene derivatives, containing different amine components was performed by full amides of phosphorous acid. A substantial effect of the intramolecular hydrogen bond on the process of phosphorylation was shown. Cyclophosphorylation was performed and principal possibility of the synthesis of naphthophosphacrownaphanes having aminomethyl linkers was shown. Mannich aminomethylation of naphthophosphacyclophanes was found to be impossible.     

2,7-functionalized indoles as receptors for anions

A series of 2,7-functionalized indoles have been synthesized with appended amide and/or urea or thiourea groups. Anion complexation studies show a marked difference in the mode of interaction of carboxylates with indole-ureas vs indole-amides.