Heterotricyclodecane. VII. 2,7-Dithia-isotwistan und Derivate

The synthesis of 2,7-dithia-isotwistane ( 18 ) and several of its derivatives ( 13 – 17 ) was achieved starting from endo-2-chloro-9-thiabicyclo[3.3.1]non-6-ene ( 3 ) and using the bicyclic mercaptan 7 as a key intermediate. The isotwistane halides 13 and 14 were treated under reaction conditions suitable for molecular rearrangements involving an epi-sulfonium ion ( a ) by neighbouring group participation. However, only isotwistane derivatives were formed ( 13 → 16 , 13 → 17 , 14 → 16 , 14 → 17 ) and no rearranged products with twistane structure could be isolated.     

A facile synthesis of 2,7‐diazapyrene

2,7‐Diazapyrene is synthesized in three high‐yield steps from commercially available 1,4,5,8‐naphthalene tetracarboxylic dianhydride, which first reacts with concentrated ammonium hydroxide solution at room temperature to give 1,4,5,8‐naphthalenetetracarboxylic diimide (96%). The latter compound is subsequently reduced with borane in refluxing tetrahydrofuran to give 1,2,3,6,7,8‐hexahydro‐2,7‐diazapyrene (77%), which in turn is oxidized with manganese dioxide in refluxing benzene giving 2,7‐diazapyrene (71%).     

The synthesis and characterisation of some 2,7-diazaphenanthrene derivatives

2,7-Diazaphenanthrene was synthesised in moderate yield by the modified Pomeranz-Fritsch reaction by condensing diethoxyethanal with 1,4-benzenebismethanamine, followed by ring closure with 20% oleum, and its spectral characteristics recorded. A similar reaction with diethyl 1,4-benzenebis(3-aminopropanoate) gave either 2,7-diaza-1,8-dimethylphenanthrene or 2,7-diaza-1,8-phenanthrenebis(methylsulphonic acid), depending on the conditions of the ring closure reaction. The bis methiodides of these compounds were tested for phospholipase A₂ inhibitory action but were found to be inactive.     

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).     

Syntheses,structures, and properties of four coordination polymers based on 2,7-di(pyridin-4-yl)-9H-fluoren-9-one

Four coordination polymers (CPs), [Cd(2,7-dpfo)₂(NO₃)₂(CH₃OH)]_n (1) , [Zn(2,7-dpfo)(NO₃)(CH₃COO)]_n (2) , [Co(2,7-dpfo)₂(H₂L)]_n (3) , and [Ni(2,7-dpfo)₂(H₂L)]_n (4) (where 2,7-dpfo is 2,7-di(pyridin-4-yl)-9H-fluoren-9-one and H₄L is 1,1′:4′,1′′-terphenyl-4,2′,5′,4′′-tetracarboxylic acid), were synthesized and structurally characterized. Compounds 1 – 4 were determined by elemental analyses, single crystal X-ray diffraction analyses, powder X-ray diffraction, infrared spectroscopy, and thermogravimetric analyses. Compound 1 displays a one-dimensional (1D) zigzag chain structure, while compound 2 possesses a 1D ladder chain structure. Compounds 3 and 4 are isostructural and consist of 1D chains. The solid-state luminescent properties of 1 and 2 and the magnetic properties of 3 and 4 were also investigated.     

Synthesis of 2,7-dihydro-3,4-5,6-dibenzotellurepin—a new heterocyclic compound

The reaction of 2,2-bis(bromomethyl)biphenyl with tellurium powder and sodium iodide gave the orange compound 1,1-diiodo-2,7-dihydro-3,4-5,6-dibenzotellurepin (1), which is easily reduced with hydrazine hydrate to 2,7-dihydro-3,4-5,6-dibenzotellurepin (2). The latter compound readily forms a black-brown 1:1 complex with TCNQ. The former could be converted to its 1,1-bis(diethyldithiocarbamato)-2,7-dihydro-3,4-5,6- dibenzotellurepin (3) and 1-phenyl-2,7-dihydro-3,4-5,6-dibenzotellurepinium tetraphenylborate (4), respectively, by treatment with NaS₂CN(C₂H₅)₂ and NaB(C₆H₅)₄. The UV-vis, IR, ESR and ¹H NMR spectral data for the new compounds are presented and discussed.     

Reaction of acetic anhydride with monoterpene amine oxides possessing the 2,7-dimethyloctane skeleton

Under the conditions of the Polonovsky reaction, N-(2,7-dimethyl-2,7-octadienyl)-N,N-dimethylamine oxide gives 2,7-dimethyl-2,7-octadienal and N-(2,7-dimethyl-2,7-octadienyl)-N-methylacetamide. Under the same conditions, N-(2,7-dimethyl-2,7-octadienyl)-N,N-dietnylamine oxide dihydrate does not undergo the Polonovsky reaction and gives the rearrangement product, O-(1-isopropenyl-5-methyl-5-hexenyl)-N,N-diethylhydroxylamine, and the hydration product, O-[1-(1-hydroxy-1-methyl)ethyi-5-methyl-5-hexenyl]-N,N-diethylhydroxylamine.The work was accomplished under the financial support of the Russian Fund for the Fundamental Research (93-03-4219).Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1588–1590, September, 1993.     

Kinetic versus Thermodynamic Control Over Multiple Conformations of Di-2,7-naphthihexaphyrin(1.1.1.1.1.1)

Di-2,7-naphthihexaphyrin(1.1.1.1.1.1), a non-aromatic carba-analogue of the hexaphyrin(1.1.1.1.1.1), incorporating two built-in 2,7-naphthylene moieties was synthesized as two separate, conformationally locked stereoisomers. Both conformers followed complex protonation pathways involving structurally different species, which can be targeted under kinetic and thermodynamic control. The neutralization of the ultimate dicationic product, accessible from both stereoisomers of the free base, allowed to realize the complex conformational switching cycle involving six structurally different species.     

Preparation of hexafluoro-1,8- and -2,7-naphthyridine

Hexachloro-1,8- and -2,7-naphthyridine have been prepared from 2,7-dichloro-1,8-naphthyridine and 1,3,6,8-tetrachloro-2,7- naphthyridine respectively. From these products and their starting materials a series of partially and totally fluorine substituted compounds have been derived.     

Phase behavior of poly(9,9-di-n-hexyl-2,7-fluorene)

Here we report the phase behavior of poly(9,9-di-n-hexyl-2,7-fluorene) (PFH), which previously received little attention as compared to its homologues poly(9,9-di-n-octyl-2,7-fluorene) (PFO) and poly(9,9-di-(2'-ethylhexyl)-2,7-fluorene) (PFEH). By means of differential scanning calorimetry, X-ray diffraction, and electron microscopy, we show that there exist four different phases in PFH. The as-cast film is mainly composed of a mesomorphic beta phase with layer spacing of ca. 1.4 nm. This beta phase is inherently metastable and, upon heating above 175 degrees C, transforms into a crystalline (alpha) form that melts into a nematic (N) liquid above 250 degrees C. Upon stepwise cooling, the nematic melt crystallizes into the alpha phase first, followed by solid-solid transformation into another crystalline (alpha') form. Unit cell structure of the alpha form is monoclinic whereas that of the alpha' form is triclinic, but departures from strict orthogonality are slight (by ca. 6 degrees). These observations not only support our previous assignment of two crystalline forms (both orthorhombic in structure) in PFO but also provide insights to the crystalline nature of the polyfluorene series.     

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.     

Pd-catalyzed amidation of 2-chloro- and 2,7-dichloro-1,8-naphthyridines

[reactions: see text] The catalytic amidation between 2-chloro- and 2,7-dichloro-1,8-naphthyridines and primary amides bearing functional groups is reported. When Pd(OAc)2, xantphos, and K2CO3 are used, it is possible to obtain symmetric as well as nonsymmetric 2,7-diamido-1,8-naphthyridines in 50-90% yield with good functional-group tolerance. Monoamidation of 2,7-dichloro-1,8-naphthyridine using 0.9 equiv of the amide proceeded with good selectivity compared to the formation of the diamide, but as a result of the difficult isolation of the product, isolated yields were poor to moderate (22-42%).     

Copolymers comprising 2,7-carbazole and bis-benzothiadiazole units for bulk-heterojunction solar cells

On the basis of theoretical considerations of the intramolecular charge transfer (ICT) effect, we have designed a series of donor (D)–acceptor (A) conjugated polymers based on bis‐benzothiadiazole (BBT). A PPP‐type copolymer of electron‐rich 2,7‐carbazole (CZ) and electron‐deficient BBT units poly[N‐(2‐decyltetradecyl)‐2,7‐carbazole‐co‐7,7′‐{4,4′‐bis‐(2,1,3‐benzothiadiazole)}] ( PCZ‐BBT ), a PPV‐type copolymer poly[N‐(2‐decyltetradecyl)‐2,7‐carbazolevinylene‐co‐7,7′‐{4,4′‐bis‐(2,1,3‐benzothiadiazolevinylene)}] ( PCZV‐BBTV ), and a tercopolymer based on carbazole, thiophene, and BBT poly[N‐(2‐decyltetradecyl)‐2,7‐(di‐2‐thienyl)carbazole‐co‐7,7′‐{4,4′‐bis‐(2,1,3‐benzothiadiazole)}] ( PDTCZ‐BBT ) have been synthesized to understand the influence of BBT acceptor structure and linkage on the photovoltaic characteristics of the resulting materials. Both the HOMO and LUMO of the resulting polymers are found to be deeper‐lying than those of benzothiadiazole‐based polymers. The measured electrochemical band gaps (eV) are in the following order: PDTCZ‐BBT (1.65 eV) < PCZV‐BBTV (1.69 eV) < PCZ‐BBT (1.75 eV). All the polymers provide a photovoltaic response when blended with a fullerene derivative as an electron acceptor. The best cell reaches a power conversion efficiency of 2.07 % estimated under standard solar light conditions (AM1.5G, 100 mW cm^?2). We demonstrate for the first time that BBT‐based polymers are promising materials for use in bulk‐heterojunction solar cells.     

Synthesis of epoxy resins derivatives of naphthalene-2,7-diol and their cross-linked products

The aim of this study was the synthesis of three different epoxy compounds based on naphthalene-2,7-diol (2,7-NAF.EP, 2,7-NAF.WEP, 2,7-NAF.P.EP) and then their cross-linking by triethylenetetramine (TETA). All epoxides were prepared by the reaction of naphthalene-2,7-diol with epichlorohydrin but under different conditions and with other catalysts. The structures of the obtained compounds before and after the cross-linking reactions were confirmed by the attenuated total reflectance Fourier transform infrared spectroscopy (ATR/FT-IR). The ATR/FT-IR spectra of cross-linked compounds show disappearance of the C–O–C bands (about 915 cm^?1) derived from the epoxy groups. DSC and TG/DTG measurements indicated that the obtained materials possess good thermal resistance; they are stable up to about 250 °C. The hardness of the cross-linked products was determined using the Shore D method. The highest value of hardness was obtained for the 2,7-NAF.EP-POL. Additionally, the UV–Vis absorption spectra of the obtained polymers were registered and evaluated.

     

Naphthaquinones—II Derivatives of naphthalene-2,7-diol

The oxidation of 1,6-dibromo-2,7-dimethoxynaphthalene has been reinvestigated and the 1-bromodimethoxy-compound has yielded a new bromonaphthaquinone. A transbromination of 1,6-dibromonaphthalene-2,7-diol has been noticed, whilst an azo-dye from this dibromodiol is shown to have a structure different from that expected from the earlier literature.     

Synthesis and Properties of Poly （aryl ether ketone） Copolymers Containing 2,7-Naphthalene Moieties

IntroductionPoly(aryl ether ketone)s are high performance en-gineering plastics with outstanding physical,chemical,thermal and mechanical properties and have been ap-plied to the aerospace industry,the electronic industry,the automobile industry,the petro…     

Oligo(2,7-fluorene ethynylene)s with pyrene moieties: synthesis, characterization, photoluminescence, and electroluminescence

A series of highly fluorescent, pyrene-modified oligo(2,7-fluorene ethynylene)s were synthesized and fully characterized. Different emissions were observed between pyrene-end-capped and pyrene-centered oligo(2,7-fluorene ethynylene)s. Moreover, these oligomers were applied to fabricate organic light-emitting diodes (OLEDs), and bright blue or green electroluminescence (EL) with good device performances was achieved in multilayer OLEDs. These pyrene-modified oligo(2,7-fluorene ethynylene)s could be used as optoelectronics materials or models to investigate fluorescent structure-property relationship of fluorene derivatives.     

Diisophorone and related compounds—III: 2,7-Epoxydiisophoranes: production and reduction

Alkaline hydrogen peroxide oxidises diisophor-2(7)-en-1-ol-3-one and its lower homologue to the corresponding 2,7-epoxides. Reduction with LAH or catalytic hydrogenation converts 2,7-epoxydiisophoran-1-ol-3-one into the 1,3-diol, with preservation of the epoxide ring. Reduction by hydrazine (Wharton reaction) cleaves the epoxide ring and affords diisophor-2-ene-l,7-diol. the formulation of which is in accord with its hydrogenation to diisophor-2(7)-en-1-ol of established structure, either directly, or after dehydration to diisophorane-2,7-dien-1-ol.2,7-Epoxydiisophorones lacking the 3-keto-function are accessible in good yield from 1-hydroxy-, 1-acetoxy- and 1-chlorodiisophor-2(7)-ene by the action of peroxy-acids in dichloromethane. Of these, 2,7-epoxydiisophoran-1-ol is isomerized to diisophor-7-ene-1,2-diol by the combined action of LAH and AlCl₃. In the carbon-skeleton of the 2,7-epoxides described, the oxirane ring is likely to project above the plane of the A-B rings, on the side opposite ring C.     

New heterocyclic systems based on 1-hydrazino-5,6,7,8-tetrahydro[2,7]naphthyridine: 7,8,9,10-tetra-hydro[1,2,4]triazolo[3,4-a]- and 7,8,9,10-tetra-hydro[1,2,4]triazolo[5,1-a][2,7]naphthyridines

Methods have been developed for the synthesis of new substituted 7,8,9,10-tetrahydro[1,2,4]triazolo-[3,4-a][2,7]naphthyridines from 3-chloro-1-hydrazino-7-methyl-5,6,7,8-tetrahydro-[2,7]naphthyridine-4-carbonitrile. It was shown that on heating in an amine (ethanolamine, pyrrolidine, 2-hydroxy-propylamine), they undergo a Dimroth rearrangement at the triazole fragment, being converted into 7,8,9,10-tetrahydro[1,2,4]triazolo[5,1-a][2,7]naphthyridine derivatives.