492-97-7Relevant articles and documents
Solution processable alternating oligothiophene-PEO-block-copolymers: Synthesis and evidence for solvent dependent aggregation
Kilbinger,Feast
, p. 1777 - 1784 (2000)
A new route to oligothiophene-PEO-block-copolymers has been developed, in which well-defined α-oligothiophene blocks (from bithiophene to sexithiophene) alternate with poly(ethylene oxide) blocks. These materials show high solubility in common organic solvents. UV/visible and fluorescence studies in solution indicate that the oligothiophene segments are molecularly dissolved in good solvents like chloroform. Aggregation of the oligothiophenes occurs in dioxane-water mixtures, which is manifest by shifts of the UV/ visible absorption maxima towards the blue and quenching of the fluorescence. An oligothiophene length of three thiophenes (terthiophene) is necessary to observe this aggregation phenomenon.
Receptor- And ligand-based study on novel 2,2′-bithienyl derivatives as non-peptidic AANAT inhibitors
Lepailleur, Alban,Lemaitre, Stephane,Feng, Xiao,Santos, Jana Sopkova-De Oliveira,Delagrange, Philippe,Boutin, Jean,Renard, Pierre,Bureau, Ronard,Rault, Sylvain
, p. 446 - 460 (2010)
Arylalkylamine N-acetyl transferase (serotonin N-acetyl transferase, AANAT) is a critical enzyme in the light-mediated regulation of melatonin production and circadian rythm. With the objective of discovering new chemical entities with inhibitory potencies against AANAT, a medium-throughput screening campaign was performed on a chemolibrary. We found a class of molecules based on a 2,2′-bithienyl scaffold, and compound 1 emerged as a first hit. Herein, we describe our progress from hit discovery and to optimization of this new class of compounds. To complete the study, computational approaches were carried out: a docking study which provided insights into the plausible binding modes of these new AANAT inhibitors and a three-dimensional quantitative structure-activity relationship study that applied comparative molecular field analysis (CoMFA) methodology. Several CoMFA models were developed (variable alignments and options), and the best predictive one yields good statistical results (q2 = 0.744, r2 = 0.891, and s = 0.273). The resulting CoMFA contour maps were used to illustrate the pharmacomodulations relevant to the biological activities in this series of analogs and to design new active inhibitors. This novel series of 2,2′-bithienyl derivatives gives new insights into the design of AANAT inhibitors.
Reactions of lithiated aromatic heterocycles with carbon monoxide
Garcia Linares, Guadalupe E.,Nudelman, Norma S.
, p. 569 - 576 (2003)
The reaction of lithium derivatives of aromatic heterocycles with carbon monoxide was studied under several reaction conditions: 2-furyllithium afforded only one product, the tetrahydro-2-furaldehyde (25% yield). On the other hand, 2-thienyllithium and 5-methyl-2-furyllithium gave two and five products, respectively. Although in relatively low yields, formation of highly functionalized compounds takes place in a fast process under mild conditions. For 1,4-dihydroxy-1,4-bis(5-methyl-2-furanyl)butane-2,3-dione, reaction conditions were achieved to obtain this difficult to prepare derivative in 50% yield. To the best of our knowledge, this is the first report on the reaction of lithiated aromatic heterocycles with CO: evidence is given on the involvement of proton transfers in the reactions of 2-furyllithium and 2-thienyllithium, while the reaction of 5-methyl-2-furyllithium seems to proceed through an electron transfer as the first step. Copyright
Laser flash photolysis study on the photoinduccd reactions of 3,3′-bridged bithiophenes
Fujitsuka, Mamoru,Sato, Tadatake,Sezaki, Fumiyasu,Tanaka, Kazuyoshi,Watanabe, Akira,Ito, Osamu
, p. 3331 - 3337 (1998)
Photophysical properties and photoinduced reactions of 3,3′-bridged-2,2′-bithiophenes {dithieno[3,2-b:2′,3′-d]-thiophene, 4H-cyclopenta[2,1-b:3,4-b′]dithiophene, and 4H-dithieno[3,2-b;2′,3′-d]pyrrole (DTP)} and 2,2′-bithiophene (BT) were investigated by observing the transient absorption spectra in the visible and near-IR regions using nanosecond laser flash photolysis. Fluorescence quantum yields for the bridged bithiophenes were low compared with that for BT. An especially low quantum yield for DTP in acetonitrile was attributed to an addition reaction with the solvent. The triplet energy of BT was the lowest amongst the examined bithiophenes, indicating some conformational change in the triplet state. Triplet-energy-transfer reactions at diffusion limited rates were confirmed between bithiophenes and triplet-energy donors or acceptors. Photochemical generation of the radical cations of the bithiophenes was confirmed by the transient absorption spectra, which show good correspondence with those observed in γ-ray radiolysis. It was found that the triplet quenching rates of the electron-transfer reactions were small when the Gibbs energy change for the reaction was ≥ -25 kJ mol-1. The observed tendency agreed with the semi-empirical equation of Rehm-Weller. The generated radical cations decay according to a second-order function, indicating deactivation by a back electron-transfer reaction.
Influence of donor–acceptor conjugation between thiophene-phthalazinone structures containing Sp3 C?N bond on the frontier orbital levels and optic–electronic properties
Han, Jianhua,Cheng, ShengLi,Liu, Cheng,Wang, Jinyan,Jian, Xigao
, p. 3470 - 3483 (2016)
Herein, an electron-deficient phthalazinone unit containing a unique Sp3 hybrid nitrogen atom as an acceptor to cut off the ether bond was presented and three Donor–Acceptor (D–A) conjugated fluoropolymers via Classical Aromatic Nucleophilic Displacement Polymerization (CANDP) method were successfully synthesized. These polymers exhibit excellent thermostability. The 5% weight loss temperature of PDT2TF under nitrogen atmosphere is high, up to 470 °C. This is due to that the D–A conjugation between thiophene-phthalazinone units affects its resonance energy and stabilizes the thiophene-phthalazinone structures. These three fluoropolymers show strong absorptions and fluorescence in visible light region both in solution and thin film states. The band gaps (Eg) of these polymers are narrower than that of their corresponding di-NH capped monomers, owing to the good electronic communication properties of the Sp3 nitrogen atom in the phthalazinone unit. The Eg value of PDT3TF is decreased to 2.03 eV. These results indicate that phthalazinone unit is an efficient acceptor and could exhibit strong D–A effect with thiophene unit. Also, the Sp3 nitrogen atom in the phthalazinone shows good electronic wave function and charge transport properties. This facile CANDP synthetic method combined with Sp3 C?N bond linked electron-deficient phthalazinone unit affords polymers with controllable photoelectric properties.
Preparation and Reactions of Dichlorodithienogermoles
Ohshita, Joji,Nakamura, Masashi,Ooyama, Yousuke
, p. 5609 - 5614 (2015)
The reaction of 3,3′-dilithiobithiophenes with tetrachlorogermane afforded 4,4-dichlorodithienogermoles, which readily underwent substitution on the central germanium atom. Reactions of a dichlorodithienogermole with LiAlH4, MeLi, Me2NC6H4Li, and C6F5MgBr gave the corresponding Ge-substituted products. Dihydrodithienogermole obtained from the reaction with LiAlH4 was further treated with LDA to give a dimer whose structure was verified by a single-crystal X-ray diffraction (XRD) study. Hydrolysis of dichlorodithienogermoles provided cyclotetragermoxanes. Their optical properties were examined with respect to the UV absorption and fluorescence spectra. It was found that one of the cyclotetragermoxanes responded to a nitorobenzene vapor in the solid state, decreasing the PL intensity.
Far- and mid-infrared of crystalline 2,2′-bithiophene: Ab initio analysis and comparison with infrared response
Hermet,Bantignies,Rahmani,Sauvajol,Johnson,Serein
, p. 1684 - 1691 (2005)
Infrared intramolecular vibrations and lattice modes in the crystalline phase of 2,2′-bithiophene (2T) are investigated using the direct method combined with density functional theory (DFT)-based total energy calculations. For the first time, the far- and mid-infrared responses have been calculated from the Γ-point modes and the Born effective charge tensors of the 2T crystalline phase. The relative good agreement between the calculated and experimental infrared spectra allows us to assign the origin of the main features of the experimental spectra, which is of particular interest in the far-infrared domain. These assignments are useful for understanding all the properties of the 2T crystalline phase in which phonon-phonon and electron-phonon interactions play an important role.
A novel approach to a one-pot synthesis of unsubstituted oligo(α-thiophenes)
Buzhansky, Ludmila,Feit, Ben-Ami
, p. 7523 - 7525 (2002)
Oligo(α-thiophenes) α-4T and α-8T were prepared by the following one-pot sequential conversions: thiophene (T) → α-2T → α-4T → α-8T. PdCl2-induced coupling of a mono-α-mercuration derivative of each of the n-mers T, α-2T, and α-4T was applied in these conversions.
Bithienylsilanes: Unexpected structure and reactivity
Lukevics, Edmunds,Ryabova, Victoria,Arsenyan, Pavel,Belyakov, Sergey,Popelis, Juris,Pudova, Olga
, p. 8 - 15 (2000)
5-(2,2′-Bithienyl)hydrosilanes were prepared by reaction of bithienyl lithium with chlorodimethylsilane, dichloromethylsilane and trichlorosilane. It was shown that 5-(2,2′-bithienyl)dimethylsilane possesses higher reactivity in the hydrosilylation reaction of monosubstituted acetylene derivatives compared with (2-thienyl)dimethylsilane. The elongation of the π-conjugated chain leads to increasing selectivity of the hydrosilylation reaction. An unusual structure for bis[5-(2,2′-bithienyl)]methylsilane has been established by X-ray analysis.
Copper(I)-catalysed homocoupling of organosilicon compounds: Synthesis of biaryls, dienes and diynes
Kang, Suk-Ku,Kim, Tae-Hyun,Pyun, Sung-Jae
, p. 797 - 798 (1997)
Copper(I) iodide catalyses the homocoupling of aryl-, alkenyl- and alkynyl-substituted chloro- or fluorodimethylsilanes under mild conditions to afford biaryls, dienes and diynes, respectively.
