- Catalytic Deprotonative α-Formylation of Heteroarenes by an Amide Base Generated in Situ from Tetramethylammonium Fluoride and Tris(trimethylsilyl)amine
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Heteroarene formylations in DMF solution proceed in the presence of an amide base catalyst generated in situ from tetramethylammonium fluoride (TMAF) and tris(trimethylsilyl)amine (N(TMS)3). The reaction proceeds at room temperature and has an operationally simple procedure. Various heteroarenes, including benzothiophene, thiophene, benzothiazole, oxazole, and indole derivatives, can be formylated with high functional group tolerance.
- Shigeno, Masanori,Fujii, Yuki,Kajima, Akihisa,Nozawa-Kumada, Kanako,Kondo, Yoshinori
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- Aminobenzoannulated hetero- and carbocycles from 2-azahepta-2,4-dien-6- ynyllithium compounds: Scope and limitation of a novel benzoannulation reaction
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Deprotonation of the N-benzylhetarylmethanimines 9, 12, 15, and 18 at -78°C with subsequent warming to room temperature over 16 hours and treatment with electrophiles furnished polysubstituted aminobenzoannulated heterocycles 19-25 in good to excellent yields. In a similar fashion, the deprotonation of the N-allyl-2-(alk-1-ynyl)phenylmethanimines 26 and 27 led to 2-vinylnaphthalen-1-amines 28 and 29, respectively, in moderate yields. The reaction of N-[(trimethylsilyl)methyl]imine 31 afforded naphthalen-1-amine 33, unsubstituted at the ortho position after removal of the trimethylsilyl group. The deprotonation of imine 34, bearing a trimethylsilyl group on the C≡C bond, gave none of expected amines, but the substituted imine 35, whose structure was identified using 2D NMR spectroscopy. Georg Thieme Verlag Stuttgart.
- Lyaskovskyy, Volodymyr,Froehlich, Roland,Wuerthwein, Ernst-Ulrich
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- Sensitive Assays by Nucleophile-Induced Rearrangement of Photoactivated Diarylethenes
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Upon light-induced isomerization, diarylethenes (DAEs) equipped with reactive aldehyde moieties rearrange selectively in the presence of amines, accompanied by decoloration. In a comprehensive study, the probe structure was optimized with regard to its inherent reactivity in the nucleophile-triggered rearrangement reaction. Detailed structure-reactivity relationships could be derived, in particular with regard to the type of integrated (het)aryl moieties as well as the location of the formyl residue, and the probes' intrinsic reactivity with primary and secondary amines was optimized. Utilizing an ancillary base, the initially formed rearrangement product can engage in a subsequent catalytic cycle, leading to an amplified decoloration process. This additional catalytic pathway allows us to enhance the sensitivity of our method and successfully discriminate between amines and thiols. Moreover, probes that exhibit strong analyte-induced fluorescence modulation have been designed to further decrease the detection limit by using a more sensitive read-out. The optimized DAE probes are promising molecular components for future programmable sensing materials and devices.
- Fredrich, Sebastian,Bonasera, Aurelio,Valderrey, Virginia,Hecht, Stefan
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- Naphtho[2,1-b:3,4-b′]bisthieno[3,2-b][1]benzothiophene-based semiconductors for organic field-effect transistors
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A novel series of air-stable and highly extended π-conjugated naphtho[2,1-b:3,4-b′]bisthieno[3,2-b][1]benzothiophene derivatives, NBTBT-n (n = 6, 8, 10, and 12) and NBTBTF-10, was developed. The influence of various alkoxy-side groups including straight chain with different chain lengths and branched chain on the FET device performance was also investigated. There was a progressive enhancement in the NBTBT-based OFET device performance with an increase in the annealing temperature. The OFET devices based on NBTBT-10 fabricated by vacuum deposition exhibited the best performance with a hole mobility of 0.25 cm2 V-1 s-1 and an on/off ratio of 105-106 after annealing at 220 °C. In addition, fluorinated naphtho[2,1-b:3,4-b′]bisthieno[3,2-b][1]benzothiophene, NBTBTF-10, showed good p-type transistor behaviour with a hole mobility of 0.24 cm2 V-1 s-1 and an on/off ratio of 106-107 which was achieved at a lower annealing temperature of 140 °C, suggesting the important contribution of the dipole-dipole interactions induced by the fluorine atoms in the molecular packing. As a result, the naphtho[2,1-b:3,4-b′]bisthieno[3,2-b][1]benzothiophene framework shows promise as a useful building block to construct organic semiconductors for next-generation high performance organic electronics.
- Li, Zhaoguang,Zhang, Ji,Zhang, Kai,Zhang, Weifeng,Guo, Lei,Huang, Jianyao,Yu, Gui,Wong, Man Shing
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supporting information
p. 8024 - 8029
(2015/08/06)
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- ROBUST PHOTOCHROMIC COMPOUNDS WITH SILICON- OR PHOSPHORUS-CONTAINING HETEROCYCLIC RING AND PRODUCTION THEREOF
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In one embodiment, provided are a new class of diarylethene-containing photochromic compounds with the incorporation of silicon-or phosphorus-containing heterocycles into the "ethene" part of the diarylethene backbone that has been shown to be capable of displaying tunable, robust and thermally stable photochromic properties. Also provided are methods for synthesizing these compounds, as well as uses of these compounds as these compounds may be used as the photochromic layer in an optical recording material and other optical functioning devices.
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- Directed metalation and regioselective functionalization of 3-bromofuran and related heterocycles with NaHMDS
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A mild and regioselective functionalization protocol for 3-bromofuran and analogs has been developed. Selective metalation and functionalization of C2 can be achieved as a result of the directing effect of the adjacent electron-withdrawing bromo group. In addition, the C5 position can also be selectively functionalized by blocking the C2 position via silylation or by simply controlling the reaction temperature. These functionalized compounds bearing a C3 bromo substituent may be further elaborated by utilizing a Suzuki-Miyaura cross-coupling procedure.
- Zhao, Hang,Dankwardt, John W.,Koenig, Stefan G.,Singh, Surendra P.
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supporting information; experimental part
p. 166 - 169
(2012/01/30)
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- Palladium-catalyzed coupling reaction of 3-bromo benzo[b]furan, -thiophene and -selenophene 2-carboxaldehyde. Preparation of tetracyclic heteroaromatic derivatives
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3-Oxo-2,3-dihydrobenzo[b]furans, -thiophenes and -selenophenes 1a-c afforded the bromo-aldehydes 2 under Vilsmeier-Haack-Arnold conditions. Palladium-catalysed aryl-aryl coupling of 2 with o-formyl-phenylboronic acid allowed the formation of dialdehydes 3 which underwent McMurry cyclisation or pinacol condensation to yield polycyclic aromatic derivatives 4 or the dihydroxylated compounds 5.
- Kirsch, Gilbert,Deprets, Stéphanie
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p. 427 - 430
(2007/10/03)
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- Synthesis of novel 2-aminoimidazo[4,5-b]pyridines, including the thieno analogue of the cooked-food mutagen IFP
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Eight new compounds, including three new ring systems obtained via the Friedlunder condensation of ortto-aminothiophenecarbaldehydes 11, 21 and 24 with creatinine (8), are reported. The condensation afforded 1, which is the thieno analogue of the cooked-food mutagen IFP (2-amino-1,6-dimethylfuro[2,3-e] imidazo[4,5-b]pyridine), and the benzothieno[2,3-e]- and benzothieno[3,2-e] imidazo[4,5-b]pyridines 2 and 3. Attempts to condense 11 with isocreatinine (12) were unsuccesful. Desulfurization of 3 gave the known cooked-food carcinogen PhIP, The 2-nitro (4) and 2-hydroxy (5) derivatives of 3 are reported. The related 2-amino-1-methyl-imidazo[4,5-b]benzothiophene (25) was synthesized by a different route. Fully assigned 1H and 13C nmr data of all new compounds are reported.
- Bjoerk, Malin,Grivas, Spiros
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p. 101 - 109
(2007/10/03)
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- Synthesis of novel chiral thiophene-, benzothiophene- and benzofuran-oxazoline ligands and their use in the enantioselective Pd-catalyzed allylation
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Novel thiophene, benzothiophene and benzofuran-oxazoline ligands 6-11 containing a diphenylphosphino group at different positions of the heterocyclic skeleton have been prepared and used in the enantioselective allylation. The advantage of these new ligands is their easy accessibility and their high reactivity. The best results were obtained with ligand 9 to give the product 13 in 97.0% ee with 92% yield in 2 hours at 0°C.
- Tietze, Lutz F.,Lohmann, J. Klaas
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p. 2083 - 2085
(2007/10/03)
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