Selective and efficient syntheses of phototoxic 2,2′:5′,2″-terthiophene derivatives bearing a functional substituent in the 3′- or the 5-position

Rossi, Renzo; Carpita, Adriano; Ciofalo, Maurizio; Lippolis, Vito

doi:10.1016/s0040-4020(01)96185-x

Cited by 71 publications

(43 citation statements)

References 27 publications

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“…47 All other chemicals were used as received without further purification. The compounds 4-trimethylsilylstyrene, 48 2-trimethylstannylthiophene, 49 and [C6F5Cu]4(toluene)2 35 were prepared according to literature procedures. Reactions and manipulations involving boron species were carried out under an atmosphere of prepurified nitrogen using either Schlenk techniques or an inert-atmosphere glovebox (Innovative Technologies).…”

Section: Methodsmentioning

confidence: 99%

A New Route to Organoboron Polymers via Highly Selective Polymer Modification Reactions

et al. 2004

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We have developed a highly efficient new method for the introduction of Lewis acidic boron centers into the side chains of organic polymers. Our methodology involves three steps: (i) the controlled polymerization of the functional monomer 4-trimethylsilylstyrene (S-Si), (ii) the exchange of the silyl groups in poly(4-trimethylsilylstyrene) (PS-Si) with BBr3 to give the reactive polymer poly(4-dibromoborylstyrene) (PS-BBr), and (iii) the fine-tuning of the Lewis acidity of the individual boron centers through substituent exchange reactions with nucleophiles. Treatment of PS-BBr with ethoxytrimethylsilane and THF respectively yields the moderately Lewis acidic poly(arylboronate)s PS-BOR (R ) Et, 4-bromobutyl). The alkoxy groups in PS-BOR have been exchanged with pinacol to form the air-stable polymer PS-BPin (Pin ) pinacolato). Treatment of PS-BBr with 2-thienyltrimethyltin and pentafluorophenylcopper respectively gives the well-defined highly Lewis acidic triarylborane polymers PS-BTh and PS-BPf (Th ) 2-thienyl, Pf ) 2,3,4,5,6-pentafluorophenyl), which contain triarylborane moieties at every repeat unit along the polymer chain. All polymers have been studied by multinuclear NMR spectroscopy and differential scanning calorimetry. The molecular weights of the arylboronate polymers PS-BOR have been determined by gel permeation chromatography, and the highly selective formation of polymer PS-BPin has been confirmed by static light scattering.

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Section: Methodsmentioning

confidence: 99%

A New Route to Organoboron Polymers via Highly Selective Polymer Modification Reactions

et al. 2004

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“…[13] We used this synthetic approach for compounds 2 and 4. 5-Bromo-2,2¢:5¢,2²-terthiophene was obtained in 45 % yield, following the procedure described by Rossi et al [14] Treatment with CuCN in refluxing DMF affords 4 in 58 % yield (Scheme 2). a,x-Dibromoterthiophene was obtained by bromination of terthiophene with N-bromosuccinimide (NBS) in DMF.…”

Section: Methods B: Rosenmund±von Braun Nitrile Synthesismentioning

confidence: 99%

“…Literature preparations of 5-bromo-2,2¢-bithiophene, 5,5¢-dibromo-2,2¢-bithiophene, 2,2¢:5¢,2²-terthiophene, 5-bromo-2,2¢:5¢,2²-terthiophene, and 5,5¢-dibromo-2,2¢:5¢,2²terthiophene (all in [14,26]), 5-bromo-5¢-cyano-2,2¢-bithiophene and 5-bromo-2-cyanothiophene (both [27]), 5,5¢-distannyl-bithiophene and 2,5-distannyl-thiophene (both [28]), and 2,5-dibromo 3,4-ethylenediethoxythiophene [29] were followed. …”

Section: Methodsmentioning

confidence: 99%

Cyano-Substituted Oligothiophenes: A New Approach to n-Type Organic Semiconductors

Yassar¹,

Demanze

Jaafari³

et al. 2002

Adv. Funct. Mater.

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A series of α,ω‐cyano oligothiophenes with three to six rings, as well as seven β,β′‐substituted cyano terthiophenes have been synthesized using a palladium‐catalyzed coupling reaction via organotin or organozinc intermediates. The structure of an oliothiophene trimer has been determined by X‐ray crystallography; its space group is monoclinic (C2/c) with four molecules per unit cell (Z = 4). The molecules adopt the π–π stacking structure. UV‐vis spectra of these materials as thin films show a bathochromic shift compared to unsubstituted oligothiophenes. These bathochromic shifts are interpreted in the light of charge transfer exciton. Cyano end‐capped sexithiophene (CN‐6T‐CN) sandwiched between various metals (metal/CN‐6T‐CN/metal), to form Schottky diode structures, were fabricated by vapor deposition. The electron injection and rectification ratio strongly depend on the metal contact, namely the work function of the metal is compatible with the electron affinity of the organic material. The current–voltage results are compatible with n‐type conduction in CN‐6T‐CN.

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“…However, the chemical shifts of the methyl group resonating upfield ( δ C 42.2; δ H 3.13) were not explicable if both Z and Y were oxygen 6,7. If the heterocycle was made to be a furan (X = O), the chemical shifts of the β -carbon atoms within the ring were not reasonable.…”

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confidence: 99%

Structure of Pseudocerosine, an Indolic Azafulvene Alkaloid from the Flatworm Pseudoceros indicus

et al. 2009

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The rim of the tunic of the flatworm Pseudoceros indicus is characterized by blue dots on a white background. The isolation and structure elucidation of the blue pigment is reported. It is shown by extensive analysis of spectroscopic data to be an indolic azafulvene, which has been named pseudocerosine.Marine biota continue to provide unique structures with compelling biological activity and/or structural interest. As part of our bioprospecting effort aimed at the discovery of new leads for antitumor compounds, we had the opportunity to sample the marine flatworm Pseudocerus indicus, which was collected by snorkeling in mangrove forests of Palau, Chuuk, and Pohnapei (Micronesia). 1 The animal was observed in high abundance in between the mangrove roots, often feeding on the white colonial ascidian Eudistoma toealensis. We previously have described a series of staurosporine-type indolocarbazole alkaloids from the flatworm and its ascidian prey. [2][3][4] In this paper, we describe the structure elucidation of the blue pigment, which forms the characteristic, well-defined blue spots along the body margin of the otherwise offwhite mantle. 5 Compound 1 was isolated as an intensely blue colored microcrystalline solid in 0.025% yield (dry weight). Optical activity could not be established because of the intense color of the compound (λ max (log ε) 218 (4.31), 260 (4.33), 310 (4.36), 405 (3.40), 569 (3.83), 602 (3.86) indicative of a molecular formula of C 22 H 22 N 3 O 4 S (−0.5 mmu error). This putative molecular formula was corroborated by the presence of 22 distinct signals in the 13 C NMR spectrum of 1 between 22.7 and 172.6 ppm (see Table 1). Most signals in both the proton and the 13 C domain displayed doubling, with a ratio of major to minor of approximately 5:2. On the basis of extensive NMR data analysis, the structure shown in Figure 1 was assigned to compound 1, which we named pseudocerosine.Interpretation of gHSQC data suggested that the 22 carbon atoms were present in the form of four methyl, one methylene, six methine, and 11 quaternary carbon atoms, which meant that two exchangeable protons were present. On the basis of gCOSY data recorded in MeOH-d 4 and MeOH-d 3 , respectively, three spin systems were readily assembled as shown in Figure 2. For fragment a, the coupling pattern of H-5, H-7 and H-8 suggested that they were located in a 1,2,4-trisubstituted aromatic ring.Furthermore, the deshielding evident in the chemical shifts of H-5/H-7 and of H-8 in conjunction with the 13 C chemical shifts of the attached carbon atoms (109.9, 127.6, 118.5 ppm) was suggestive of an indole system.Another two-proton spin system consisted of a vinyl group resonating at 8.22 ppm and 7.32 ppm, respectively, and the J-coupling suggested that these two protons were located ortho to each other (fragment b Figure 2). A third spin system revealed by the gCOSY spectrum consisted of three signals in the form of an ABX system (fragment c Figure 2), which showed an additional coupling to the X-spin when the spectrum wa...

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Selective and efficient syntheses of phototoxic 2,2′:5′,2″-terthiophene derivatives bearing a functional substituent in the 3′- or the 5-position

Cited by 71 publications

References 27 publications

A New Route to Organoboron Polymers via Highly Selective Polymer Modification Reactions

A New Route to Organoboron Polymers via Highly Selective Polymer Modification Reactions

Cyano-Substituted Oligothiophenes: A New Approach to n-Type Organic Semiconductors

Structure of Pseudocerosine, an Indolic Azafulvene Alkaloid from the Flatworm Pseudoceros indicus

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