- Hydroquinone-pyrrole dyads with varied linkers
-
A series of pyrroles functionalized in the 3-position with p-dimethoxy benzene via various linkers (CH2, CH2CH2, CH=CH, C=C) has been synthesized. Their electronic properties have been deduced from 1H NMR, 13C NMR, and UV-vis spectra to detect possible interactions between the two aromatic subunits. The extent of conjugation between the subunits is largely controlled by the nature of the linker, with the largest conjugation found with the tmns-ethene linker and the weakest with the aliphatic linkers. DFT calculations revealed substantial changes in the HOMO-LUMO gap that correlated with the extent of conjugation found experimentally. The results of this work are expected to open up for use of the investigated compounds as components of redox-active materials in sustainable, organic electrical energy storage devices.
- Huang, Hao,Karlsson, Christoffer,Stramme, Maria,Sj?din, Martin,Gogoll, Adolf
-
-
Read Online
- Direct Exploitation of the Ethynyl Moiety in Calcium Carbide Through Sealed Ball Milling
-
Ball milling of calcium carbide (CaC2) enables the reaction of its ethynyl moiety with organic electrophiles. This was realized simply by co-milling CaC2 with organic substrates in a sealed jar without the need for an additive or a catalyst. Various ketones including those bearing α-hydrogens were ethynylated in good yields at short reaction times. Aryl halides are also amenable substrates for this protocol as they furnish aryl ethynes through a benzyne intermediate. This method offers a practical and cheap alternative to the established procedures for introducing ethynyl functionalities.
- Hosseini, Abolfazl,Schreiner, Peter R.
-
p. 4339 - 4346
(2020/07/04)
-
- DBU-Mediated Synthesis of Aryl Acetylenes or 1-Bromoethynylarenes from Aldehydes
-
Two well known synthetic organic reactions Ramirez olefination and Corey-fuchs reactions are integrated in one-pot sequential manner for the synthesis of arylacetylenes and 1,3-enynes starting directly from commercially available aldehydes. The bicyclic amidine 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) along with additive NaOH not only exclusively afforded the terminal alkynes directly from the aldehydes, but also enhanced the reaction rate. The dynamic nature of DBU also facilitated the isolation of 1-bromoalkynes intermediate products. Selection of additive from NaOH and H2O served as a switch for the synthesis of terminal alkyne and 1-bromoalkynes, respectively. (Figure presented.).
- Thummala, Yadagiri,Karunakar, Galla V.,Doddi, Venkata Ramana
-
supporting information
p. 611 - 616
(2019/01/04)
-
- A rapid synthesis of lavendustin-mimetic small molecules by click fragment assembly
-
Lavendustin-mimetic small molecules modifying the linker -CH 2-NH- with an 1,2,3-triazole ring have been synthesized via a click chemistry. Two pharmacophoric fragments of lavendustin were varied to investigate chemical space and the auxophoric -CH2-NH- was altered to an 1,2,3-triazole for rapid click conjugation. The small molecules were evaluated against HCT116 colon cancer and CCRF-CEM leukemia cell lines. Among 28 analogues, 3-phenylpropyl ester 26b inhibited CCRF-CEM leukemia cell growth with GI50 value of 0.9 μM.
- Yoon, Jieun,Ryu, Jae-Sang
-
supporting information; experimental part
p. 3930 - 3935
(2010/08/20)
-
- Iodine/Palladium approaches to the synthesis of polyheterocyclic compounds
-
Chemical Equation Represented A simple, straightforward strategy for the synthesis of polyheterocyclic compounds (PHCs) is reported, which involves iterative cycles of palladium-catalyzed Sonogashira coupling, followed by iodocyclization using I2 or ICI. A variety of heterocyclic units, including benzofurans, benzothiophenes, indoles, and isocoumarins, can be efficiently incorporated under mild reaction conditions. In addition, variations of this strategy afford a variety of linked and fused PHCs.
- Mehta, Saurabh,Larock, Richard C.
-
supporting information; experimental part
p. 1652 - 1658
(2010/05/01)
-
- Electrophilic cyclization of 2-chalcogenealkynylanisoles: Versatile access to 2-chalcogen-benzo[b]furans
-
An efficient synthesis of 2-ehalcogen-3-substituted-benzo[b]furan compounds has been accomplished via electrophilic cyclization reaction of 2-chalcogenealkynyl anisoles using I2, ICl, Br2, and PhSeBr as electrophile sources. The product distributions were strongly dependent on the nature of substituents in the aromatic ring of anisole and on the chalcogen atom directly bonded to the triple bond. The 2-chalcogen-3-iodo- benzo[b]furans obtained smoothly underwent conversion to more complex structures of benzo-[b]furan derivatives via palladium- or copper-catalyzed cross-coupling reaction with thiols, diphenyl diselenides, and zincates.
- Manarin, Flavia,Roehrs, Juliano A.,Gay, Rafaela Mozzaquatro,Brandao, Ricardo,Menezes, Paulo H.,Nogueira, Cristina W.,Zeni, Gilson
-
body text
p. 2153 - 2162
(2009/07/01)
-
- Preparation and characterisation of a quinone-functionalised polythiophene film on a modified electrode. Application to the potentiometric determination of glutathione and cysteine concentrations
-
The new compound 3-((2,5-dimethoxyphenyl)ethynyl)thiophene has been synthesised by Sonogashira coupling. A modified electrode coated with a polythiophene film bearing a quinone moiety was obtained by electropolymerisation of the thienyl group followed by anodic oxidation of para-dimethoxyphenyl group. The cyclovoltammetric response resulting from the reaction of glutathione with the benzoquinone moiety was investigated. The responses of the modified electrode as a new potentiometric sensor of reduced thiols are proposed.
- étienne, Stéphanie,Matt, Muriel,Oster, Thierry,Samadi, Mohammad,Beley, Marc
-
p. 9619 - 9624
(2008/12/22)
-
- How the π conjugation length affects the fluorescence emission efficiency
-
How the π conjugation length affects the fluorescence emission efficiency is elucidated by examination of the theoretical and experimental relationship between absolute quantum yield (Φf) and magnitude (Aπ) of the π conjugation lengt
- Yamaguchi, Yoshihiro,Matsubara, Yoshio,Ochi, Takanori,Wakamiya, Tateaki,Yoshida, Zen-Ichi
-
supporting information; experimental part
p. 13867 - 13869
(2009/02/07)
-
- Rigid molecular architectures that comprise a 1,3,5-trisubstituted benzene core and three oligoaryleneethynylene arms: Light-emitting characteristics and π conjugation between the arms
-
In view of increasing interest in light-emitting materials, we have investigated the light-emitting characteristics and occurrence of conjugation between arms of star-shaped rigid molecules that comprise a 1,3,5-triethynylbenzene core and methoxy group-su
- Yamaguchi, Yoshihiro,Ochi, Takanori,Miyamura, Satoshi,Tanaka, Takahiro,Kobayashi, Shigeya,Wakamiya, Tateaki,Matsubara, Yoshio,Yoshida, Zen-Ichi
-
p. 4504 - 4505
(2007/10/03)
-
- Light-emitting efficiency tuning of rod-shaped π conjugated systems by donor and acceptor groups
-
In view of the increasing importance of highly efficient light-emitting materials in chemistry, biological science, and materials science, we investigated the light-emitting efficiency tuning of rod-shaped oligo(p-phenylene ethynylene)s (OPEs, trimeric to pentameric systems) by donor and acceptor groups, so that they emit the very intense fluorescence (Φf ≈ 1.0, log ε ≈ 5) at 460 nm as the desired wavelength region. This goal was achieved by side modification by MeO (donor) groups and end modification by a CN-substituted benzene ring or CF3-substituted pyridine ring (acceptor) of tetrameric p-phenylene ethynylene rod-shaped molecules (Φf = 0.96, λem = 458 nm, log ε = 4.96 for the former and Φf = 0.99, λem = 459 nm, log ε = 4.92 for the latter). The high Φf values for 11 and 12 are interpreted in terms of kr (radiative rate constant) and kd (radiationless rate constant). The linear relationship with a positive slope between Φf and the Hammett σ constant was found for the first time. It is found that kd rather than kr varies with σp-X. The photophysical properties (Φf, λem, λabs, log ε) were not so altered with the solvent polarity, which could be explained by the dipole moments in the excited and ground states. The results would be valuable for the molecular design of highly efficient light-emitting materials. Copyright
- Yamaguchi, Yoshihiro,Tanaka, Takahiro,Kobayashi, Shigeya,Wakamiya, Tateaki,Matsubara, Yoshio,Yoshida, Zen-Ichi
-
p. 9332 - 9333
(2007/10/03)
-
- Banana-shaped oligo(aryleneethynylene)s: Synthesis and light-emitting characteristics
-
(Chemical Equation Presented) Pick of the bunch: Banana-shaped molecules 1 and 2 containing dimethoxybenzene and pyridine units are highly efficient emitters of violet light despite the interruption of the π conjugation because of meta substitution. The c
- Yamaguchi, Yoshihiro,Kobayashi, Shigeya,Wakamiya, Tateaki,Matsubara, Yoshio,Yoshida, Zen-Ichi
-
p. 7040 - 7044
(2007/10/03)
-
- Synthesis of novel (phenylalkyl)amines for the investigation of structure-activity relationships: Part 3. 4-Ethynyl-2,5-dimethoxyphenethylamine (=4-ethynyl-2,5-dimethoxybenzeneethanamine; 2C-YN)
-
An easy and efficient pathway for the preparation of 4-ethynyl-2,5-dimethoxyphenethylamine (=4-ethynyl-2,5-dimethoxybenzeneethanamine; 2C-YN; 1) was developed, an ethynyl analogue of the potent 5-HT2A/C agonists, e.g., 4-iodo-2,5-dimethoxy-amphetamine (DOI; 2b). The ethynyl moiety was introduced by a Pd-catalyzed Sonogashira reaction of (trimethylsilyl)ethyne with N-(trifluoroacetyl)-protected 4-iodo-2,5-dimethoxyphenethylamine (7) in almost quantitative yield within only 1 h. Removal of the Me3Si group was accomplished with Bu4NF. Final N-deprotection by NaOH treatment afforded the novel phenethylamine 1 in an overall yield of 88percent.
- Trachsel, Daniel
-
p. 2754 - 2759
(2007/10/03)
-
- Synthesis, anticancer activity, and inhibition of tubulin polymerization by conformationally restricted analogues of lavendustin A
-
Compounds in the lavendustin A series have been shown to inhibit both protein-tyrosine kinases (PTKs) and tubulin polymerization. Since certain lavendustin A derivatives can exist in conformations that resemble both the trans-stilbene structure of the PTK
- Mu, Fanrong,Hamel, Ernest,Lee, Debbie J.,Pryor, Donald E.,Cushman, Mark
-
p. 1670 - 1682
(2007/10/03)
-
- 2-Amino-4-oxo-6-substituted-pyrrolo[2,3-d]pyrimidines as potential inhibitors of thymidylate synthase [1]
-
Classical, antifolate inhibitors of thymidylate synthase often suffer from a number of potential disadvantages when used as antitumor agents. These include impaired uptake due to an alteration of the active transport system required for cellular uptake, a
- Gangjee, Aleem,Yu, Jianming,Kisliuk, Roy L.
-
p. 833 - 840
(2007/10/03)
-
- A Versatile Two-Stage Synthesis of 2-Substituted Benzofurans from (2-Methoxyphenyl)ethynes
-
(2-Methoxyphenyl)ethynes react with aryl or alkyl halides to give disubstituted alkynes which are converted into the corresponding 2-substituted benzofurans on treatment with lithium iodide in 2,4,6-trimethylpyridine.
- Buckle, Derek, R.,Rockell, Caroline J. M.
-
p. 2443 - 2446
(2007/10/02)
-