638-00-6Relevant academic research and scientific papers
Catalytic Synthesis of Methylthiophenes
Mashkina,Khairulina
, p. 1794 - 1797 (2019/03/26)
The gas-phase reaction of dimethyl disulfide with thiophene over Co/HZSM-5 catalyst in a helium medium under atmospheric pressure at 250–350°C gave a mixture of mono-, di-, tri-, and tetramethylthiophenes with an overall selectivity of 94–96%.
HETEROARYL COMPOUNDS AND METHODS OF USE THEREOF
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Paragraph 00284, (2013/08/28)
Provided herein are thiophene compounds, methods of their synthesis, pharmaceutical compositions comprising the compounds, and methods of their use. The compounds provided herein are useful for the treatment, prevention, and/or management of various neurological disorders, including but not limited to, psychosis and schizophrenia.
Sterically crowding the bridge of dithienylcyclopentenes for enhanced photoswitching performance
Goestl, Robert,Kobin, Bjoern,Grubert, Lutz,Paetzel, Michael,Hecht, Stefan
supporting information, p. 14282 - 14285 (2013/01/15)
Better switching: The introduction of bulky substituents into the bridge moiety of dithienylethenes led to derivatives exhibiting high photocyclization quantum yields. This novel and versatile form of substitution facilitated tuning of the switching performance without compromising on the optical and redox properties of the ring-open and ring-closed forms (see scheme). Copyright
Highly selective 5-substitution of 3-methylthiophene via directed lithiation
Smith, Keith,Barratt, Mark Lewis
, p. 1031 - 1034 (2008/02/04)
(Chemical Equation Presented) Lithiation of 3-methylthiophene with lithium 2,2,6,6-tetramethylpiperidide (LiTMP) is highly selective at the 5-position, and reaction with a range of electrophiles gives high yields of the corresponding 2,4-disubstituted thiophenes, even when unhindered electrophiles are used.
1,3-bicyclo[1.1.1]pentanediyl: The shortest rigid linear connector of phenylated photochromic units and a 1,5-dimethoxy-9,10-di(phenylethynyl) anthracene fluorophore
De Meijere, Armin,Ligang, Zhao,Belov, Vladimir N.,Bossi, Mariano,Noltemeyer, Matthias,Hell, Stefan W.
, p. 2503 - 2516 (2008/04/01)
An excess of bis-1,3-(4-iodophenyl)bicyclo[1.1.1]pentane, prepared in 63% yield by iodination of 1.3-diphenylbicyclo[1.1.1]pentane, was selectively mono-coupled with 9-ethynyl-1,5-dimethoxy-10-phenylethynylanthracene (26), and subsequently with the zinc derivatives of 1-(2-methyl/methoxy-4-methyl-5- phenylthiophen-3-yl)-2-(2-methyl/methoxy-4-methylthiophen-3-yl) perfluorocyclopentenes (38-H-41-H). Regioselective synthesis of the 2-unsubslituted thiophenes 38-H-41-H required intermediate prepara tion of 2-trimethylsilyl-3,5-dimethyl-4-bromothiophene (37) or 2-trimethylsilyl-5- methoxy-3-methyl-4-bromothiophene (40). Protection of the α-position of the thiophene ring with a 2-trimethylsilyl group blocks the rearrangement of the 4-lithio derivatives into the corresponding 2-lithiated thiophenes. With the bicyclo[1.1.1]pentane frag ment linking the photochromic units 1-3 and 1,5-dimethoxy-9,10-di(phenylethynyl)anthracene as a fluorescent part, quantitative resonance energy transfer between the excited state of the fluorophore (donor) and the closed form of the photochromic units 1-3 (acceptors) was observed. The closed forms of the methoxy-substituted photochromic units 2 and 3 are less resistant to UV light (313 nm) than the closed form of 1.
Reversible red fluorescent molecular switches
Bossi, Mariano,Belov, Vladimir,Polyakova, Svetlana,Hell, Stefan W.
, p. 7462 - 7465 (2007/10/03)
I see red, I see red, I see red: Optically switchable compounds were synthesized whose visible fluorescence can be quenched down to 6% with light at 360-400 nm and then restored with red light from a diode laser. The molecular switch offers potential applications in data storage and far-field microscopy with spatial resolution far below the diffraction limit. (Chemical Equation Presented).
Photochromic compound and optical function device using the same
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Page column 21-22, (2010/01/31)
A novel diarylethene photochromic compound is provided. The photochromic compound is capable of forming an amorphous thin film by itself through a coating method and has an excellent thermostability. The amorphous thin film of the photochromic compound can exhibit a large refractive index between the isomers of the photochromic compound. Thus, using such an amorphous thin film provides an optical function device suitable for an optical memory device and an optical switching device.
Synthesis and Conformation of Dithiametacyclothiophenophanes and Metacyclothiophenophanes
Takeshita, Michinori,Tashiro, Masashi
, p. 2837 - 2845 (2007/10/02)
Dithiametacyclo- -(2,3)-, -(2,4)-, -(2,5)-, and -(3,4)thiophenophanes were prepared by dithiol bis-alkylations and were oxidized with m-chloroperbenzoic acid to the corresponding tetraoxides.Pyrolysis of the tetraoxides under a reduced pressure gave the corresponding metacyclothiophenophanes together with many unexpected compounds.The conformations of the obtained products are also discussed.
Gas-phase heteroaromatic substitution. 14. Attack of dimethylfluoronium ion on 2- and 3-methyl-pyrroles, -furans, -and thiophenes
Cecchi, Patrizio,Pizzabiocca, Adriano,Renzi, Gabriele,Sparapani, Cinzia,Speranza, Maurizio
, p. 2094 - 2103 (2007/10/02)
The gas-phase methylation of 2- and 3-methyl-pyrroles (2P and 3P), -furans (2F and 3F), and thiophenes (2T and 3T) by (CH3)2F+ ions, from γ-radiolysis of CH3F, has been investigated at pressures ranging from 50 to 760 Torr, in the presence of a thermal radical scavenger (O2) and variable concentrations of an added base (NMe3: 0-10 Torr).The mechanism of the methylation process is discussed and the intrinsic positional selectivity of the (CH3)2F+ ions evaluated in the framework of the Charge and Frontier Orbital Control concept.Owing to the very large energy gap between the LUMO of (CH3)2F+ and the HOMOs of the selected heteroaromatic substrates, their gas-phase methylation is characterized by a distinct affinity of the ionic electrophile toward those substrates positions with the highest net negative charge, i.e., the C3 in 2P (100percent), the C4 in 3P (100percent), the heteroatom of 2F and 3F (>80percent), the C5 of 2T (32percent), and the C2 of 3T (47percent).Analysis of the methylated product distribution from 2F and 3F as a function of the experimental conditions reveals that the interaction of the (CH3)2F+ with the heteroatom of furans gives rise to the reversible formation of two sets of electrostatic adducts, i.e., a "chelate" adduct (III) and a single proton-bonded adduct (IV), the first rapidly evolving to the α-substituted heteroarenium intermediate by proximity effects and the latter slowly rearranging to the chelate structure III.Formation of these categories of electrostatic adducts from furans, which is much less extensive in the case of thiophenes and absent in pyrroles, accounts for the apparent pronounced affinity of gaseous alkylating electrophiles, irrespective of their LUMO energy, for the α carbons of furans. Key words: gas-phase ion chemistry, electrophilic aromatic substitution, radiolysis, dimethylfluoronium ions, methylated heteroarenes.
STABLE HETEROARENIUM IONS - VIII SOME TRANSFORMATIONS OF ALKYLTHIOPHENIUM IONS AND NEW SYNTHESIS OF 2-t-BUTYLTHIOPHENE
Belen'kii, L. I.,Yakubov, A. P.
, p. 2471 - 2477 (2007/10/02)
The ratio of isomeric ?-complexes formed from thiophene, t-butyl chloride and AlCl3 was found to be changed while keeping at room temperature whitin 1-2 days.This allows to obtain after deprotonation 2-t-butylthiophene containing only 3percent of 3-isomer.Transformations of ?-complexes formed by protonation of individual 2- and 3-t-butylthiophenes in the presence of AlCl3 have been studied and there was found that isomerization and deprotonation took place during their storage resulting in mixtures of 2- and 3-t-butylthiophenes (the ratio 97:3) which contained considerable quantities of 2,4-di-t-butylthiophene.Deprotonation of t-butylthiophenium ions in the presence of acetone leads to the formation of respective t-butylsubstituted dimethyldithienylmethanes.
