29421-92-9

Usage

Chemical Properties

Colorless liquid

InChI:InChI=1/C5H5BrS/c1-4-2-5(6)3-7-4/h2-3H,1H3

Upstream product

• 765-58-2 2-bromo-5-methyl thiophene 
• 18791-75-8 4-Bromothiophen-2-aldehyde 
• 98-03-3 thiophene-2-carbaldehyde 
• 554-14-3 2-Methylthiophene 

Downstream Products

• 86525-71-5 1-(5-methyl-3-thienyloxy)-2,3-O-isopropylidene propane 
• 638-00-6 2,4-dimethylthiophene 
• 149064-43-7 Methyl-tris-(5-methyl-thiophen-3-yl)-silane 
• 30537-01-0 Tris-(5-methyl-3-thienyl)-phosphin 
• 89556-08-1 3-bromo-2-iodo-5-methylthiophene 
• 135967-57-6 4-bromo-2-methylthiophene 1,1-dioxide 
• 82834-44-4 3-bromo-5-methyl-2-nitrothiophene 
• 132564-47-7 3-Bromo-2,4-bis-chloromethyl-5-methyl-thiophene 
• 135423-89-1 Tris(5-methyl-3-thienyl)methanol 
• 30319-03-0 2,3-dibromo-5-methylthiophene 
• 709042-95-5 4-azido-2-methythiophene 
• 16939-14-3 2-methyl-4-phenylthiophene 
• 475288-27-8 6-tert-butyl-2-methyl-8H-indeno[2,1-b]thiopen-8-one 
• 86525-73-7 1-(5-methyl-3-thienyloxy)-2,3-epoxypropane 

Relevant academic research and scientific papers

Synthesis of Trisubstituted Thiophenes via a Halogen Dance Reaction at 2-Bromo-5-methylthiophene

A new example of a selective halogen dance reaction was observed upon lithiation of 2-bromo-5-methylthiophene with LDA under appropriate reaction conditions. A series of 2-substituted 3-bromo-5-methylthiophenes was prepared by reacting the thus selectively generated intermediate 3-bromo-2-lithio-5-methylthiophene with various electrophiles to study scope and limitations of the reaction.

Stepwise mechanism for the bromination of arenes by a hypervalent iodine reagent

A mild, metal-free bromination method of arenes has been developed using the combination of bis(trifluoroacetoxy)iodobencene and trimethylsilyl bromide. In situ-formed dibromo(phenyl)-λ3-iodane (PhIBr2) is proposed as the reactive intermediate. This methodology using PIFA/TMSBr has been applied with success to a great number of substrates (25 examples). The treatment of mono-substituted activated arenes led to para-brominated products (2u-z) in excellent 83-96% yields. Density functional theory calculations indicate a stepwise mechanism involving a double bromine addition followed by a type II dyotropic reaction with concomitant re-aromatization of the six-membered ring.

The catalytic behavior of heterocenes activated by TIBA and MMAO under a low Al/Zr ratios in 1-octene polymerization

A series of SiMe2-bridged ansa-zirconocenes LZrCl2 derived from heterocyclic ligands such as cyclopenta[1,2-b:4,3-b’]dithiophene, 5,6-dihydroindeno[2,1-b]indole and 5,10-dihydroindeno[1,2-b]indole, called “heterocenes” were synthesized and characterized by NMR spectroscopy and by X-ray diffraction analysis. These complexes were activated by triisobutylaluminium (TIBA) at AlTIBA/Zr ratio ～75 and then by MMАO-12 at AlMAO/Zr ratio ～10, and were studied in the polymerization of 1-octene in the absence or presence of molecular hydrogen. In the absence of molecular hydrogen, derivatives of cyclopenta[1,2-b:4,3-b’]dithiophene and dihydroindeno[2,1-b]indole demonstrated high catalytic activity, while dihydroindeno[1,2-b]indole complexes catalyzed slow polymerization with the formation of ultrahigh molecular weight poly(1-octene)s. In the presence of molecular hydrogen, derivatives of dihydroindeno[1,2-b]indole showed an order of magnitude increase in the catalytic activity. β-Hydride elimination, β-hexyl elimination and Zr-Al transfer were detected as the main chain release mechanisms depending on the nature of the ligand used. A novel chain termination with selective formation of –C(Me)=CHCH2– unsaturations was detected. It was found that heterocenes maintained a high catalytic activity up to 120 °C. Due to their high thermal stability and good hydrogen response, heterocenes are promising catalysts for the oligomerization and hydrooligomerization of α-olefins in the production of high-quality motor oil base stocks.

Synthesis of photochromic compounds for aqueous solutions and focusable light

Photochromic compounds with improved performance in pure water have been prepared and characterized. They possess an asymmetrical and extended conjugation system with a 1,2-bis(3-thienyl)perfluorocyclopentene core, additional thiophene rings connected with sulfonic acid residues, as well as terminal pyrid-4-yl and 4-alkoxyphenyl groups. A multistep synthetic route to a key compound with an amino group required for further derivatization has been developed. The complete photocyclization reaction of the initial "open ring" compound (with absorption maximum at 340 nm in MeOH or water) can be performed with a diode laser in pure water or aqueous buffer solutions (without added or-ganic solvents) under irradiation at 366-375 nm, and the reverse ring-opening reaction of the colored "closed ring" compound (λmax = 628 or 624 nm in MeOH or water) takes place under irradiation with visible green or red light (>500 nm). Building block 57, with a secondary amino group, can further be used in the synthesis of practically important, reversibly switchable, fluorescent compounds in which the fluorescent dye (donor) is attached to a photochromic unit (acceptor), and the resonant energy transfer from a donor to the colored form of an acceptor provides a reversible quenching of the fluorescence signal in aqueous solutions.

SYNTHESIS OF CYCLOPENTADIENEDITHIOPHENE DERIVATIVES

A process for preparing cyclopentadiene derivatives having formula (I) wherein T1 is selected from the group consisting of oxygen (O), or sulphur (S); R1, R2, R3 an d R4, are hydrogen atoms, or hydrocarbon radicals; comprising the following steps: a) reacting a compound of formula (II) with a compound of formula (III) in the presence of a palladium or nickel based catalyst and a base; b) contacting the obtained compound with a carbonylating system; and c) treating the product obtained in step b) with a reducing agent.

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

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

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).

THIENYL COMPOUNDS

Compounds of formula I : and pharmaceutically-acceptable salts thereof, wherein Ar and R are as defined in the specification, compositions containing such compounds and the use of such compounds and compositions for use in therapy.