2-Thienyl bromide

Hydroxynicotinic acid Dimethyl sulfate 2-Thienyl bromide Methyl bromide... 

A solution of 18 g of 2-thienyl bromide in 30 ml of tetrahydrofuran Is gradually added to a mixture of 2.6 g of magnesium and 80 ml of tetrahydrofuran under stirring at 50°C. The mixture is stirred for 5 hours at room temperature until the magnesium is entirely dissolved in the solution. 6.2 g of methyl N-methyl-5-methoxy-nipecotinate are added to the mixture. Then, the mixture is refluxed for 4 hours. After the reaction Is completed, tetrahydrofuran is distilled off under reduced pressure. An aqueous ammonium chloride solution is added to the residue, and the solution is extracted with chloroform. The extract is dried and then evaporated to remove chloroform. The viscous oil thus obtained is recrystallired from a mixture of benzene and ether. 7 g of di-(2-thienyl) -(N-methyl-5-methoxy-3-piperidyl)-carbinol are obtained as crystals. Melting point 142°C to 146°C. 

A solution of 18 g of 2-thienyl bromide in 30 ml of tetrahydrofuran is gradually added to a mixture of 2.6 g of magnesium and 80 ml of tetrahydrofuran under stirring at 50°C. The mixture is stirred for 5 hours at room temperature until the magnesium is entirely dissolved in the solution. 

Telluronium Tris-2-thienyl-(Bromide) E12b, 690 (Ar2TeBr2 + Ar —MgBr)... 

A phosphorus substituent has been introduced into the thiophene nucleus by a similar Pd -catalyzed reaction between 2-thienyl bromide and monobutyl alkyl(aryl) phosphonite. 

Also, from 3-thienyl bromide, yields can be increased by modifying the standard conditions (58%). 

Methyl ketones can be prepared by the carbonylation of aryl, benzyl and thienyl bromides and iodides in the presence of tetramethyltin (equation 102). This reaction also requires raised temperature and pressure. [Ni(CO)2(PPh3)2] (101) was used as catalyst.473... 

Barbarella, G. Zambianchi, M. Polyhydroxyl oligofhiophenes. I. Regioselective synthesis of 3,4 - and 3,3 -di(2-hydroxyefhyl)-2,2 -bifhio-phene via Pd catalyzed coupling of fhienyl-stannanes with thienyl bromides. Tetrahedron 1994, 50,11249-11256. 

The solvent-free, microwave-assisted coupling of thienyl boronic acids and esters with thienyl bromides, using aluminum oxide as the solid support, served to rapidly check the reaction trends on changing times, temperature, catalyst, and base and easily optimize the experimental conditions to obtain the desired product in fair amounts. This procedure offers a novel, general, and very rapid route to the preparation of soluble thiophene oligomers. Quaterthiophene 265 was obtained in 6 min by reaction of 2-bromo-2,2 -bithiophene with bis(pinacolato)diborane(4) in 65% yield, whereas dithiophene 266 was obtained with 70% yield. The synthesis of new chiral 2,2 -bithiophenes also was reported. The detailed... 

Transition metal catalyzed processes are useful tools for the synthesis of functionalized thiophenes. Thus for instance, a phosphine-free, palladium catalyzed coupling protocol for the synthesis of 2-arylbenzo[d]thiophenes from various 3-substituted benzo[6]thiophenes and aryl bromides or iodides has been reported <04T3221>. Likewise, 2,2 -bithiophenes have been 5,5 -diarylated directly with aryl bromides in the presence of Pd(OAc)2, bulky phosphine ligands and CS2CO3 <04T6757>. A series of electron-deficient and relatively electron-rich benzo[6]thienyl bromides have been shown to participate in palladium catalyzed amination reactions, as exemplified by the interesting conversion of 63 to the tetracyclic system 64 upon reaction with 2-aminopyridine 65 <04EJO3679>. 

Vinylation or arylation at C(2) in dialkyl (alk-l-enyl)phosphonates may be performed with vinyl bromides or aryl (substituted phenyl, naphthalenyl, thienyl) bromides in systems which contain Pd(OAc)2-(2-MeC6H4)3P-Et3N and, interestingly, the same catalyst system used in conjunction with iodobenzene and dialkylprop-2-enylphosphonates affords products which then isomerize into dialkyl (S-phenylprop-l-enyljphosphonates ". ... 

Koeckelberghs and coworkers subsequently reported the use of an external initiator (o-tolyl)Ni(PPh3)2Br to polymerize 5-bromo-3-alkoxy-2-thienyl magnesium chloride [65]. In this case, the initiator was shown to be incorporated into about 85% of the polymer chains, with the remainder containing Br/Br, H/Br, and H/H. This suggests that the intramolecular transfer of the catalyst does occur, but not exclusively, with some competing intermolecular transfer and chain termination reactions. These side reactions may also be related to the lack of an ortho substituent next to thienyl bromide, which serves to stabihze the resulting Ni(II) complex [46]. 

Even thienyl bromide 33 with the electron-withdrawing and fairly bulky benzothia-zole fragments enters the reaction to form the photochromic product 34 (Scheme 9) [47], As a rule, the yields of the symmetrical photochromes are 30-50 %. 

The usefulness of the Grignard reagent of 3-bromothiophene is somewhat limited as it can only be prepared by the entrainment method. The simultaneous formation of Grignard reagents from 3-bromothiophene and a fivefold molar excess of ethyl bromide gave, however, a 55% yield of 3-thiophenecarboxylic acid upon carbona-tion. With acetaldehyde, a 55% yield of methyl 3-thienyl carbinol... 

The stability of the o-bromothienyllithium reagents at —70°C contrasts sharply with the behavior of o-bromophenyllithium which is very unstable even at — 100°C, readily splitting off lithium bromide to form benzyne (dehydrobenzene).Only by heating bis-(3-iodo-2-thienyl)mercury to 240°C in the presence of tetracyclone could some evidence for the intermediate existence of 2,3-dehydrothiophene be obtained. ... 

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