ChemicalBook CAS DataBase List 2-BROMOBENZO[B]THIOPHENE

2-BROMOBENZO[B]THIOPHENE synthesis

5synthesis methods

Product Name:2-BROMOBENZO[B]THIOPHENE
CAS Number:5394-13-8
Molecular formula:C8H5BrS
Molecular Weight:213.1

95-15-8

5394-13-8

To a solution of benzo[b]thiophene (2.0 g, 15 mmol) in tetrahydrofuran (20 mL) was slowly added n-butyllithium (2.5 M hexane solution, 12 mL, 30 mmol) dropwise at -70 °C and under nitrogen protection. The reaction mixture was stirred continuously at this temperature for 30 minutes. Subsequently, N-bromosuccinimide (5.3 g, 30 mmol) was added and the reaction system was slowly warmed from -70 °C to room temperature over 1 hour. Upon completion of the reaction, the reaction was quenched with saturated aqueous ammonium chloride solution (20 mL) followed by extraction with ethyl acetate (3 x 30 mL). The organic phases were combined, concentrated in vacuum, and the residue was purified by silica gel column chromatography [eluent: petroleum ether/ethyl acetate = 100:1] to afford 2-bromobenzothiophene (0.50 g, 16% yield) as a white solid.

95-15-8 Synthesis

95-15-8
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5394-13-8
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Yield:5394-13-8 81%

Reaction Conditions:

Stage #1:Benzo[b]thiophene with sodium 2,2,6,6-tetramethylpiperidide in hexane at 25; for 0.5 h;
Stage #2: with 1,1,2,2-tetrabromoethane in hexane at -78; for 1 h;

Steps:

8.7 Experiment Number 7
General procedure: Benzo[b]thiophene was used as an arene, and 1,1,2,2-tetrabromoethane (Br₂HCCHBr₂) was used as an electrophilic reagent. The arene was reacted with Na-TMP in the same manner as in Experiment Number 2, the electrophilic reagent was added thereto and reacted therewith at -78° C. for 1 hour, the product was then evaluated, and the yield of isolated 2-bromo-benzo[b]thiophene in which a bromo group (-Br) was added at 2-position of benzo[b]thiophene was calculated. The isolated yield was 81%.

References:

KOBELCO ECO-SOLUTIONS CO.,LTD.;MURAKAMI, Yoshiaki;FUKUSHIMA, Miyuki;TAKAI, Kazuhiko;ASAKO, Sobi US2019/359571, 2019, A1 Location in patent:Paragraph 0127; 0130; 0131; 0140; 0141

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