ChemicalBook CAS DataBase List 5-BROMOBENZO[B]THIOPHENE

5-BROMOBENZO[B]THIOPHENE synthesis

12synthesis methods

Product Name:5-BROMOBENZO[B]THIOPHENE
CAS Number:4923-87-9
Molecular formula:C8H5BrS
Molecular Weight:213.09

5-Bromobenzothiophene is a thiophene derivative and can be used as a pharmaceutical intermediate. It can be synthesized by ring-closure reaction of 1-Bromo-4-[(2,2-diethoxyethyl)thio]benzene with PPA in chlorobenzene.

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Yield:4923-87-9 105 g

Reaction Conditions:

with phosphorus pentoxide in toluene at 80 - 125; for 47 h;

Steps:

4.2

_{(2) Add 600ml of toluene and 50g of polyphosphoric acid into a 2L four-necked flask, stir and raise the temperature to 80°C, Add 50g of phosphorus pentoxide, and then increase the temperature to 115-120°C, Start slowly adding step intermediates while controlling the kettle temperature at 120-125°C. It takes 45 hours. After the addition is complete, keep it at the same temperature for 2 hours. The reaction is complete. Cool down to 50°C, add 200g water to the reaction solution, separate into layers, and take the organic layer Under reduced pressure distillation, 105 g of 5-bromobenzothiolane was obtained.}

References:

CN111423409,2020,A Location in patent:Paragraph 0046; 0049