5-tert-butylbenzo[b]thiophene synthesis

Yield: 6.7 g

Reaction Conditions:

Stage #1:4-t-butylbenzenethiol;Bromoacetaldehyde diethyl acetal with sodium hydride in tetrahydrofuran at 20; for 15 h;
Stage #2: with phosphorus pentoxide at 175; for 0.75 h;

Steps:

5
12125] A mixture of 7.80 g of bromoacetaldehyde diethylacetal and 20 ml oftetrahydrofuran was added to a mixture of 8.00 g of 4-tert-butylbenzenthiol, 2.10 g of sodium hydride, and 70 ml of tetrahydroffiran. The reaction mixture was stirred for 15 hours at room temperature. Twenty (20) ml of an aqueous saturated ammonium chloride solution was added to the reaction mixture, and extraction was performed three times by using tert-butyl methyl ethet The collected organic layer was washed with water and saturated saline, dried over magnesium sulfate, and then concentrated under reduced pressure. The residues were added to a mixture of 10 g of diphosphorus pentoxide which had been stirred for 45 minutes at 175° C. and 20 g of phosphoric acid, and the residue was stirred for 5 minutes. The reaction mixture was poured into ice water, and extraction was performed three times by using tert-butyl methyl ethet The collected organic layer was washed with water and saturated saline, dried over magnesium sulfate, and then concentrated under reduced pressure. The residues were subjected to silica gel colunm chromatography, thereby obtaining 6.7 g of 5-tert-butylbenzo[b] thiophene.

References:

SUMITOMO CHEMICAL COMPANY, LIMITED;Mukumoto, Fujio;Tamaki, Hiroaki;Kusaka, Shintaro;Iwakoshi, Mitsuhiko US2015/282482, 2015, A1 Location in patent:Paragraph 2125