Perchloric Acid → 2,3,4,5-Tetrahydro-1-benzothiepine-5-carboxaldehyde

A solution of 20.0 g of methoxymethyltriphenylphosphonium chloride in 60 ml of absolute tetrahydrofuran was treated dropwise at 20° C. under argon with 43 ml of 1.4N n-butyllithium in hexane. The mixture was stirred for 1/4 hour. Thereafter, the mixture was treated with 8.02 g of 3,4-dihydro-1-benzothiepin-5(2H)-one in a small amount of tetrahydrofuran. After 5 minutes, the cooling bath was removed and the reaction mixture was stirred at room temperature for an additional 11/2 hours. Thereafter, the reaction mixture was partitioned between petroleum ether and ethanol/water (8:2). The lighter phase was washed with water, dried over sodium sulfate and evaporated. There were obtained 11.8 g of crude product which were dissolved in 80 ml of tetrahydrofuran and treated under argon with 100 ml of 35% perchloric acid. The reaction mixture was stirred overnight, poured on to ice, extracted with ether, washed with 5% sodium carbonate solution, dried and evaporated. Chromatorgraphy on silica gel (petroleum ether/ethyl acetate 92:8) yielded 5.04 g of 2,3,4,5-tetrahydro-1-benzothiepine-5-carboxaldehyde as a colorless oil.

1. customthe cooling bath was removed
2. stirringthe reaction mixture was stirred at room temperature for an additional 11/2 hours
3. customThereafter, the reaction mixture was partitioned between petroleum ether and ethanol/water (8:2)
4. washThe lighter phase was washed with water
5. dry with materialdried over sodium sulfate
6. customevaporated
7. customThere were obtained 11.8 g of crude product which
8. stirringThe reaction mixture was stirred overnight
9. additionpoured on to ice
10. extractionextracted with ether
11. washwashed with 5% sodium carbonate solution
12. customdried
13. customevaporated

ORD record

ord-90dcdc9e9c9a4ca79c814e9a975248d6

Source dataset

uspto-grants-1992_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05164387