2-Methylbenzenesulfonic acid → 4-(Thiophen-2-yl)butan-1-ol

A solution of 7.8 g of 4-thien-2-ylbutanol in methylene chloride was prepared and a catalytic amount of toluenesulfonic acid added, followed by dropwise addition of 4.8 ml of dihydropyran. When thin layer chromatography indicated a completed reaction (20 minutes), the reaction mixture was extracted with aqueous sodium carbonate. The organic layer was separated, dried over sodium sulfate and concentrated under vacuum to give 10.1 g of oil residue. This oil was dissolved in 50 ml of ether and placed in a flask under an atmosphere of nitrogen. The solution was cooled to 0° C. and 28 ml of 1.6N butyl lithium in hexane was added dropwise. The cold bath was removed and the reaction mixture stirred at room temperature for 45 minutes. The reaction mixture was cooled to -60° C. and 1.36 g of sulfur added. After 30 minutes of stirring at -60° C. the reaction mixture was allowed to warm to room temperature, the ether was decanted from a gummy solid which had formed and dimethylformamide was added as a replacement solvent. Bromomethanesulfonamide (7.3 g) was added and the reaction mixture was heated to 80° C. After one hour at 80° C. the reaction mixture was allowed to cool to room temperature. The reaction mixture was concentrated under vacuum to give a thick oil residue. The residue was treated with 1N aqueous sodium hydroxide to remove any sulfonamides present. The hydroxide solution was washed with ether several times until the ether wash was colorless. The hydroxide solution was cooled to 10° C. and 6N hydrochloric acid added in order to bring the pH to 8.5. A gummy solid was extracted using ethyl acetate and the ethyl acetate was filtered through a small amount of silica gel, washing the silica gel with ethyl acetate. The ethyl acetate was concentrated under vacuum to give 5.7 g of oil residue. This oil was dissolved in methanol and an aqueous solution of 19.2 g of OxoneR added. After heating at 40° C. for 3 hours the mixture was brought to a boil then allowed to cool. The methanol was removed under vacuum and the aqueous residue was extracted with ethyl acetate. The ethyl acetate was dried over sodium sulfate then concentrated under vacuum to give 5.1 g of oil residue. This oil was chromatographed using 230-400 mesh silica gel and eluting with 45% hexane:45% ethyl acetate:10% methanol. When product fractions were combined and concentrated under high vacuum 2.8 g of liquid product was obtained which was still impure. This oil was dissolved in hot dichloroethane, treated with charcoal and filtered. The filtrate was concentrated somewhat then cooled to -10° C. A solid was obtained upon scratching. Since the solid still gave a poor HPLC analysis it was rechromatographed, this time eluting with 5% methanol in chloroform. When product fractions were combined and concentrated under high vacuum a waxy solid was obtained. m.p. 79°-80° C. N.M.R. (CDCl3, 300 MHz) δ 1.62 (m, 2H), 1.80 (m, 2H), 2.92 (m, 3H), 3.62 (t, 2H), 4.86 (s, 2H), 6.68 (br s, 2H), 6.90 (d, 1H), 7.70 (d, 1H). (Found: C, 34.86; H, 4.92; N, 3.94%. C9H15NO5S3 requires C, 34.49; H, 4.82; N, 4.47%).

1. customa completed reaction (20 minutes)
2. extractionthe reaction mixture was extracted with aqueous sodium carbonate
3. customThe organic layer was separated
4. dry with materialdried over sodium sulfate
5. concentrationconcentrated under vacuum

ORD record

ord-2945b0ed03ab45979b7dcda4ab3c3b0d

Source dataset

uspto-grants-1989_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04812463