Water → (4-Benzylsulfanyl-5-nitro-thiophen-3-yl)-methanol

Temperature

-50 °C

Diisobutylaluminum hydride (154 mL of a 1.0 M solution in dichloromethane, 154 mmol) was added via cannula over 25 min to a solution of 4-benzylsulfanyl-5-nitro-thiophene-3-carboxylic acid ethyl ester (22.63 g, 70.0 mmol) at −50° C. The reaction mixture was stirred at −50° C. for 2 h, then was warmed to 0° C. and was maintained at that temperature for 35 min. Water (200 mL) was added via addition funnel over 15 min and the resulting suspension was warmed to 25° C. whereupon additional water (200 mL) and D/L-tartaric acid (20 g) were added. After stirring vigorously at 25° C. for 30 min, the reaction mixture was partitioned between 1.0 M aqueous hydrochloric acid solution (300 mL) and dichloromethane (2×400 mL). The combined organic layers were dried over sodium sulfate, filtered and were concentrated in vacuo. Purification of the residue by flash column chromatography (Merck silica gel 60, 40-63 μm; 10-50% ethyl acetate in hexanes) afforded the desired product, (4-benzylsulfanyl-5-nitro-thiophen-3-yl)-methanol (10.52 g, 37.4 mmol, 53%), as a dark brown oil. 1H NMR (400 MHz, CDCl3) δ: 4.21 (2H, s), 4.40 (2H, s), 7.09-7.12 (1H, m), 7.21-7.24 (4H, m), 7.39 (1H, s).

1. temperaturewas warmed to 0° C.
2. temperaturewas maintained at that temperature for 35 min
3. additionwere added
4. stirringAfter stirring vigorously at 25° C. for 30 min
5. customthe reaction mixture was partitioned between 1.0 M aqueous hydrochloric acid solution (300 mL) and dichloromethane (2×400 mL)
6. dry with materialThe combined organic layers were dried over sodium sulfate
7. filtrationfiltered
8. concentrationwere concentrated in vacuo
9. customPurification of the residue by flash column chromatography (Merck silica gel 60, 40-63 μm; 10-50% ethyl acetate in hexanes)

ORD record

ord-d87206f72300401abc79f4e5610fba93

Source dataset

uspto-grants-2012_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08097613B2