A mixture of hydroquinone (55 g, 0.5 mol), 1-bromopropane (24.6 g, 0.2 mol) was heated under N₂ to reflux. A solution of KOH (11.2 g, 0.2 mol) in ethanol (80 cm³) was added over 20 m and heating continued for 4 h. After neutralisation (acetic acid, 20 cm³), evaporation gave a white solid which was extracted with chloroform (4 x 50 cm³). The chloroform was evaporated to give an oil containing white crystals (hydroquinone) which was dissolved in petroleum ether (60/80), filtering hot. After cooling, filtration gave white plates (9.72 g, 32%), m.p. 48-50 ºC. Ethylene oxide (3 cm³, 0.06 mol) was added to a test-tube equipped with a gas inlet and gas outlet and cooled in ice. A slow stream on N₂ was passed through then into stirred 4-mercaptophenol (6.3 g, 0.05 mol) containing Et₃N (3 drops) heated on a water bath at 45 – 50 ºC. After 1.5 h, all the ethylene oxide had gone but the reaction was incomplete (NMR) and more (2 x 1.5 cm³) was added, raising the temperature to 70 ºC since the product had solidified. The product was recrystallised from water – ethanol (7:1) to give slightly pink crystals (4.0 g, 47%), m.p. 72 – 74 ºC.

δ_H (DMSO-d₆), 7.17d (2H), 6.65d (2H), 5.5brs (2H), 3.49t (2H), 2.80t (2H)

EI MS m/z(%), 170 (97), 140 (22), 139 (100)

mass 170.0410, calc for C₈H₁₂O₂S 170.0402

Dachs NW, Gruber R, US patent, 1972, 3646220

Naish-Byfield S, Cooksey CJ, Latter AM, Johnson CI, Riley PA, Melanoma Res. 1991, 1(4), 273 – 287, PMID: 1823634