4-(Methylsulfanyl)-1,2-benzoquinone Page 439

Sodium dithionite (BDH)

Na₂HPO₄

A solution of 4-(methylsulfanyl)-1,2-benzoquinone (prepared by nitrosodisulfonate oxidation of 4-(methylmercapto)phenol, 1.0 g, 7.1 mmol) in CHCl₃ (150 cm³) was shaken with a solution of Na₂S₂O₄ (6 g) and Na₂HPO₄ (2.2 g) in water (30 cm³). The red quinone was rapidly decolourised. The CHCl₃ was separated, dried (MgSO₄) and evaporated to give a residue which was flash chromatographed on silica gel 60 (50 g) eluting with ethyl acetate – cyclohexane. Evaporation of the appropriate fractions gave the product as a cream solid (42% based on 4-(methylmercapto)phenol).

Using the same method (no attempt was made to optimise yields), the following 4-substituted catechols were prepared (yield):

CH₃O (34%)

CH₃CH₂CH₂O (72%)

CH₃CH₂CH₂CH₂O (58%)

CH₃CH₂CH₂S (55%)

CH₃CH₂CH₂CH₂S (87%)

HOCH₂CH₂S (47%)

 

The reaction failed (recovered starting material) with 4-CH₃Se-  and 4-Br phenols.

mp 56.8 ºC (lit Winker A, Ger. Offen. 1978, DE 2644591, p. 30, 50-52 ºC)

δ_H (CDCl₃) 6.88d (1H, 1.2), 6.80m (2H), 5.22brs (1H), 5.08brs (1H), 2.44s (3H).

δ_C (CDCl₃) 143.76s, 141.79s, 129.30s, 121.21d, 116.20d, 115.75d, 17.41q.

MS(EI) m/z (%), 156 (100), 141 (64).

Cooksey CJ, Land EJ, Riley PA, Org. Prep. Proced. Int., 1996, 28(4), 463-467

DOI: 10.1080/00304949609356553

Winker A, Ger. Offen. 1978, DE 2644591, p. 30.