Reduction of 1,2-benzoquinones to give catechols; 4-methylsulfanyl-1,2-dihydroxybenzene
SyntheticPage 440
DOI:
10.1039/SP440
Submitted Jul 20, 2010, published Jul 20, 2010
Christopher Cooksey (
rsc@chriscooksey.demon.co.uk)
A contribution from
QUINTOX group
Chemicals Used
4-(Methylsulfanyl)-1,2-benzoquinone Page 439
Sodium dithionite (BDH)
Na2HPO4
Procedure
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).
Author's Comments
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-CH
3Se- and 4-Br phenols.
Data
mp 56.8 ºC (lit Winker A, Ger. Offen. 1978, DE 2644591, p. 30, 50-52 ºC)
δH (CDCl3) 6.88d (1H, 1.2), 6.80m (2H), 5.22brs (1H), 5.08brs (1H), 2.44s (3H).
δC (CDCl3) 143.76s, 141.79s, 129.30s, 121.21d, 116.20d, 115.75d, 17.41q.
MS(EI) m/z (%), 156 (100), 141 (64).
Lead Reference
Cooksey CJ, Land EJ, Riley PA, Org. Prep. Proced. Int., 1996, 28(4), 463-467
DOI: 10.1080/00304949609356553
Other References
Winker A, Ger. Offen. 1978, DE 2644591, p. 30.
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Keywords: catechol, quinone, reduction