2-Methoxybenzene-1,4-diol → 2-Methoxy-1,4-benzoquinone

To a vigorously stirred solution of NaIO4 (33.5 g, 157 mmol, Baker) in H2O (1500 mL), there was added solid 2-methoxyhydroquinone (11.00 g, 50.0 mmol) in portions. The reaction immediately became dark orange. The reaction was allowed to stir for 1 h at rt and was extracted with CH2Cl2 (3×150 mL). The extract was washed with half saturated brine (1×150 mL), filtered through cotton and the solvent removed in vacuo to yield 2-methoxybenzoquinone as an orange solid (10.5 g) which was of sufficient purity (TLC analysis, 10% EtOAc/90% CHCl3) for further reaction. The crude quinone was combined with toluene (150 mL) and hydroquinone (1.0 g, Mallinkrodt). Neat 2,3-dimethyl-1,3-butadiene (8.3 g, 101 mmol, Aldrich) was added. The reaction was allowed to stir overnight at 65° C. under N2. TLC (10% EtOAc/90% CHCl3) indicated total consumption of the dienophile. The solvent was removed in vacuo to yield a dark solid. This was triturated with MeOH (100 mL) at rt to give a beige solid. Crystallization from MeOH (dissolved in 140 mL, allowed to cool to rt) yielded a fluffy colorless solid (10.2 g, 64%, >95% pure by 1H NMR analysis); mp 133°-134° C. (MeOH); 1H NMR (CDCl3) δ1.62 (s, 6H), 2.12 (m, 2H), 2.42 (m, 2H), 3.09 (m, 1H), 3.20 (m, 1H), 3.78 (s, 3H), 5.88 (s, 1H).

1. customThe reaction immediately became dark orange
2. extractionwas extracted with CH2Cl2 (3×150 mL)
3. washThe extract was washed with half saturated brine (1×150 mL)
4. filtrationfiltered through cotton
5. customthe solvent removed in vacuo

ORD record

ord-6560ef7fe087437598e19eb615d511fc

Source dataset

uspto-grants-1995_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05476933