Hydrochloric Acid → 2-Methoxy-5,8-dihydronaphthalene-1,4-diol

Participants

Reaction Steps

A solution of 2-methoxy-4a,5,8,8a-tetrahydronaphthalene-1,4-dione (55, 542 mg, 2.82 mmol) in MeOH (50 mL) was purged with a stream of N2 for 5 min with stirring at rt. With continued N2 purging, solid K2CO3 (390 mg, 2.82 mmol, Baker) was added to the stirred solution. The solution immediately turned yellow. The reaction was allowed to stir for 15 min at rt under N2, after which it was brown. To this there was added a dilute HCl solution (10% concd HCl, 90% H2O, 50 mL) in one portion. The MeOH was removed in vacuo to give a colorless suspension. The suspended material was collected by filtration, washed with a dilute acid solution (as above, 4×6 mL) and dried in vacuo to yield a fluffy colorless solid (444 mg, 82%, pure by 1H NMR analysis (unstable on TLC)); mp 142.5°-144° C. (confirmed), lit. (Cavill et al., supra) 123°-124° C. (benzene/petroleum ether); 1H NMR (CDCl3) δ2.21 (m, 2H), 3.32 (m, 2H), 3.84 (s, 3H), 4.25 (s, 1H), 5.25 (s, 1H), 5.90 (m, 2H), 6.36 (s, 1H).

Provenance & Evidence