1,2,3,4-tetrahydronaphthalene-1,4-diol

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 1,4-dihydroxy-tetralin (1.640 g, 0.010 mol) in dichloromethane (50 ml) was added titanium tetrachloride (5.69 g, 0.03 mol). Then 1,1-dichlorodimethyl ether (1.73 g, 0.015 mol) was added dropwise under vigorous stirring and the reaction mixture stirred for another 3 h at room temperature. Finally 5% hydrochloric acid (10 ml) was added under ice-cooling. The organic phase was separated and the residual aqueous phase repeatedly extracted with ether. The combined organic phases are washed with saturated saline solution, dried over sodium sulfate and evaporated under vacuum. The residue was crystallized from benzene or alternatively submitted to flash chromatography on silica gel with benzene/ethylacetate 85:15 to afford pure title compound in about 60% yield (1.080 g), m.p. 145° C. the reaction mixture stirred for another 3 h at room temperature cooling The organic phase was separated the residual aqueous phase repeatedly extracted with ether The combined organic phases are washed with saturated saline solution dried over sodium sulfate evaporated under vacuum The residue was crystallized from benzene

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 1,4-dihydroxytetralin (1.640 g, 10 mM), in dichloromethane (50 ml) was added titanium tetrachloride (5.69 g, 30 mM). Then 1,1-dichlorodimethyl ether (1.73 g, 15 mM) was added dropwise under vigorous stirring and the reaction mixture stirred for another 3 h at room temperature. Finally 5% hydrochloric acid (10 ml) was added under ice-cooling. The organic phase was separated and the residual aqueous phase repeatedly extracted with ether. The combined organic phases are washed with saturated saline solution, dried over sodium sulfate and evaporated under vacuum. The residue was crystallized from benzene or alternatively submitted to flash chromatography on silica gel with benzene ethylacetate 85:15, to afford pure title compound in about 60% yield (1.080 g), m.p. 145° C. the reaction mixture stirred for another 3 h at room temperature cooling The organic phase was separated the residual aqueous phase repeatedly extracted with ether The combined organic phases are washed with saturated saline solution dried over sodium sulfate evaporated under vacuum The residue was crystallized from benzene

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 1,4-naphthoquinone (10 g, 63.3 mM) in glacial acetic acid were added platinum oxide (0.75 g, 3.3 mM) and the mixture was hydrogenated in a Parr apparatus under a pressure of 30-40 psi for about 24 h at room temperature. The catalyst was filtered off, the acetic acid was evaporated under vacuum, the residue was dissolved in hot water (200 ml) and the solution cooled to give crystalline 1,4-dihydroxytetralin in 58.3% yield (4.0 g). The catalyst was filtered off the acetic acid was evaporated under vacuum the residue was dissolved in hot water (200 ml) the solution cooled