2,5-dimethylbenzene-1,3-diol

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

Procedure: To ethyl 4-chloro-3-oxobutanoate (3.08 mL) was added sulfuric acid (8.10 mL) at 0° C., then was added 2,5-dimethylbenzene-1,3-diol (3.0 g) in several portions at 0° C. The mixture was warmed to room temperature and stirred at room temperature for 2 h. The reaction mixture was poured into water under stirring at 0° C. The precipitate was collected by filtration and washed with hexane to give a solid. The solid was added to 1N NaOH (40 mL) at room temperature. The mixture was stirred at 100° C. for 1 h. After cooling, the reaction mixture was acidified with 6 N HCl (7.0 mL). The mixture was extracted with EtOAc. The organic layer was washed with brine, dried over MgSO4, and concentrated in vacuo to give the crude product. To a mixture of the crude product and MeOH (50 mL) was added H2SO4 (0.057 mL). The mixture was stirred at 60° C. for 2 h. The mixture was concentrated. The residue was neutralized with saturated aqueous NaHCO3 and extracted with EtOAc. The organic layer was washed with brine, dried over MgSO4, and concentrated in vacuo. The residue was purified by silica gel column chromatography (EtOAc/hexane) to give the title compound (865 mg). under stirring at 0° C The precipitate was collected by filtration washed with hexane to give a solid The mixture was stirred at 100° C. for 1 h After cooling The mixture was extracted with EtOAc The organic layer was washed with brine dried over MgSO4 concentrated in vacuo to give the crude product The mixture was stirred at 60° C. for 2 h The mixture was concentrated extracted with EtOAc The organic layer was washed with brine dried over MgSO4 concentrated in vacuo The residue was purified by silica gel column chromatography (EtOAc/hexane)

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

Procedure: To ethyl 4-chloro-3-oxobutanoate (3.08 mL) was added sulfuric acid (8.10 mL) at 0° C., then was added 2,5-dimethylbenzene-1,3-diol (3.0 g) in several portions at 0° C. The mixture was warmed to room temperature and stirred at room temperature for 2 h. The reaction mixture was poured into water under stirring at 0° C. The precipitate was collected by filtration and washed with hexane to give a solid. The solid was added to 1N NaOH (40 mL) at room temperature. The mixture was stirred at 100° C. for 1 h. After cooling, the reaction mixture was acidified with 6 N HCl (7.0 mL). The mixture was extracted with EtOAc. The organic layer was washed with brine, dried over MgSO4, and concentrated in vacuo to give the crude product. To a mixture of the crude product and MeOH (50 mL) was added H2SO4 (0.057 mL). The mixture was stirred at 60° C. for 2 h. The mixture was concentrated. The residue was neutralized with saturated aqueous NaHCO3 and extracted with EtOAc. The organic layer was washed with brine, dried over MgSO4, and concentrated in vacuo. The residue was purified by silica gel column chromatography (EtOAc/hexane) to give the title compound (865 mg). under stirring at 0° C The precipitate was collected by filtration washed with hexane to give a solid The mixture was stirred at 100° C. for 1 h After cooling The mixture was extracted with EtOAc The organic layer was washed with brine dried over MgSO4 concentrated in vacuo to give the crude product The mixture was stirred at 60° C. for 2 h The mixture was concentrated extracted with EtOAc The organic layer was washed with brine dried over MgSO4 concentrated in vacuo The residue was purified by silica gel column chromatography (EtOAc/hexane)

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

Procedure: 13.8 g. of 2,5-dimethyl resorcinol were dissolved in a mixed solution comprising 70 ml of isopropyl ether and 5 ml of concentrated sulfuric acid. Then, 10 g. of 4-methyl-3-pentene-2-ol were added dropwise to the solution at the temperature of about 60° C. for about 30 minutes. The resulting solution was cooled, and washed with water, with 1 N sodium hydroxide solution, and again with water and then dried over magnesium sulfate. The solvent was distilled off under reduced pressure. The residue was recrystallized from ether/n-hexane, to obtain 13.2 g. (yield: 60%) of the subject compound. Melting point: 88°-89° C. The resulting solution was cooled washed with water, with 1 N sodium hydroxide solution again with water and then dried over magnesium sulfate The solvent was distilled off under reduced pressure The residue was recrystallized from ether/n-hexane to obtain 13.2 g

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

Procedure: To a solution of 691 g. of 2,5-dimethylresorcinol in 1 l. of ethanol were added 348 g. of a 37% aqueous solution of formaldehyde and 0.5 ml. of 35% conc. hydrochloric acid as a catalyst. The resulting mixture was heated in the same manner as in the Synthesis example 1 and poured into 5 l. of a cold water to give a pale brown powdery resin. The resulting mixture was heated in the same manner as in the Synthesis example 1 poured into 5 l

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

Procedure: To ethyl 4-chloro-3-oxobutanoate (3.08 mL) was added sulfuric acid (8.10 mL) at 0° C., then was added 2,5-dimethylbenzene-1,3-diol (3.0 g) in several portions at 0° C. The mixture was warmed to room temperature and stirred at room temperature for 2 h. The reaction mixture was poured into water under stirring at 0° C. The precipitate was collected by filtration and washed with hexane to give a solid. The solid was added to 1N NaOH (40 mL) at room temperature. The mixture was stirred at 100° C. for 1 h. After cooling, the reaction mixture was acidified with 6 N HCl (7.0 mL). The mixture was extracted with EtOAc. The organic layer was washed with brine, dried over MgSO4, and concentrated in vacuo to give the crude product. To a mixture of the crude product and MeOH (50 mL) was added H2SO4 (0.057 mL). The mixture was stirred at 60° C. for 2 h. The mixture was concentrated. The residue was neutralized with saturated aqueous NaHCO3 and extracted with EtOAc. The organic layer was washed with brine, dried over MgSO4, and concentrated in vacuo. The residue was purified by silica gel column chromatography (EtOAc/hexane) to give the title compound (865 mg). under stirring at 0° C The precipitate was collected by filtration washed with hexane to give a solid The mixture was stirred at 100° C. for 1 h After cooling The mixture was extracted with EtOAc The organic layer was washed with brine dried over MgSO4 concentrated in vacuo to give the crude product The mixture was stirred at 60° C. for 2 h The mixture was concentrated extracted with EtOAc The organic layer was washed with brine dried over MgSO4 concentrated in vacuo The residue was purified by silica gel column chromatography (EtOAc/hexane)