2,5-dimethyl-1,4-dithiane-2,5-diol

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

Procedure: Next, 1.4 mL of triethylamine was added dropwise to a 10 mL ethanol solution of 0.9 g of 2,5-dihydroxy-2,5-dimethyl-1,4-dithiane, and the system was stirred for 30 minutes at room temperature. To this was added at room temperature a 10 mL ethanol solution of the 1-chloro-2-formyl-3,4-dihydronaphthalene obtained previously, and the system was refluxed under heating overnight. After the reaction, reduced-pressure solvent distillation was performed, first water and then 2M a sodium hydroxide aqueous solution were added under ice cooling, and extraction was performed with ethyl acetate. The organic layer was washed first with a saturated ammonium chloride aqueous solution and then with saturated brine, dried with magnesium sulfate, and subjected to reduced-pressure solvent distillation, and the residue was refined by silica gel column chromatography (20% ethyl acetate/hexane) and then recrystallized with ethanol to obtain 1.6 g of 2-acetyl-4,5-dihydro-6,8-dimethylnaphtho[1,2-b]thiophene (Table 6-1) in the form of yellow crystals. obtained previously the system was refluxed under heating overnight After the reaction, reduced-pressure solvent distillation extraction The organic layer was washed first with a saturated ammonium chloride aqueous solution with saturated brine, dried with magnesium sulfate subjected to reduced-pressure solvent distillation recrystallized with ethanol

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

Procedure: Next, 1.4 mL of triethylamine was added dropwise to a 10 mL ethanol solution of 0.9 g of 2,5-dihydroxy-2,5-dimethyl-1,4-dithiane, and the system was stirred for 30 minutes at room temperature. To this was added at room temperature a 10 mL ethanol solution of the 1-chloro-2-formyl-3,4-dihydronaphthalene obtained previously, and the system was refluxed under heating overnight. After the reaction, reduced-pressure solvent distillation was performed, first water and then 2M a sodium hydroxide aqueous solution were added under ice cooling, and extraction was performed with ethyl acetate. The organic layer was washed first with a saturated ammonium chloride aqueous solution and then with saturated brine, dried with magnesium sulfate, and subjected to reduced-pressure solvent distillation, and the residue was refined by silica gel column chromatography (20% ethyl acetate/hexane) and then recrystallized with ethanol to obtain 1.6 g of 2-acetyl-4,5-dihydro-6,8-dimethylnaphtho[1,2-b]thiophene (Table 6-1) in the form of yellow crystals. obtained previously the system was refluxed under heating overnight After the reaction, reduced-pressure solvent distillation extraction The organic layer was washed first with a saturated ammonium chloride aqueous solution with saturated brine, dried with magnesium sulfate subjected to reduced-pressure solvent distillation recrystallized with ethanol

Conditions: temp:60.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 90.1 g (0.5 mol) of 2,5-dihydroxy-2,5-dimethyl-1,4-dithiane are initially introduced into 100 ml of absolute tetrahydrofuran. 1.0 g of piperidine is then added, and 94.7 g (0.945 mol) of methyl acrylate are added dropwise at 10°-15° C, during which process another two portions of 0.5 g of piperidine are added at the same time. The mixture is subsequently stirred for 60 minutes at 60° C. It is allowed to cool and introduced into 500 ml of water. are added at the same time to cool

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

Procedure: Next, 1.4 mL of triethylamine was added dropwise to a 10 mL ethanol solution of 0.9 g of 2,5-dihydroxy-2,5-dimethyl-1,4-dithiane, and the system was stirred for 30 minutes at room temperature. To this was added at room temperature a 10 mL ethanol solution of the 1-chloro-2-formyl-3,4-dihydronaphthalene obtained previously, and the system was refluxed under heating overnight. After the reaction, reduced-pressure solvent distillation was performed, first water and then 2M a sodium hydroxide aqueous solution were added under ice cooling, and extraction was performed with ethyl acetate. The organic layer was washed first with a saturated ammonium chloride aqueous solution and then with saturated brine, dried with magnesium sulfate, and subjected to reduced-pressure solvent distillation, and the residue was refined by silica gel column chromatography (20% ethyl acetate/hexane) and then recrystallized with ethanol to obtain 1.6 g of 2-acetyl-4,5-dihydro-6,8-dimethylnaphtho[1,2-b]thiophene (Table 6-1) in the form of yellow crystals. obtained previously the system was refluxed under heating overnight After the reaction, reduced-pressure solvent distillation extraction The organic layer was washed first with a saturated ammonium chloride aqueous solution with saturated brine, dried with magnesium sulfate subjected to reduced-pressure solvent distillation recrystallized with ethanol