2,3-DIHYDRO-1,4-BENZODIOXIN-2-ONE

Conditions: temp:0.00; pressure:0.00; stir:

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

Procedure: To a stirred solution of 120 grams of catechol and 10 grams of Aliquat® 336 (brand of tricaprylmethylammonium chloride, of General Mills Chemical Company of Minneapolis, Minnesota) at 80° C. is added ethyl chloroacetate (87 grams, 1 mole) over a one hour period. The reaction mass is stirred for one hour and then cooled. 1000 ml of dilute (5%) hydrochloric acid is added with stirring. The aqueous layer is discarded. The organic layer is washed twice with a minimum amount of water. The toluene is distilled off under reduced pressure to afford 119 grams of crude product. Recrystallization from ethanol afforded 92 grams of 1,4-benzodioxan-2-one. cooled is added with stirring The organic layer is washed twice with a minimum amount of water The toluene is distilled off under reduced pressure to afford 119 grams of crude product Recrystallization from ethanol

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

Procedure: 161.5 g (0.87 mole) of chloroacetic acid 2-hydroxyphenyl ester were dissolved in 300 ml of anhydrous dimethylformamide. 20.88 g (0.87 mole) of sodium hydride were added portion by portion with indirect ice refrigeration. After the ending of the addition, heating was carried out for 3 hours at 35° C. followed by hydrolysis in which the reaction mixture was distributed between 600 ml 1N hydrochloric acid and 600 ml diethyl ether. The organic phase was dried with sodium sulfate and was concentrated by evaporation. 117.6 g (90% of the theoretical amount) of raw 3-H-benzo-1,4-dioxin-2-one were obtained. The light-brown oil which was accumulated at first was crystallized in the course of time (melting point 45°-53° C.2). After the ending of the addition heating followed by hydrolysis in which the reaction mixture The organic phase was dried with sodium sulfate was concentrated by evaporation

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

Procedure: To a stirred solution of 120 grams of catechol and 10 grams of Aliquat® 336 (brand of tricaprylmethylammonium chloride, of General Mills Chemical Company of Minneapolis, Minnesota) at 80° C. is added ethyl chloroacetate (87 grams, 1 mole) over a one hour period. The reaction mass is stirred for one hour and then cooled. 1000 ml of dilute (5%) hydrochloric acid is added with stirring. The aqueous layer is discarded. The organic layer is washed twice with a minimum amount of water. The toluene is distilled off under reduced pressure to afford 119 grams of crude product. Recrystallization from ethanol afforded 92 grams of 1,4-benzodioxan-2-one. cooled is added with stirring The organic layer is washed twice with a minimum amount of water The toluene is distilled off under reduced pressure to afford 119 grams of crude product Recrystallization from ethanol

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

Procedure: To a stirred solution of 120 grams of catechol and 10 grams of Aliquat® 336 (brand of tricaprylmethylammonium chloride, of General Mills Chemical Company of Minneapolis, Minnesota) at 80° C. is added ethyl chloroacetate (87 grams, 1 mole) over a one hour period. The reaction mass is stirred for one hour and then cooled. 1000 ml of dilute (5%) hydrochloric acid is added with stirring. The aqueous layer is discarded. The organic layer is washed twice with a minimum amount of water. The toluene is distilled off under reduced pressure to afford 119 grams of crude product. Recrystallization from ethanol afforded 92 grams of 1,4-benzodioxan-2-one. cooled is added with stirring The organic layer is washed twice with a minimum amount of water The toluene is distilled off under reduced pressure to afford 119 grams of crude product Recrystallization from ethanol

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

Procedure: To a stirred solution of 120 grams of catechol and 10 grams of Aliquat® 336 (brand of tricaprylmethylammonium chloride, of General Mills Chemical Company of Minneapolis, Minn.) at 80° C. is added ethyl chloroacetate (87 grams, 1 mole) over a one hour period. The reaction mass is stirred for one hour and then cooled. 1,000 ml of dilute (5%) hydrochloric acid is added with stirring. The aqueous layer is discarded. The organic layer is washed twice with a minimum amount of water. The toluene is distilled off under reduced pressure to afford 119 grams of crude product. Recrystallization from ethanol afforded 92 grams of 1,4-benzodioxan-2-one. cooled is added with stirring The organic layer is washed twice with a minimum amount of water The toluene is distilled off under reduced pressure to afford 119 grams of crude product Recrystallization from ethanol

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

Procedure: To a stirred solution of 120 grams of catechol and 10 grams of Aliquat® 336 (brand of tricaprylmethylammonium chloride, of General Mills Chemical Company of Minneapolis, Minnesota) at 80° C. is added ethyl chloroacetate (87 grams, 1 mole) over a one hour period. The reaction mass is stirred for one hour and then cooled. 1000 ml of dilute (5%) hydrochloric acid is added with stirring. The aqueous layer is discarded. The organic layer is washed twice with a minimum amount of water. The toluene is distilled off under reduced pressure to afford 119 grams of crude product. Recrystallization from ethanol afforded 92 grams of 1,4-benzodioxan-2-one. cooled is added with stirring The organic layer is washed twice with a minimum amount of water The toluene is distilled off under reduced pressure to afford 119 grams of crude product Recrystallization from ethanol

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

Procedure: To a stirred solution of 120 grams of catechol and 10 grams of Aliquat® 336 (brand of tricaprylmethylammonium chloride, of General Mills Chemical Company of Minneapolis, Minn.) at 80° C. is added ethyl chloroacetate (87 grams, 1 mole) over a one hour period. The reaction mass is stirred for one hour and then cooled. 1,000 ml of dilute (5%) hydrochloric acid is added with stirring. The aqueous layer is discarded. The organic layer is washed twice with a minimum amount of water. The toluene is distilled off under reduced pressure to afford 119 grams of crude product. Recrystallization from ethanol afforded 92 grams of 1,4-benzodioxan-2-one. cooled is added with stirring The organic layer is washed twice with a minimum amount of water The toluene is distilled off under reduced pressure to afford 119 grams of crude product Recrystallization from ethanol

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

Procedure: To a stirred solution of 120 grams of catechol and 10 grams of Aliquat® 336 (brand of tricaprylmethylammonium chloride, of General Mills Chemical Company of Minneapolis, Minnesota) at 80° C. is added ethyl chloroacetate (87 grams, 1 mole) over a one hour period. The reaction mass is stirred for one hour and then cooled. 1000 ml of dilute (5%) hydrochloric acid is added with stirring. The aqueous layer is discarded. The organic layer is washed twice with a minimum amount of water. The toluene is distilled off under reduced pressure to afford 119 grams of crude product. Recrystallization from ethanol afforded 92 grams of 1,4-benzodioxan-2-one. cooled is added with stirring The organic layer is washed twice with a minimum amount of water The toluene is distilled off under reduced pressure to afford 119 grams of crude product Recrystallization from ethanol

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:-70.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: The mixture is warmed at room temperature, then heated to reflux for 2 hours. The organic phase is washed with water, 5% aqueous sodium hydroxyde and then with water. After drying on Na2SO4, the solvent is evaporated to dryness under vacuum and the crude material is crytallized from cyclohexane-Et2O to give 1,4-benzodioxan-2-one (10 g) m.p. 52°-54° C. A molar solution of DIBAH in toluene (73 ml) is added dropwise to a stirred solution of 1,4-benzodioxan-2-one (8.9 g) in dry toluene (100 ml), cooled at -70° C. during 40 minutes. Stirring at this temperature is continued for 15 minutes, then the excess reagent is destroyed by adding 2N-isopropanol in toluene (75 ml), under stirring, at -70°÷-60° C. The mixture is warmed at room temperature and treated with 30% NaH2PO4 aqueous solution (6 ml) and 25 g of anhydrous Na 2 SO4, for 4 hours, under stirring. The inorganic material is filtered out and the eluate is evaporated to dryness to give 8.2 g of 2-hydroxy-1,4-benzodioxan. A stirred solution of this δ-lactol (7.8 g) in ethanol (30 ml) is treated with a solution of cysteamine hydrochloride (7.36 g) and potassium acetate (6.5 g) in water (12 ml). Stirring is continued for 45 minutes, then a crystalline precipitate of 2-[(o-hydroxyphenoxy)methyl]thiazolidine (8.1 g) is obtained. M.p. 76°-78° C. the excess reagent is destroyed by adding 2N-isopropanol in toluene (75 ml) under stirring, at -70°÷-60° C The mixture is warmed at room temperature treated with 30% NaH2PO4 aqueous solution (6 ml) and 25 g of anhydrous Na 2 SO4, for 4 hours under stirring The inorganic material is filtered out the eluate is evaporated to dryness

Conditions: temp:-70.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: The mixture is warmed at room temperature, then heated to reflux for 2 hours. The organic phase is washed with water, 5% aqueous sodium hydroxyde and then with water. After drying on Na2SO4, the solvent is evaporated to dryness under vacuum and the crude material is crytallized from cyclohexane-Et2O to give 1,4-benzodioxan-2-one (10 g) m.p. 52°-54° C. A molar solution of DIBAH in toluene (73 ml) is added dropwise to a stirred solution of 1,4-benzodioxan-2-one (8.9 g) in dry toluene (100 ml), cooled at -70° C. during 40 minutes. Stirring at this temperature is continued for 15 minutes, then the excess reagent is destroyed by adding 2N-isopropanol in toluene (75 ml), under stirring, at -70°÷-60° C. The mixture is warmed at room temperature and treated with 30% NaH2PO4 aqueous solution (6 ml) and 25 g of anhydrous Na 2 SO4, for 4 hours, under stirring. The inorganic material is filtered out and the eluate is evaporated to dryness to give 8.2 g of 2-hydroxy-1,4-benzodioxan. A stirred solution of this δ-lactol (7.8 g) in ethanol (30 ml) is treated with a solution of cysteamine hydrochloride (7.36 g) and potassium acetate (6.5 g) in water (12 ml). Stirring is continued for 45 minutes, then a crystalline precipitate of 2-[(o-hydroxyphenoxy)methyl]thiazolidine (8.1 g) is obtained. M.p. 76°-78° C. the excess reagent is destroyed by adding 2N-isopropanol in toluene (75 ml) under stirring, at -70°÷-60° C The mixture is warmed at room temperature treated with 30% NaH2PO4 aqueous solution (6 ml) and 25 g of anhydrous Na 2 SO4, for 4 hours under stirring The inorganic material is filtered out the eluate is evaporated to dryness