3,4-二羟基苯酰肼

反应条件: temp:0.00; pressure:0.00; stir:

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: 19.8 g (0.353 mol) of potassium hydroxide was dissolved in 5.1 ml of water and 830 ml of ethanol, and 39.6 g (0.236 mol) of 3,4-dihydroxybenzohydrazide and 99 ml (1.65 mol) of carbon disulfide was added thereto. The mixture was heated for 24 hours under reflux. The reaction solution was stirred for 1.5 hours under cooling with ice. The precipitated crystals were collected by filtration and washed with 200 ml of ethanol. The crystals were dissolved in 3 liter of water and adjusted to pH1.5 with 6N hydrochloric acid under cooling with ice. The solution was extracted with 1 liter of ethyl acetate and 400 ml of ethyl acetate. The organic layers were put together, washed twice with 300 ml of a saturated sodium chloride aqueous solution, dried over anhydrous magnesium sulfate and concentrated under reduced pressure to obtain 42.8 g (yield: 86.5%) of 2-mercapto-5-(3,4-dihydroxyphenyl)-1,3,4-oxadiazole. The mixture was heated for 24 hours under reflux under cooling with ice The precipitated crystals were collected by filtration washed with 200 ml of ethanol The crystals were dissolved in 3 liter of water under cooling with ice The solution was extracted with 1 liter of ethyl acetate and 400 ml of ethyl acetate washed twice with 300 ml of a saturated sodium chloride aqueous solution dried over anhydrous magnesium sulfate concentrated under reduced pressure

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: 10 g (178 mmol) of potassium hydroxide was dissolved in 400 ml of ethanol, and 20 g (119 mmol) of protocatechuhydrazide was added thereto under stirring at a temperature of at most 5° C. To this solution, 28.0 ml of carbon disulfide was dropwise added over a period of 10 minutes at a temperature of at most 10° C., and the mixture was stirred at a temperature of from 0 to 10° C. for 30 minutes. Then, the precipitates were collected by filtration, washed with ethanol and dried to obtain 25.3 g (yield: 75.3%) of potassium 3-protocatechuoyldithiocarbazate. the mixture was stirred at a temperature of from 0 to 10° C. for 30 minutes Then, the precipitates were collected by filtration washed with ethanol dried

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: 10 g (178 mmol) of potassium hydroxide was dissolved in 400 ml of ethanol, and 20 g (119 mmol) of protocatechuhydrazide was added thereto under stirring at a temperature of at most 5° C. To this solution, 28.0 ml of carbon disulfide was dropwise added over a period of 10 minutes at a temperature of at most 10° C., and the mixture was stirred at a temperature of from 0 to 10° C. for 30 minutes. Then, the precipitates were collected by filtration, washed with ethanol and dried to obtain 25.3 g (yield: 75.3%) of potassium 3-protocatechuoyldithiocarbazate. the mixture was stirred at a temperature of from 0 to 10° C. for 30 minutes Then, the precipitates were collected by filtration washed with ethanol dried

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: 120 g of 3,4-dihydroxybenzoic acid methyl ester was subjected to reaction with 340 ml of methanol and 340 ml of hydrazine hydrate over 3 days at room temperature. Then 340 ml of water was added thereto and the solvent was evaporated in vacuum. Addition of water and evaporation were repeated twice. Subsequently the product was crystallized from 340 ml of water. m.p. 260° C. (decomposed). the solvent was evaporated in vacuum Addition of water and evaporation Subsequently the product was crystallized from 340 ml of water

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: 120 g of 3,4-dihydroxybenzoic acid methyl ester was subjected to reaction with 340 ml of methanol and 340 ml of hydrazine hydrate over 3 days at room temperature. Then 340 ml of water was added thereto and the solvent was evaporated in vacuum. Addition of water and evaporation were repeated twice. Subsequently the product was crystallized from 340 ml of water. m.p. 260° C. (decomposed). the solvent was evaporated in vacuum Addition of water and evaporation Subsequently the product was crystallized from 340 ml of water

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: 10 g (178 mmol) of potassium hydroxide was dissolved in 400 ml of ethanol, and 20 g (119 mmol) of protocatechuhydrazide was added thereto under stirring at a temperature of at most 5° C. To this solution, 28.0 ml of carbon disulfide was dropwise added over a period of 10 minutes at a temperature of at most 10° C., and the mixture was stirred at a temperature of from 0° to 10° C. for 30 minutes. Then, the precipitates were collected by filtration, washed with ethanol and dried to obtain 25.3 g (yield: 75.3%) of potassium 3-protocatechuoyldithiocarbazate. the mixture was stirred at a temperature of from 0° to 10° C. for 30 minutes Then, the precipitates were collected by filtration washed with ethanol dried

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: 10 g (178 mmol) of potassium hydroxide was dissolved in 400 ml of ethanol, and 20 g (119 mmol) of protocatechuhydrazide was added thereto under stirring at a temperature of at most 5° C. To this solution, 28.0 ml of carbon disulfide was dropwise added over a period of 10 minutes at a temperature of at most 10° C., and the mixture was stirred at a temperature of from 0° to 10° C. for 30 minutes. Then, the precipitates were collected by filtration, washed with ethanol and dried to obtain 25.3 g (yield: 75.3%) of potassium 3-protocatechuoyldithiocarbazate. the mixture was stirred at a temperature of from 0° to 10° C. for 30 minutes Then, the precipitates were collected by filtration washed with ethanol dried

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: 19.8 g (0.353 mol) of potassium hydroxide was dissolved in 5.1 ml of water and 830 ml of ethanol, and 39.6 g (0.236 mol) of 3,4-dihydroxybenzohydrazide and 99 ml (1.65 mol) of carbon disulfide was added thereto. The mixture was heated for 24 hours under reflux. The reaction solution was stirred for 1.5 hours under cooling with ice. The precipitated crystals were collected by filtration and washed with 200 ml of ethanol. The crystals were dissolved in 3 liter of water and adjusted to pH1.5 with 6N hydrochloric acid under cooling with ice. The solution was extracted with 1 liter of ethyl acetate and 400 ml of ethyl acetate. The organic layers were put together, washed twice with 300 ml of a saturated sodium chloride aqueous solution, dried over anhydrous magnesium sulfate and concentrated under reduced pressure to obtain 42.8 g (yield: 86.5%) of 2-mercapto-5-(3,4-dihydroxyphenyl)-1,3,4-oxadiazole. The mixture was heated for 24 hours under reflux under cooling with ice The precipitated crystals were collected by filtration washed with 200 ml of ethanol The crystals were dissolved in 3 liter of water under cooling with ice The solution was extracted with 1 liter of ethyl acetate and 400 ml of ethyl acetate washed twice with 300 ml of a saturated sodium chloride aqueous solution dried over anhydrous magnesium sulfate concentrated under reduced pressure

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: 19.8 g (0.353 mol) of potassium hydroxide was dissolved in 5.1 ml of water and 830 ml of ethanol, and 39.6 g (0.236 mol) of 3,4-dihydroxybenzohydrazide and 99 ml (1.65 mol) of carbon disulfide was added thereto. The mixture was heated for 24 hours under reflux. The reaction solution was stirred for 1.5 hours under cooling with ice. The precipitated crystals were collected by filtration and washed with 200 ml of ethanol. The crystals were dissolved in 3 liter of water and adjusted to pH1.5 with 6N hydrochloric acid under cooling with ice. The solution was extracted with 1 liter of ethyl acetate and 400 ml of ethyl acetate. The organic layers were put together, washed twice with 300 ml of a saturated sodium chloride aqueous solution, dried over anhydrous magnesium sulfate and concentrated under reduced pressure to obtain 42.8 g (yield: 86.5%) of 2-mercapto-5-(3,4-dihydroxyphenyl)-1,3,4-oxadiazole. The mixture was heated for 24 hours under reflux under cooling with ice The precipitated crystals were collected by filtration washed with 200 ml of ethanol The crystals were dissolved in 3 liter of water under cooling with ice The solution was extracted with 1 liter of ethyl acetate and 400 ml of ethyl acetate washed twice with 300 ml of a saturated sodium chloride aqueous solution dried over anhydrous magnesium sulfate concentrated under reduced pressure

反应条件: temp:0.00; pressure:0.00; stir:

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: 19.52 ml (0.10 mol) of N-methyl-N-trimethylsilyltrifluoroacetamide was added to a suspension of 4.20 g (0.025 mol) of 3,4-dihydroxybenzoic acid, hydrazide in 25 ml of dry acetonitrile. Stirring was continued at room temperature until a clear solution was formed (40 minutes). After evaporation in vacuo at 30°-40° C., the residue was dissolved in 25 ml of dry dichloromethane. This solution was dropped into a stirred suspension of 5.72 g (25.0 mmol) of [[[(phenylmethoxy)carbonyl]hydrazino]carbonyl]chloride at 5° C. After stirring for 1 hour at 0° C., the mixture was evaporated in vacuo and the oily residue was stirred with ether containing 4 ml of methanol until it became crystalline; yield after washing with ether and drying in vacuo: 8.77 g. was continued at room temperature until a clear solution was formed (40 minutes) After evaporation in vacuo at 30°-40° C. the residue was dissolved in 25 ml of dry dichloromethane After stirring for 1 hour at 0° C. the mixture was evaporated in vacuo the oily residue was stirred with ether containing 4 ml of methanol until it yield after washing with ether drying in vacuo