ethyl 2-(4-oxo-2-sulfanylidene-1,3-thiazolidin-3-yl)acetate

Conditions: temp:25.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 5-(3-(Tributylstannyl)phenyl)furan-2-carbaldehyde (7 mg, 0.015 mmol) and ethyl-2-(4-oxo-2-thioxothiazolidin-3-yl)acetate (3.5 mg, 0.016 mmol) synthesized by the same method as in Example 1 were dissolved in dichloromethane (2 mL), piperidine (5 μL) was added thereto, and the mixture was stirred at room temperature (25° C.) overnight. After the reaction was completed the solvent was removed by evaporation under reduced pressure, and the residue was subjected to silica gel column chromatography using ethyl acetate/hexane (3/7 (volume ratio)) as an eluent, to give labeling precursor 1 in a yield of 6 mg (yield 56.6%). was removed by evaporation under reduced pressure to give labeling precursor 1 in a yield of 6 mg (yield 56.6%)

Conditions: temp:25.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 5-(3-(Tributylstannyl)phenyl)furan-2-carbaldehyde (7 mg, 0.015 mmol) and ethyl-2-(4-oxo-2-thioxothiazolidin-3-yl)acetate (3.5 mg, 0.016 mmol) synthesized by the same method as in Example 1 were dissolved in dichloromethane (2 mL), piperidine (5 μL) was added thereto, and the mixture was stirred at room temperature (25° C.) overnight. After the reaction was completed the solvent was removed by evaporation under reduced pressure, and the residue was subjected to silica gel column chromatography using ethyl acetate/hexane (3/7 (volume ratio)) as an eluent, to give labeling precursor 1 in a yield of 6 mg (yield 56.6%). was removed by evaporation under reduced pressure to give labeling precursor 1 in a yield of 6 mg (yield 56.6%)

Conditions: temp:25.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 5-(3-Iodophenyl)furan-2-carbaldehyde (30 mg, 0.1 mmol) and ethyl-2-(4-oxo-2-thioxothiazolidin-3-yl)acetate (22 mg, 0.1 mmol) were dissolved in dichloromethane (7 mL), piperidine (20 μL) was added thereto, and the mixture was stirred at room temperature (25° C.) for 3 hours. After the reaction was completed the solvent was removed by evaporation under reduced pressure, and the residue was subjected to silica gel column chromatography using ethyl acetate/hexane (3/7 (volume ratio)) as an eluent, to give the target compound 1 in a yield of 38 mg (yield 76.2%). was removed by evaporation under reduced pressure

Conditions: temp:25.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 5-(3-Iodophenyl)furan-2-carbaldehyde (30 mg, 0.1 mmol) and ethyl-2-(4-oxo-2-thioxothiazolidin-3-yl)acetate (22 mg, 0.1 mmol) were dissolved in dichloromethane (7 mL), piperidine (20 μL) was added thereto, and the mixture was stirred at room temperature (25° C.) for 3 hours. After the reaction was completed the solvent was removed by evaporation under reduced pressure, and the residue was subjected to silica gel column chromatography using ethyl acetate/hexane (3/7 (volume ratio)) as an eluent, to give the target compound 1 in a yield of 38 mg (yield 76.2%). was removed by evaporation under reduced pressure

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

Procedure: Separately, glycine ethyl ester hydrochloride (140 mg, 1 mmol) and bis(carboxymethyl) trithiocarbonate (224 mg, 1 mmol) were dissolved in 2-propanol (6 mL), triethylamine (0.6 mL) was added thereto, and the mixture was heated to reflux for 1 hour while stirring. After the reaction was completed the solvent was removed by evaporation under reduced pressure, and the residue was subjected to silica gel column chromatography using ethyl acetate/hexane (1/1 (volume ratio)) as an eluent, to give ethyl-2-(4-oxo-2-thioxothiazolidin-3-yl)acetate in a yield of 177 mg (yield 80.8%). the mixture was heated to reflux for 1 hour was removed by evaporation under reduced pressure

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

Procedure: To 30 ml of an ethanol solution of 13.0 g of the intermediate product obtained in Preparative Example 2, viz., 2-ethylmercapto-3-ethylbenzothiazolium p-toluenesulfonate, was added 4.4 g of 3-carboethoxymethylrhodanine, while stirring the mixture at room temperature (about 20° C.), 6.1 g of triethylamine was added dropwise to the solution over a 3 minute period, and thereafter the resultant mixture was refluxed for 10 minutes. After cooling the reaction mixture, precipitates formed were recovered by filtration and recrystallized from a mixture of chloroform and ethanol to provide 1.1 g of 3-carboethoxymethyl-5-(3-ethylbenzothiazolylidene)rhodanine (melting point 250° to 252° C.). was added dropwise to the solution over a 3 minute period After cooling the reaction mixture precipitates formed were recovered by filtration recrystallized from a mixture of chloroform and ethanol

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

Procedure: To 30 ml of an ethanol solution of 13.0 g of the intermediate product obtained in Preparative Example 2, viz., 2-ethylmercapto-3-ethylbenzothiazolium p-toluenesulfonate, was added 4.4 g of 3-carboethoxymethylrhodanine, while stirring the mixture at room temperature (about 20° C.), 6.1 g of triethylamine was added dropwise to the solution over a 3 minute period, and thereafter the resultant mixture was refluxed for 10 minutes. After cooling the reaction mixture, precipitates formed were recovered by filtration and recrystallized from a mixture of chloroform and ethanol to provide 1.1 g of 3-carboethoxymethyl-5-(3-ethylbenzothiazolylidene)rhodanine (melting point 250° to 252° C.). was added dropwise to the solution over a 3 minute period After cooling the reaction mixture precipitates formed were recovered by filtration recrystallized from a mixture of chloroform and ethanol

Conditions: temp:25.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 5-(3-(Tributylstannyl)phenyl)furan-2-carbaldehyde (7 mg, 0.015 mmol) and ethyl-2-(4-oxo-2-thioxothiazolidin-3-yl)acetate (3.5 mg, 0.016 mmol) synthesized by the same method as in Example 1 were dissolved in dichloromethane (2 mL), piperidine (5 μL) was added thereto, and the mixture was stirred at room temperature (25° C.) overnight. After the reaction was completed the solvent was removed by evaporation under reduced pressure, and the residue was subjected to silica gel column chromatography using ethyl acetate/hexane (3/7 (volume ratio)) as an eluent, to give labeling precursor 1 in a yield of 6 mg (yield 56.6%). was removed by evaporation under reduced pressure to give labeling precursor 1 in a yield of 6 mg (yield 56.6%)

Conditions: temp:25.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 5-(3-Iodophenyl)furan-2-carbaldehyde (30 mg, 0.1 mmol) and ethyl-2-(4-oxo-2-thioxothiazolidin-3-yl)acetate (22 mg, 0.1 mmol) were dissolved in dichloromethane (7 mL), piperidine (20 μL) was added thereto, and the mixture was stirred at room temperature (25° C.) for 3 hours. After the reaction was completed the solvent was removed by evaporation under reduced pressure, and the residue was subjected to silica gel column chromatography using ethyl acetate/hexane (3/7 (volume ratio)) as an eluent, to give the target compound 1 in a yield of 38 mg (yield 76.2%). was removed by evaporation under reduced pressure

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

Procedure: Separately, glycine ethyl ester hydrochloride (140 mg, 1 mmol) and bis(carboxymethyl) trithiocarbonate (224 mg, 1 mmol) were dissolved in 2-propanol (6 mL), triethylamine (0.6 mL) was added thereto, and the mixture was heated to reflux for 1 hour while stirring. After the reaction was completed the solvent was removed by evaporation under reduced pressure, and the residue was subjected to silica gel column chromatography using ethyl acetate/hexane (1/1 (volume ratio)) as an eluent, to give ethyl-2-(4-oxo-2-thioxothiazolidin-3-yl)acetate in a yield of 177 mg (yield 80.8%). the mixture was heated to reflux for 1 hour was removed by evaporation under reduced pressure

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

Procedure: To 30 ml of an ethanol solution of 13.0 g of the intermediate product obtained in Preparative Example 2, viz., 2-ethylmercapto-3-ethylbenzothiazolium p-toluenesulfonate, was added 4.4 g of 3-carboethoxymethylrhodanine, while stirring the mixture at room temperature (about 20° C.), 6.1 g of triethylamine was added dropwise to the solution over a 3 minute period, and thereafter the resultant mixture was refluxed for 10 minutes. After cooling the reaction mixture, precipitates formed were recovered by filtration and recrystallized from a mixture of chloroform and ethanol to provide 1.1 g of 3-carboethoxymethyl-5-(3-ethylbenzothiazolylidene)rhodanine (melting point 250° to 252° C.). was added dropwise to the solution over a 3 minute period After cooling the reaction mixture precipitates formed were recovered by filtration recrystallized from a mixture of chloroform and ethanol