2-ethyl-1,3-dithiane

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

Procedure: The same operation as in Example (36a) was performed using 2-ethyl-1,3-dithiane obtained in Example (39a) (3.51 g, 23.7 mmol), n-butyllithium (1.58 M solution in hexane, 18 mL, 28.3 mmol) and ethyl trifluoroacetate (4 mL, 33.6 mmol), to obtain 2.02 g of the title compound as a pale yellow oily substance (35%).

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

Procedure: The same operation as in Example (36a) was performed using 2-ethyl-1,3-dithiane obtained in Example (39a) (3.51 g, 23.7 mmol), n-butyllithium (1.58 M solution in hexane, 18 mL, 28.3 mmol) and ethyl trifluoroacetate (4 mL, 33.6 mmol), to obtain 2.02 g of the title compound as a pale yellow oily substance (35%).

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

Procedure: The same operation as in Example (36a) was performed using 2-ethyl-1,3-dithiane obtained in Example (39a) (3.51 g, 23.7 mmol), n-butyllithium (1.58 M solution in hexane, 18 mL, 28.3 mmol) and ethyl trifluoroacetate (4 mL, 33.6 mmol), to obtain 2.02 g of the title compound as a pale yellow oily substance (35%).

Conditions: temp:-78.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 2-Ethyl-1,3,-dithian (1,5 g) is dissolved in dried tetrahydrofuran (20 ml) and cooled to -78° C. To the mixture is added dropwise 1.6 N solution of n-butyllithium in n-hexane (6.5 ml) with stirring in argon gas flow. The mixture is stirred at -78° C. for 30 minutes. To the mixture is added dropwise a solution of 1-methyl-5-(3-chloropropyl)thio-1,2,3,4-tetrazole (1.9 g) in dried tetrahydrofuran (5 ml). After stirring at -78° C. for 1 hour, the mixture is stirred 4 hours while it is heated slowly to 0° C. The reaction mixture is poured into ice-water and extracted with ether. The ether solution is washed with water and saturated aqueous sodium chloride and dried over magnesium sulfate. After ether is distilled off, the residue is dissolved in acetonitrile (20 ml). Silver nitrate (7 g) and N-chlorosuccinimide (4.9 g) are dissolved in a mixture of water (40 ml) and acetonitrile (100 ml). To the mixture is added dropwise the dithian solution as above-mentioned with stirring at 0° C. in nitrogen gas flow. After stirring at 0° C. for 30 minutes, the mixture is heated to room temperature and further stirred for 30 minutes. The reaction mixture is diluted with water and extracted with chloroform. The chloroform solution is washed with water and saturated aqueous sodium chloride and dried over magnesium sulfate. After chloroform is distilled off, the residue is purified by column chromatography (Kieselgel 60) and eluted with benzene-ether (10:1) to give 1-methyl-5-(3-propionylpropyl)thio-1,2,3,4-tetrazole (0.3 g) as colorless liquid, nD25 =1.5042 The mixture is stirred at -78° C. for 30 minutes After stirring at -78° C. for 1 hour the mixture is stirred 4 hours while it is heated slowly to 0° C extracted with ether The ether solution is washed with water and saturated aqueous sodium chloride dried over magnesium sulfate After ether is distilled off the residue is dissolved in acetonitrile (20 ml) Silver nitrate (7 g) and N-chlorosuccinimide (4.9 g) are dissolved in a mixture of water (40 ml) and acetonitrile (100 ml) To the mixture is added dropwise the dithian solution as above-mentioned with stirring at 0° C. in nitrogen gas flow After stirring at 0° C. for 30 minutes the mixture is heated to room temperature further stirred for 30 minutes The reaction mixture is diluted with water extracted with chloroform The chloroform solution is washed with water and saturated aqueous sodium chloride dried over magnesium sulfate After chloroform is distilled off the residue is purified by column chromatography (Kieselgel 60) eluted with benzene-ether (10:1)

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

Procedure: The same operation as in Example (36a) was performed using 2-ethyl-1,3-dithiane obtained in Example (39a) (3.51 g, 23.7 mmol), n-butyllithium (1.58 M solution in hexane, 18 mL, 28.3 mmol) and ethyl trifluoroacetate (4 mL, 33.6 mmol), to obtain 2.02 g of the title compound as a pale yellow oily substance (35%).