proline dl-form → HCID 53253006, compound

Participants

Reaction Steps

A mixture of 5.40 g of (3,3,4,4,5,5,6,6,6-nonafluorohexylsulfonyl)acetonitrile, 60 ml of toluene, 0.18 g of DL-proline and 2.77 g of 1,4-cyclohexanedione monoethylene ketal was heated and stirred for 3 hours under the reflux condition. After 40 ml of toluene was distilled off, the reaction mixture was cooled to room temperature. The mixture was cooled to 0° C. and then 0.61 g of sodium borohydride was added thereto. To the reaction mixture was added 3 ml of N,N-dimethylformamide. The mixture was stirred at room temperature for 6 hours and then cooled to 0° C. Thereto 50 ml of water and 50 ml of ethyl acetate were added. While the reaction mixture was stirred, 20 ml of an aqueous 1N hydrochloric acid solution was added dropwise, followed by extraction with 100 ml of ethyl acetate twice. An organic layer was washed with 100 ml of an aqueous saturated sodium hydrogen carbonate solution, 100 ml of an aqueous saturated sodium chloride solution and 100 ml of water, dried over sodium sulfate, filtered, and concentrated under reduced pressure. The residue was dissolve to 14 ml of acetic acid and 6 ml of water. The mixture was heated to 100° C. and stirred for 8 hours. After the reaction mixture was cooled to room temperature, 100 ml of ethyl acetate was added thereto. The mixture was added slowly into 100 ml of an aqueous saturated sodium hydrogen carbonate solution. The solution was stirred for 1 hour, followed by extraction with 100 ml of ethyl acetate twice. Organic layers were combined, washed with 100 ml of an aqueous saturated sodium hydrogen carbonate solution and 100 ml of an aqueous saturated sodium chloride solution, dried over sodium sulfate, filtered, and concentrated under reduced pressure. The residue was subjected to silica gel column chromatography to obtain 2.94 g of 2-(4-oxocyclohexyl)-2-(3,3,4,4,5,5,6,6,6-nonafluorohexylsulfonyl)acetonitrile (hereinafter, referred to as the present compound (62)) represented by the formula:

Provenance & Evidence