13 g 3 19 mmol was added at room temperature after stirring the mixture at the same temperature for 11 hours the solvent was distilled off under reduced pressure the residue was dissolved in dcm and insoluble matter was filtered off the filtrate was concentrated in vacuo the residue was purified by flash column chromatography yamazen hi flash u2122 column silicagel l size 20 ml min gradient 10 to 50 acoet in n heptane to afford the title compound as white solids 532 mg 2 61 mmol 1 h nmr 400 mhz cdcl 3 u03b4 ppm 3 57 t j 12 4 hz 2h 6 74 6 94 m 1h 6 95 7 08 m 1h ammonium acetate 427 g 55 4 mmol was added to a solution of the product obtained in production example 1 2 377 mg 1 85 mmol in isopropanol 16 ml at room temperature and the mixture was refluxed for 30 min sodium cyanoborohydride 348 mg 5 54 mmol was added to the reaction mixture and stirred under reflux for 7 hours after cooling to room temperature acoet and 2n naoh were added to the reaction mixture and the layers were separated the organic layer was concentrated in vacuo water was added to the residue and partitioned between acoet and 1n hcl the aqueous layer was basified with 2n naoh and extracted with acoet the organic layer was dried over na2so4 evaporated and dried to afford the title compound 210 mg 1 02 mmol 1 h nmr 400 mhz cdcl 3 u03b4 ppm 3 26 3 55 m 2h 4 59 dd j 13 3 5 3 hz 1h 6 61 6 86 m 2h to a dcm solution 10 ml of the product obtained.