[BH4-].[Na+].[CH3:3][N:4]([CH3:23])[S:5](=[O:22])(=[O:21])[O:6][C:7]1[CH:12]=[C:11]([O:13][CH3:14])[C:10]([O:15][CH3:16])=[CH:9][C:8]=1[CH:17]=[CH:18][C:19]#[N:20].CO.Cl>C1COCC1.O>[CH3:23][N:4]([CH3:3])[S:5](=[O:21])(=[O:22])[O:6][C:7]1[CH:12]=[C:11]([O:13][CH3:14])[C:10]([O:15][CH3:16])=[CH:9][C:8]=1[CH2:17][CH2:18][C:19]#[N:20]Disperse 6.7 g (0.177 mol) of sodium borohydride in 150 ml of THF. Pour in dropwise a suspension of 18.4 g (0.059 mol) of 2-(2-cyanovinyl)-4,5-dimethoxyphenyl dimethylsulphamate in 200 ml of THF. Pour in dropwise 48 ml of methanol. Heat for 3 h at 50° C. and then cool and add 1 g (0.026 mol) of sodium borohydride. Heat the reaction mixture at 50° C. for 1 h and then stir overnight at ambient temperature. Hydrolyse by pouring into the reaction mixture 60 ml of aqueous 4N HCl solution while maintaining the temperature at approximately 20° C. Add 40 g of ice and 30 ml of water and then extract twice with 200 ml of ethyl acetate each time. The organic phase is washed with water and saturated aqueous NaCl solution and then dried over MgSO4, filtered and evaporated to dryness. 17.4 g of title product are obtained.
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