Cl.COC(OC)CNC.[CH3:10][O:11][C:12]1[C:19]2[O:20][CH2:21][O:22][C:18]=2[CH:17]=[CH:16][C:13]=1[CH:14]=[O:15].C([BH3-])#N.[Na+].[OH-].[Na+]>C(O)C>[CH3:10][O:11][C:12]1[C:19]2[O:20][CH2:21][O:22][C:18]=2[CH:17]=[CH:16][C:13]=1[CH2:14][OH:15]To 100 ml of ethanol, were charged 1.83 ml of ethanol containing 22.2 g of hydrochloric acid dissolved therein, 3.96 g of N-methylaminoacetaldehyde dimethylacetal, 1.0 g of 2-methoxy-3,4-methylenedioxybenzaldehyde, 0.35 g of sodium cyanoborohydride and 10 ml of ethanol, and they were stirred in an oil bath under a nitrogen stream at 70° C. for 2 hours. After the reaction was over, the reaction mixture was cooled to room temperature, made alkaline (pH 11) with 2N NaOH solution and extracted with ethyl acetate. The liquid extract was analyzed by GC and LC to show, as a product, 1.50 g of 2-methoxy-3,4-methylenedioxy-N-methylbenzylamino dimethylacetal (yield 95%) and 0.046 g of 2-methoxy-3,4-methylenedioxy benzylalcohol (yield 4.9%), while 2-methoxy-3,4-methylenedioxy benzaldehyde of the starting material not being recognized (conversion rate:100%). The selectivity to the desired 2-methoxy-3,4-methylenedioxy-N-methylbenzylamino dimethylacetal was 95%.
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