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.CO>[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 methanol, were charged 0.16 ml of methanol containing 25 g of hydrochloric acid dissolved therein, 0.79 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 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 and 2N NaOH aqueous solution was added thereto to make the filtrate alkaline (pH 11). The resulting mixture was then extracted with ethyl acetate. The liquid extract was analyzed by GC and LC to show, as a product, 0.88 g of 2-methoxy-3,4-methylenedioxy-N-methylbenzylamino dimethylacetal (yield 56%) and 0.44 g of 2-methoxy-3,4-methylenedioxybenzyl alcohol (yield 44%), while 2-methoxy-3,4-methylenedioxybenzaldehyde of the starting material being not recognized (conversion rate:10%). The selectivity to the desired 2-methoxy-3,4-methylenedioxy-N-methylbenzylamino dimethylacetal was 56%.
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