In a three-necked flask, 5.7 g (0.05 mol) of trans-(R,R)-1,2-cyclohexanediamine and 200 mL of a solvent dichloromethane were added. After dissolving 2-hydroxy-3-methoxybenzaldehyde 8.15 g (0.1 mol) in 50 mL of dichloromethane, it was added dropwise to the stirred diamine solution. The reaction mixture was warmed to reflux, and the reaction was cooled for 1 h, and the microwave power was 200 W at 25 ° C, and the reaction was stirred for 40 min. After the reaction was stopped, the solvent was removed by rotary evaporation at 40 °C. Further, 200 mL of methanol was added to the reaction flask, and 6 g of sodium borohydride powder was slowly added in portions, and after completion, it was heated to reflux for 1 hour, and cooled to room temperature. Add 2 mol · L - 1 aqueous hydrochloric acid to a pH of about 2, then add a saturated aqueous solution of sodium bicarbonate to adjust the pH to about 10. Dichloromethane (3 × 100 mL) was added for extraction. The organic phase was dried over anhydrous magnesium sulfate and filtered and evaporated. The product was isolated on a silica gel column (ethyl acetate: petroleum ether = 1 : 10).