(2S,3S,4R)-N"-cyano-N-(6-nitro-3,4-dihydro-3-hydroxy-2-methyl-2-dimethoxymethyl-2H-benzopyran-4-yl)-N'-(3,4-dimethoxybenzyl)guanidine 在
copper diacetate sodium tetrahydroborate 作用下,
以
甲醇 为溶剂,
以85%的产率得到(2S,3S,4R)-N''-cyano-N-(6-amino-3,4-dihydro-3-hydroxy-2-methyl-2-dimethoxymethyl-2H-benzopyran-4-yl)-N'-(3,4-dimethoxybenzyl)guanidine