1-甲基-2-******1-methyl-2-piperidinemethanol20845-34-5含量98.5%1-甲基-3-******1-methyl-3-piperidinemethanol7583-53-1含量98.5%1-甲基-4-******1-methyl-4-piperidinemethanol20691-89-8含量98.5%)