(Rac-trans)-1-tert-Butyl 3-methyl 4-(5,6-dimethoxy pyridin-2-yl)pyrrolidine-1,3-dicarboxylate(rac-trans)-1-tert-Butyl 3-methyl 4-(5,6-dimethoxypyridin-2-yl)pyrrolidine-1,3-dicarboxylate(rac-trans)-1-tert-Butyl 3-methyl 4-(5,6-dimethoxypyridin-2-yl)pyrrolidine-1,3-dicarboxylate