(4aS,5R,8R,8aS)-8-(tert-butyldiphenylsilyloxy)-3-(7,8-dimethoxy-2-oxo-2H-chromen-3-ylcarbamoyl)-4a-hydroxy-4a,5,8,8a-tetrahydro-4H-benzo[e][1,2]oxazin-5-yl acetate 在
甲醇 、
potassium carbonate 作用下,
以71%的产率得到(4aS,5R,8R,8aS)-8-(tert-butyldiphenylsilyloxy)-N-(7,8-dimethoxy-2-oxo-2H-chromen-3-yl)-4a,5-dihydroxy-4a,5,8,8a-tetrahydro-4H-benzo[e][1,2]oxazine-3-carboxamide