6-Methoxy-benzofuran-2-carboxylic acid (2R,3S,5R)-3-acetoxy-5-(5-methyl-2,4-dioxo-3,4-dihydro-2H-pyrimidin-1-yl)-tetrahydro-furan-2-ylmethyl ester 在
甲醇 、
silica gel 作用下,
生成 、 (4bS,4cR,8aR,8bS)-8-((2R,4S,5R)-4-Acetoxy-5-hydroxymethyl-tetrahydro-furan-2-yl)-2-methoxy-4c-methyl-5,7-dioxo-4c,5,6,7,8,8a-hexahydro-4bH-9-oxa-6,8-diaza-benzo[3,4]cyclobuta[1,2-a]indene-8b-carboxylic acid methyl ester