Efficient Synthesis of Tyrosine-Derived Marine Sponge Metabolites via Acylation of Amines with a Coumarin

Condensation of N-acetylglycine with aldehyde 15 in acetic anhydride gave acetamido coumarin
16. Hydrolysis to the enol coumarin 17 and reaction with hydroxylamine gave the oximino coumarin
18. Reaction of the oximino coumarin 18 with a range of nucleophiles gave the phenolic oximes in
excellent yield. The rates of acylation of histamine with the oximino coumarin 18 and methyl ester
9 were compared. Oxidative spirocyclization of three representative phenolic oximes with polymer-supported (diacetoxyiodo) benzene gave the spiroisoxazolines.

将N-乙酰甘氨酸与醛15在乙酸酐中进行缩合反应，得到乙酰氨基香豆素16。将其水解得到烯醇香豆素17，再与羟胺反应，生成肟基香豆素18。将肟基香豆素18与一系列亲核试剂进行反应，以优异的收率得到酚肟类化合物。对比了肟基香豆素18与甲酯9对组胺的酰化反应速率。将三种代表性酚肟与聚合物负载的二乙酰氧基碘苯（polymer-supported (diacetoxyiodo) benzene）进行氧化螺环化反应，得到螺异噁唑啉类产物。