Tetrahedron letters

A practical approach for the preparation of monofunctional azulenyl squaraine dye

W Pham, R Weissleder, CH Tung

文献索引：Pham, Wellington; Weissleder, Ralph; Tung, Ching-Hsuan Tetrahedron Letters, 2003 , vol. 44, # 20 p. 3975 - 3978

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被引用次数: 13

摘要

The synthesis of monofunctional azulenyl squaraine dye NIRQ700 is described. The essential azulene intermediate 3, 1-(methoxycarbonyl)-2-methylazulene, was achieved via [8+ 2] cycloaddition between lactone 2, 2H-3-methoxycarbonyl-cyclohepta [b] furan-2-one, and the in situ generated vinyl ethers under high temperature and pressure conditions. Methylation on the cycloheptatriene ring of 2-methyl azulene 6 via Meisenheimer-type ...