A practical approach for the preparation of monofunctional azulenyl squaraine dye
A practical approach for the preparation of monofunctional azulenyl squaraine dye
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DOI：
10.1016/s0040-4039(03)00819-0
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发表时间：
2003-05-12
影响因子：
1.8
通讯作者：
Tung, CH
中科院分区：
文献类型：
--
作者：
Pham, W;Weissleder, R;Tung, CH
The synthesis of monofunctional azulenyl squaraine dye NIRQ(700) 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 intermediate following Schrott's method formed the carboxylic acid intermediate 9, 3-(2-methyl-azulen-4-yl)-propionic acid. Condensation of 9 with squaric acid provided the title compound NIRQ(700) at moderate yields. The non-fluorescent squaraine dye NIRQ(700) absorbed in a 600-700 nm range and potentially can be used to quench a number of available NIR fluorochromes in order to extend the spectrum of biological quenching assays. (C) 2003 Elsevier Science Ltd. All rights reserved.
