Azobenzene dye-coupled quadruply hydrogen-bonding modules as colorimetric indicators for supramolecular interactions

作者：Zhang Yagang; Zimmerman Steven C^*

来源：Beilstein Journal of Organic Chemistry, 2012, 8: 486-495.

DOI：10.3762/bjoc.8.55

• azobenzene dye
• colorimetric indicators
• 7-deazaguanine urea (DeUG)
• 2,7-diamido-1,8-naphthyridine (DAN)
• polymer
• quadruply hydrogen bonding
• supramolecular

The facile coupling of azobenzene dyes to the quadruply hydrogen-bonding modules 2,7-diamido-1,8-naphthyridine (DAN) and 7-deazaguanine urea (DeUG) is described. The coupling of azobenzene dye 2 to mono-amido DAN units 4, 7, and 9 was effected by classic 4-(dimethylamino) pyridine (DMAP)-catalyzed peptide synthesis with N-(3-dimethylaminopropyl)-N'-ethyl carbodiimide hydrochloride (EDC) as activating agent, affording the respective amide products 5, 8, and 10 in 60-71% yield. The amide linkage was formed through either the aliphatic or aromatic ester group of 2, allowing both the flexibility and absorption maximum to be tuned. Azobenzene dye 1 was coupled to the DeUG unit 11 by Steglich esterification to afford the product amide 12 in 35% yield. Alternatively, azobenzene dye 16 underwent a room-temperature copper-catalyzed azide-alkyne Huisgen cycloaddition with DeUG alkyne 17 to give triazole 18 in 71% yield. Azobenzene coupled DAN modules 5, 8, and 10 are bright orange-red in color, and azobenzene coupled DeUG modules 12 and 18 are orange-yellow in color. Azobenzene coupled DAN and DeUG modules were successfully used as colorimetric indicators for specific DAN-DeUG and DAN-UPy (2-ureido-4(1H)-pyrimidone) quadruply hydrogen-bonding interactions.

• 出版日期2012-4-2