7-Aminocoumarins (Review)

Bright Ideas for Chemical Biology

“…Different reactive groups are compatible with this fluorophore, and are typically attached at the 3 or 4 position of coumarin (13). The spectral characteristics of AMC can be tuned through different nitrogen substitution patterns (65). Still other substitutions (e.g., fluoronation or sulfonation) can yield coumarin dyes with desirable chemical properties, such as higher solubility in aqueous solution and lower sensitivity to pH (64,66).…”

Quadrupolar Dyes Based on Highly Polarized Coumarins

“… 7 , 8 It is well-known that 7-aminocoumarins exhibit excellent emissive properties. 9 Intriguingly, switching the position of an electron-donating substituent from 7 to 6 leads to marked differences in optoelectronic properties. 10 − 14 In the case of 6-aminocoumarins the emission is weak and red-shifted in comparison with the corresponding 7-aminocoumarins.…”

“…Since then, interest in this class of substances has remained strong owing to the many derivatives that display broad biological activity. , Coumarins have also attracted significant scientific attention due to their unique photophysical properties. − Their simple synthesis combined with the relative ease of functionalization makes it possible to create a wide range of dyes . A particularly important class of coumarin-based emitters are donor–acceptor systems possessing an electron-donating substituent at position 7 and an electron-withdrawing one at position 3. , It is well-known that 7-aminocoumarins exhibit excellent emissive properties . Intriguingly, switching the position of an electron-donating substituent from 7 to 6 leads to marked differences in optoelectronic properties. − In the case of 6-aminocoumarins the emission is weak and red-shifted in comparison with the corresponding 7-aminocoumarins. , In this letter we address a key question: is this a general effect of electron-donating substituents irrespective of their structure?…”

Fluorescent Dyes with Large Stokes Shifts of 80−200 nm for Optical Microscopy and Nanoscopy

“…Methods of their synthesis and their photophysical properties were reviewed. [33] The parent compound 7-aminocoumarin has the main band at 380 nm (ε = 18000 M −1 cm −1 ) in water and the emission maximum at 444 nm (Φ fl = 0.55 [34] , Stokes shift of 64 nm). Amino groups, in particular if they are not or only partially alkylated are capable of forming hydrogen bonds with molecules of water.…”

“…However, under prolonged action of a base, the cis-coumarinate isomerizes to the trans-isomer which cannot cyclize back to the starting coumarin upon acidification. [33] Both tert-butyl groups in compound 306 were easily removed upon treatment with trifluoroacetic acid, and the target dye 308 was isolated in an excellent yield.…”