Premium
Synthesis and fluorescence properties of substituted 7‐aminocoumarin‐3‐carboxylate derivatives
Author(s) -
Corrie John E. T.,
Munasinghe V. Ranjit N.,
Rettig Wolfgang
Publication year - 2000
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570370608
Subject(s) - chemistry , trifluoromethyl , fluorescence , substituent , carboxylate , intramolecular force , carboxamide , halogenation , maleimide , reagent , stokes shift , hydrolysis , photochemistry , stereochemistry , medicinal chemistry , organic chemistry , alkyl , physics , quantum mechanics
Abstract 4‐Trifluoromethyl‐ or 6‐bromo‐substituted 7‐diethylaminocoumarin‐3‐carboxamide derivatives 2 and 3, each containing a maleimide have been synthesized as potential fluorescent labeling reagents for thiol groups in proteins and their fluorescence properties have been determined. The 4‐trifluoromethyl substituted compound 2 has a significantly greater Stokes shift than the comparable compound lacking this group, but both the new coumarins have low fluorescence quantum yields (ϕ f ). When a 4‐trifluoromethyl substituent is present, the 3‐carboxamide is unusually labile to hydrolysis. Bromination of ethyl 7‐diethylaminocoumarin‐3‐carboxylate 17 gave the 6‐ and 8‐bromo derivatives 18 and 19 respectively, and also the 8‐bromo‐7‐monoethylamino compound 20. ϕ f for the latter compound is 100‐fold greater than for its diethylamino analogue 19. Fluorescence lifetime measurements support an interpretation based on the twisted intramolecular charge transfer (TICT) model to explain these large differences in ϕ f .