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Syntheses of fluorescent dyes. IX. New 4‐hydroxycoumarins, 4‐hydroxy‐2‐quinolones, 2 H ,5 H ‐Pyrano[3,2‐ c ]benzopyran‐2,5‐diones and 2 H ,5 H ‐Pyrano[3,2‐ c ]quinoline‐2,5‐diones
Author(s) -
Knierzinger Andreas,
Wolfbeis Otto S.
Publication year - 1980
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.5570170204
Subject(s) - chemistry , substituent , aniline , quinoline , fluorescence , benzopyran , phenols , medicinal chemistry , condensation , coumarin , organic chemistry , physics , quantum mechanics , thermodynamics
7‐Substituted 4‐hydroxycoumarins (2a‐e) and 4‐hydroxy‐2‐quinolones (2f‐i) have been synthesized from the appropriate phenols or anilines and were converted to the enamines 3 using triethoxymethane and aniline. Condensation of 3 with nitriles 4a‐h gave substituted 2 H ,5 H ‐pyrano[3,2‐ c ]benzopyran‐2,5‐diones (5a‐r) or 2 H ,5 H ‐pyrano[3,2‐ c ]quinoline‐2,5‐diones (5s‐x) , which exhibit both spontaneous and stimulated fluorescence with maxima between 418 and 549 nm. The marked influence of an electron withdrawing 3‐substituent in 5 is demonstrated by the fluorescence spectra of 7a,b (synthesized from 2d,e and ethyl 3‐oxobutyrate), whose maxima are sharply shifted to the blue as compared with compounds 21‐r.