Syntheses of fluorescent dyes. IX. New 4‐hydroxycoumarins, 4‐hydroxy‐2‐quinolones, 2H,5H‐Pyrano[3,2‐c]benzopyran‐2,5‐diones and 2H,5H‐Pyrano[3,2‐c]quinoline‐2,5‐diones

Abstract

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 2H,5H‐pyrano[3,2‐c]benzopyran‐2,5‐diones (5a‐r) or 2H,5H‐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.

Synthesis, PM3‐Semiempirical, and Biological Evaluation of Pyrazolo[4,3‐c]quinolinones

“…Reactions were monitored by thin‐layer chromatography and preparative thin layer chromatography carried out on 0.2–0.4 mm silica gel 60F254 (Merck) plates using UV light (254 and 366 nm) for detection. 7‐Methoxyquinoline‐2,4‐(1 H ,3 H )‐dione ( 1 ) was prepared according to the previously reported method . Biological testing was carried out at Drug Department, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt.…”

Synthesis and Antimicrobial Evaluation of Novel Polyfused Heterocycles‐Based Quinolone

“…Reactions were monitored by TLC and preparative TLC carried out on 0.2–0.4 mm silica gel 60 F254 (Merck, USA) plates using UV light (254 and 366 nm) for detection. 7‐Methoxyquinoline‐2,4‐(1 H ,3 H )‐dione ( 1 ) was prepared according to the previously reported method . Antimicrobial testing was carried out at the Faculty of Pharmacy, Mansoura University, Mansoura, Egypt.…”

A coumarin derivative covalently immobilized on sensing membrane as a fluorescent carrier for nitrofurazone

“…To date, this category of compounds have rarely been used as fluorescent carriers for optical chemosensing. To investigate the fluorescence properties of coumarin derivatives, Knierzinger et al [16] synthesized 2H, 5H-pyrano[3, 2-C] benzpyran 2, 5-diones that were modified by Cheng et al [17] to obtain 4-methyl-8-amino-2H, 5H-pyrano[3, 2-C] benzpyran 2,5-diones (MAPBD). In this compound, an amino group in the 8-position as an electron-donating group can enhance the charge transfer ability in the molecule, and the lowering of charge density around the double bond (3,4-position) is beneficial to the polarization of molecule.…”