Coumarins have much importance in dyes, drugs, perfumes and pesticides. In the demonstrated research work, a benignant series of chlorinated coumarins was synthesized and screened against different enzymes. First, 6-Chloro-7-hydroxy-4-methyl-2H-chromen-2-one (3) was geared up by the reaction of 4-chlororesorcinol (1) and ethyl acetoacetate (2) in the presence of concentrated H(2)SO(4). Second, ...

The structure of 7,8-dihydroxy-4-methylcoumarin was determined by an X-ray diffraction method. The compound crystallized in the triclinic space group P1, Z = 2, with a = 7.631(2), b = 9.456(5), c = 7.075(3)A, alpha = 103.13(3), beta = 91.84(3), gamma= 68.21(3) degrees, and V= 460.9(3)A3. The X-ray crystal structure was also compared with those of 5,7-dihydroxy-4-methylcoumarin and 7-hydroxy-4-m...

A new geranylated coumarin, (E)-4-(1-hydroxypropyl)-5,7-dihydroxy-6-(3,7-dimethyl-2,6-octadienyl)-8-(3-methyl-1-oxobutyl)coumarin (named surangin D), was isolated from the bark of Mammea siamensis collected in Vietnam, along with four known coumarins, surangins B and C, and theraphins B and C, and seven xanthones, 1,7-dihydroxyxanthone, 7-hydroxy-1-methoxyxanthone, 1,7-dimethoxyxanthone, 1,7-di...

Absorption and fluorescence spectra of bichromophoric coumarins were investigated in different solvents and in polymer matrices. These bichromophoric coumarins were composed of a coumarin dimethylamino-substituted at position 7 or unsubstituted coumarin and phthalimide or a 1,8-naphthylimide linked with an iminomethyl bridge to the position 3 or 8 of the coumarin ring. Absorption spectra of 7-d...

BACKGROUND Glycosmis is a genus of evergreen glabrous shrub and distributed all over India. It possesses various medicinal properties and is used in indigenous medicine for cough, rheumatism, anemia, and jaundice. Glycosmis arborea is a rich source of alkaloids, terpenoids, coumarins, as well as flavonoids. RESULTS The chemical investigation of methanol fraction of the leaves of G. arborea le...

Excited states of two 7-aminocoumarin derivatives, coumarin 120 (7-amino-4-methylcoumarin) and coumarin 151 (7-amino-4-trifluoromethylcoumarin), were investigated using generalized multiconfigurational quasidegenerate perturbation theory (GMC-QDPT), multiconfigurational quasidegenerate perturbation theory (MC-QDPT) and time-dependent density functional theory (TDDFT) with the B3LYP and CAM-B3LY...

The absorption and fluorescence spectra of substituted coumarins (2-oxo-2H-chromenes) were investigated in solvents and in polymer matrices. The substitutions involved were: (1) by groups with varying electron donating ability such as CH₃, OCH₃ and N(CH₃)₂, mainly, but not exclusively, in positions 7 and (2), by either CHO or 4-PhNHCONHN=CH- in position 3. While the spectra of non-substituted c...

A base-free process to access indole-fused polyheterocycles via a highly efficient and atom-economic palladium-catalyzed intramolecular cross dehydrogenetive coupling (CDC) reaction of 4-aniline substituted coumarins, quinolinones, and pyrones has been developed. A wide range of indolo[3,2-c]coumarins, indolo[3,2-c]quinolinones, and indolo[3,2-c]pyrones can be facilely afforded in good to excel...

Large Stokes-shift coumarin dyes with an O-phosphorylated 4-(hydroxymethyl)-2,2-dimethyl-1,2,3,4-tetrahydroquinoline fragment emitting in the blue, green, and red regions of the visible spectrum were synthesized. For this purpose, N-substituted and O-protected 1,2-dihydro-7-hydroxy-2,2,4-trimethylquinoline was oxidized with SeO2 to the corresponding α,β-unsaturated aldehyde and then reduced wit...