The Use of Umbelliferone in the Synthesis of New Heterocyclic Compounds

Abstract

New coumarin derivatives, namely 7-[(5-amino-1,3,4-thiadiazol-2-yl)methoxy]-2H-chromen-2-one (4), 5-[(2-oxo-2H-chromen-7-yloxy)methyl]-1,3,4-thiadiazol-2(3H)-one (5), 2-[2-(2-oxo-2H-chromen-7-yloxy)acetyl]-N-phenylhydrazinecarbothioamide (7), 7-[(5-(phenylamino)-1,3,4-thiadiazol-2-yl)methoxy]-2H-chromen-2-one (8) and 7-[(5-mercapto-4-phenyl-4H-1,2,4-triazol-3-yl)methoxy]-2H-chromen-2-one (9) were prepared starting from the natural compound umbelliferone (1). The newly synthesized compounds were characterized by elemental analysis and spectral studies (IR, 1H-NMR and 13C-NMR).

Photostabilizing Efficiency of PVC in the Presence of Schiff Bases as Photostabilizers

“…However, the working principles of this approach are not yet fully understood [15]. In the continuation of previous studies [16][17][18][19][20][21][22][23], we focused on the photostabilization of PVC using 1,3,4-thiadiazole compounds. To our knowledge, there has been no attempt to investigate the photostabilization of PVC films by Schiff bases containing four 1,3,4-thiadiazole rings; therefore, in this study, we report the design of the Schiff bases and the study of their use as a photostabilizing reagents.…”

Theoretical Studies on Electrophilic Aromatic Substitution Reaction for 8-Hydroxyquinoline

“…The B3LYP density functional theory calculations exhibit good performance on the molecular geometry and vibrational properties of organic compounds 8,9 . To extend our studies on the design and synthesis of new compounds [10][11][12][13][14][15][16][17][18][19][20][21][22] , we describe here, investigate the dependence of stability of the molecules on theoretical chemical parameters such as total energy, energy level of (HOMO), and energy gap. We have three stable molecules, HQ-7-YBAEE (II) for the total energy, HQ-6-YBAEE (II) for the energy level of (HOMO) and HQ-2-YBAEE (II) for the energy gap.…”

Solvent-Free Synthesis of New Coumarins

“…Recently, density functional theory (DFT) has been accepted by the quantum chemistry community as a cost-effective approach for the computation of molecular structure, vibration frequencies, and energies of chemical reactions. Many studies have shown that the molecular structures and vibration frequencies calculated by DFT methods are more reliable than MP2 methods [18][19][20][21][22][23][24][25][26]. While there is sufficient evidence that DFT provides accurate description of the electronic and structural properties of solids, interfaces, and small molecules, relatively little is known about the symmetric performance of DFT applications to their molecular associates.…”