A number of novel 3-bromo-4-methyl-7-methoxy-8-amino substituted coumarins and 2-substituted 7-bromo-6-methyl-8H-pyrano-benzimidazoles, benzoxazoles and/or benzoxazine-8-ones were synthesized for the purpose of pharmacological evaluation. Some representative compounds showed antitumor activity in vitro on Ehrlich ascites carcinoma in the preliminary testing.

Silica sodium carbonate (SSC) has been used as a valuable silica-supported catalyst for the preparation of a range of known and novel pyrano coumarins via the three-component reactions of aryl aldehydes, active methylene compound (malononitrile or ethyl cyanoacetate), and hydroxycoumarin (5,7-dihydroxy-4-substituted coumarins or 4-hydroxycoumarin). The heterogeneous catalyst showed much the sam...

An improved domino/Knoevenagel-hetero-Diels-Alder reaction of two new aldehyde substrates; 7-olefinoxy-coumarin-8-carbaldehyde and 2-alkensulfanyl-quinoline-3-carbaldehyde, with pyrazolones was studied in ionic liquid triethylammonium acetate (TEAA), affording a series of pyrazolopyran annulated-pyrano-fused coumarins, and thiopyrano-fused quinolones. Besides acting as catalyst, since no additi...

The photophysical characteristics of a group of coumarins with a 3:4-fused ring system (2-substituted-4,5-dioxo-l,2-dihydro-4H,5H-pyrano-[3:4-c] [l]-benzopyrans) in solutions at room temperature, in frozen ethanol matrix at 77 K, in solid phase and in PVC films are reported. The low fluorescence quantum yield of the compounds investigated in solution is explained as a result of internal convers...

Several novel naphtho[2,1-b]pyrano[2,3-d]pyrimidines, pyrano[3,2-e][1,2,4]triazolo[1,5-c]pyrimidines and their coumarin-3-yl derivatives were synthesized. Some of these derivatives exhibited pronounced antimicrobial activities.

Starting from commercially available educts, a straightforward synthetic route to new heterocyclic building blocks is exemplified with the one- or two-step synthesis of tri-, tetra-, or pentacyclic ring systems. Representatives of the following novel ring systems are prepared from 3-methyl-1-phenyl-2-pyrazolin-5-one and the corresponding o-halo-arenecarbonyl chloride using calcium hydroxide in ...

The title compound, C(19)H(15)NO(2)S(3), is the first example of a dithia analogue of pyrano[3,4-b]indolone. The almost planar thio-pyrano-indole-thione ring system (r.m.s. deviation for all non-H atoms = 0.030 Å) makes a dihedral angle of 80.70 (8)° with the p-tolyl ring. In the crystal, mol-ecules are connected via C-H⋯O hydrogen bonds into two chains along the b axis. These chains are connec...

A new method for the synthesis of pyran fused coumarins by 3-bromo-4-hydroxycoumarins as cyclic α-halo ketones based on an organocatalyst assisted three-component tandem reaction is investigated. To the best of our knowledge, cyclic α-halo ketones have not yet been used for the synthesis of pyran fused coumarins.

Coumarin derivatives are an important class of C6-C3 plant metabolites that show a variety of bioactivities. Currently, most clinical anticoagulant agents are coumarins, such as warfarin, dicoumarol and acenocoumarol, and patients taking these drugs must be monitored for adverse reactions. In a search for safe and effective anticoagulant compounds from Chinese herbal medicine, a screening proce...