Fluorescence emission after two-photon absorption of coumarins and xanthenes in an alcoholic solution was measured in the tuning range of a femtosecond-pulsed titanium-sapphire laser (750-840 nm). Xanthenes, which have a low one-photon absorption in the near UV, show a higher fluorescence signal after two-photon absorption than the UV-excitable coumarins. When fluxes of 10(28) photons/(cm(2) s)...

Coumarins are classified as a member of the benzopyrone family. all of which consist of a benzene ring joined to a pyrone ring. The benzopyrones can be subdivided into the benzoalfa-pyrones to which the coumarins belong and the benzo-gama-pyrones, of which the flavonoids are principal members. Umbelliferone, esculetin and scopoletin are the most widespread coumarins in nature. During the synthe...

Pd-catalyzed oxidative Heck reactions of coumarins were developed via simultaneous C-H functionalization at the C3 position of coumarins under aerobic conditions.

The Coumarine heterocyclic ring is common feature of various bioactive compounds such as calanolides, lipid-lowering agents. The Chemists all over the globe are motivated not only for the environmentally benign synthesis of new products but also to develop green synthesis for existing chemicals. Coumarins, the most important classes of fluorescent molecules constitute important structural featu...

1. Abstract 2. Introduction 3. Phytoalexins and cancer prevention mechanisms 3.1. Antimicrobial activity 3.2. Proliferation 3.2.1. Cruciferous phytoalexins 3.2.2. Deoxyanthocyanidins 3.2.3. Glycoalkaloids 3.2.4. Stilbenes 3.2.5. Phenolic coumarins and garlic phytoalexins 3.3. Apoptosis 3.3.1. Stilbenes 3.3.2. Phenolic coumarins 3.3.3. Glycoalkaloids 3.3.4. Garlic phytoalexins 3.3.5. Di-terpenes...

Herein, we report a convenient one-pot synthesis of 1,2,4-triazinyl derivatives benzocoumarins. The proposed approach consists in the nucleophilic addition tetrahydrobenzo annulated dimethoxycoumarin to 1,2,4-triazines followed by double oxidation both dihydrotriazine and groups with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). was carried out presence three-fold excess methanesulfonic acid...

Coumarins are one of the most important classes of heterocycles that occupies prime position in synthetic and pharmaceutical chemistry due to their diverse applications. Broad spectrum of biological activity and their utility as useful synthons, coumarins have attracted researchers to work on this moiety, which is instrumental in the development of coumarin chemistry. This review article provid...