A Pseudomonas sp. isolated from sewage by enrichment culture on quinoline metabolized this substrate by a novel pathway involving 8-hydroxycoumarin. During early growth of the organism on quinoline, 2-hydroxyquinoline accumulated as the intermediate; 8-hydroxycoumarin accumulated as the major metabolite on further incubation. 2,8-Dihydroxyquinoline and 2,3-dihydroxyphenylpropionic acid were ide...

Coumarin derivatives possessing diverse biological activities play important roles as versatile building blocks for the synthesis of natural products and biologically active compounds. In particular, 4-hydroxycoumarin derivatives, such as 4-hydroxycoumarin and 4-hydroxythiocoumarin, have been used as useful intermediates for the synthesis of anticoagulants, herbicides, and anticancer agents. Re...

a novel catalytic synthesis of 3,3'-(arylmethylene)-bis-(4-hydroxy-2h-chromene-2-one) derivatives from a tandem condensation reaction of 4-hydroxycoumarin and aromatic aldehydes has been developed. the reaction occurs in water in the presence of melamine trisulfonic acid as catalyst to give the corresponding products in good to high yields. this green approach has several advantages such as sho...

A series of 1,3,5-triazine derivatives that contain aniline, 4-hydroxycoumarin and 7-hydroxy-4-methylcoumarin and different piperazines and piperidines as substituents on the carbon atoms of the triazine ring has been synthesized by a simple and efficient synthetic protocol. Comparative studies were performed on above compounds, which were synthesized with conventional and microwave heating met...

Activity-guided fractionation of twigs of Pistacia chinensis resulted in the isolation and characterization of two novel ingredients as potent estrogen agonists. On the basis of spectral analysis and comparison with a related compound their structures were elucidated as 3,3''-dimers of 4-aryldihydrocoumarins (3,4-dihydro-4-(4'-hydroxyphenyl)-7-hydroxycoumarin) differing only in the stereochemic...

The status of hepatic function can be altered by diverse influences. Multiple functional processes are measurably affected by several extrinsic toxic agents (typhoid toxin, chloroform, yellow phosphorus) as well as by a large number of pathological disorders. After exposure to toxins, in obstructive jaundice, in cirrhotic processes, in intrahepatic tumors and the like, either anatomical disrupt...

The fluorescent unnatural amino acid, (7-hydroxycoumarin-4-yl)ethylglycine (HC), was site-specifically incorporated at the Phe69 site, close to the entrance of the selectivity filter of the NaK channel. Decreased fluorescence lifetime and elevated time-resolved anisotropy of NaK-F69HC in buffers with high K(+)/Na(+) molar ratios indicated the K(+) preference at the entrance of the NaK channel, ...