A new type of ratiometric fluorescent probe, 8-(diethylamino)-2-methyl-4-oxo-4H-pyrano[2,3-b] chromen-10-ylium tetrafluoroborate (APCT), is reported. A new type of ratiometric fluorescent probe, 8(diethylamino)-2-methyl-4-oxo-4H-pyrano[2,3-b]chromen-10-ylium tetrafluoroborate (APCT), is reported. This probe can successfully detect bisulfite anions with a detection limit of 6.1 10 7 M based on M...

The chloroform solvate of uncarine C (pteropodine), (1'S,3R,4'aS,5'aS,10'aS)-1,2,5',5'a,7',8',10',10'a-octahydro-1'-methyl-2-oxospiro[3H-indole-3,6'(4'aH)-[1H]pyrano[3,4-f]indolizine]-4'-carboxylic acid methyl ester, C(21)H(24)N(2)O(4).CHCl(3), has an absolute configuration with the spiro C atom in the R configuration. Its epimer at the spiro C atom, uncarine E (isopteropodine), (1'S,3S,4'aS,5'...

pyrano [2,3-d] pyrimidinone derivatives have received considerable interest from the pharmaceutical industry due to their wide range of interesting biological and therapeutic properties. nano al2o3 was found to be a highly efficient solid acid catalyst for the preparation of pyrano [2,3-d] pyrimidinone derivatives from the reaction of barbituric acid, aryl aldehyde and malononitrile. al2o3 nano...

Fusion of a pyrone ring with a benzene nucleus gives rise to a class of heterocyclic compounds called Benzopyrones, of which two distinct types are recognized: (1) benzo-α-pyrone commomly called coumarins and (2) benzo-Υ-pyrone called chromones or flavanoids, latter differing from former only in the position of the carbonyl group in heterocyclic system. Coumarins have attracted considerable att...

A highly practical and efficient preparation of pyrano[3,2-c]pyridone and pyrano[3,2-c]quinoline derivatives was developed via an ionic liquid mediated and promoted multi-component reaction of malononitrile, aldehyde, and 4-hydroxyquinolin-2(1H)-one or 4-hydroxy-6-methylpyridin-2(1H)-one. The combinatorial syntheses were achieved for the first time without applying extra activation energy at am...

A new pyranoxanthone namely 5,9,11-trihydroxy-2,2-dimethyl-3-(2-methylbut-3-en-2-yl) pyrano[2,3-a]xanthen-12(2H)-one (1) was isolated from the stem bark of Calophyllum tetrapterum Miq. The structure of compound 1 was determined by means of spectroscopic methods including UV, IR, HRESIMS, 1D and 2D NMR.

ABSTRACT Knoevenagel condensation of barbituric acids with aromatic aldehydes containing one or two formyl groups was carried out. 5-Arylidenebarbituric acids underwent smooth hetero-Diels-Alder (HDA) reactions with enol ethers to afford cis and trans diastereoisomers of pyrano[2,3-d]pyrimidine-2,4-diones and 5,5'-(1,4-phenylene)bis[2H-pyrano[2,3-d]pyrimidine-2,4(3H)-dione] derivatives in excel...

BACKGROUND The benefit and risk of oral anticoagulation in dialysis patients are debated controversially. METHODS We prospectively followed 235 dialysis patients of the INVOR Study (Study of Incident Dialysis Patients in Vorarlberg) for up to 7 years and analysed the prevalence and incidence of atrial fibrillation (AF) and the impact of coumarin therapy on survival. Oral anticoagulation was m...

There has been special interest in the chemistry of quinolone and pyrimidine derivatives due to their diverse biological activities such as anticonvulsant, anti-malarial agents, antibacterial, antiviral, cytostatic, antithelemintic, antigenotoxic, anti-cancer agents. These compounds are also used as targeting delayed-type hypersensivity and anti-convulsant agents. As a part of our research work...