lead is quantitatively retained on 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-br-padap)-ammonium tetraphenylborate with microcrystalline naphthalene or by a column method in the ph range 4.0-6.0 from a large volume of aqueous solutions of various samples with preconcentration factor of 60. after filtration, the solid mass consisting of the lead complex and naphthalene was dissolved with 5...

brønsted acidic ionic liquid triethylamine-bonded sulfonic acid {[et3n-so3h]cl} efficiently catalyzes the one-pot multi-component condensation of 2-naphthol with arylaldehydes and dimedone (5,5-dimethylcyclohexane-1,3-dione) under solvent-free conditions to afford 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthen-11-ones in high yields and relatively short reaction times.

in this work, modification of carbon paste electrode surface with poly (2, 5-dimethyl aniline) (p-2,5-dma) by using electrochemical polymerization was described. then, transition metal ions of ni(ii) were incorporated into the polymer film by two ways. at first way, the polymeric modified electrode was immersed in 0.2 m niso4 solutions and the second way was carried out by electrodeposition of ...

melamine trisulfonic acid (mtsa) as an efficient heterogeneous catalyst has been used for the one-pot preparation of triazolo[1,2-a]indazole-1,3,8-trione and 2h-indazolo[2,1-b]phthalazine-1,6,11-trione derivatives by the three-component condensation reaction of urazoles or phthalhydrazide, dimedone or 1,3-cyclohexanedione, and aldehydes under solvent-free conditions in good to excellent yields ...

electrochemical oxidation of iodide has been studied in the presence of 2-thioborbituric acid using cyclic voltammetry and controlled-potential coulometry. the results indicate that, the resulting iodine takes part in halogenations reaction with 2-thiobarbituric acid. in addition, the present data are indicative of the suitability of iodide as a quasi mediator for determination of 2-thiobarbitu...

catalytic osmylation of cis and trans 2-cyclohexene-cyclohexanol (1a) and (1b) are carried out in the presence of n-methyl morpholine-n-oxide. under the same conditions, only the cis isomer reacted, leading to triol (3). the steric hindrance of the equatorial oh group probably prevents the trans isomer from entering into such reaction. triol (3) was also obtained from the reduction of the diol-...

the one-pot, multi-component synthesis of 4,4′-(arylmethylene)bis(1h-pyrazol-5-ols) by tandem knoevenagel-michael reaction of phenylhydrazine, ethyl acetoacetate and aldehydes in the presence of silica-bonded n-propylpiperazine sulfamic acid (sbppsa) as a recyclable solid acid catalyst was reported. sbppsa showed much the same efficiency when used in consecutive reaction runs.

1-carboxymethyl-3-methylimidazolium chloride {[cmmim]cl} is utilized as a highly efficient and reusable catalyst for the synthesis of bis(indolyl)methanes by the condensation reaction of indole with arylaldehydes under solvent-free conditions at room temperature. in summary, the presented method have several advantages including simplicity, low cost, generality, efficiency, clean reaction profi...

this paper describes the applicability of 1,3-dichloro-5,5-dimethylhydantoin, as a cheap, stable and commercially available catalyst, in the promotion of the synthesis of 1,8-dioxo-octahydro-xanthenes (doxos) via the one-pot condensation of aldehydes and cyclic 1,3-dicarbonyl compounds. this novel synthetic method has the advantages of high yields, short reaction times, low cost and availabilit...