The reaction of 3-chloropropyl boehmite nanoparticles with caffeine and sulfuric acid afforded BNPs-3-propyl-imidazolopyridinium hydrogen sulfate [BNPs-Caff]HSO4 as a new BNPs-supported ionic liquid (IL) catalyst. [BNPs-Caff]HSO4 proved to be an efficient heterogeneous catalyst for the synthesis of pyrazolopyranopyrimidines via a one-pot four-component reaction of...

[1] The characteristics and sources of what are believed to be newly formed 3 to 4 nm particles in anthropogenic plumes advecting from Asian are reported. Airborne measurements were made from March to April 2001 as part of the NASA TRACE-P experiment at latitudes ranging from North of the Philippines to Northern Japan (20 to 45 N). In the more polluted plumes, high concentrations of 3 to 4 nm d...

the aryl-(z)-n-[2-amino-1,2-dicyanovinyl]formamidine 2 cyclize in solvent-free conditions and in the presence of a base to give a 5-amino-1-aryl-4-cyanoimidazoles 3. silica sulfuric acid as an efficient and reusable heterogeneous catalyst has been used for the preparation of amidines 2 from formimidate 1 through reaction with aromatic amines at room temperature and in good to excellent yields. ...

A definitive method is described for the indirect assay of several tens of milligrams of urea by coulometric titration. Urea was decomposed in concentrated sulfuric acid using a Kjeldahl flask. Subsequently, the formed ammonium ion was titrated with electrogenerated hypobromite ion in a sodium bromide-sodium tetraborate medium of pH 8.6, with amperometric end-point detection. Parameters affecti...

A gas phase chemiluminescence (GPCL)-based method for trace measurement of arsenic has been recently described for the measurement of arsenic in water. The principle is based on the reduction of inorganic As to AsH(3) at a controlled pH (the choice of pH governs whether only As(III) or all inorganic As is converted) and the reaction of AsH(3) with O(3) to produce chemiluminescence (Idowu et al....