A practical and green method for the synthesis of 5H-dibenzo[b,i]xanthene-tetraones and spiro[dibenzo[b,i]xanthene-13,3'-indoline]-pentaones by the condensation of 2-hydroxynaphthalene-1,4-dione with aldehydes or isatins, respectively, in the presence of a catalytic amount of cellulose sulfuric acid (CSA) under solvent-free conditions at 100 °C is described. The significant features of this pro...

Fe3O4 magnetic nanoparticles were synthesized by co-precipitation of Fe2+ and Fe3+ in aqueous NaOH. Then silica was coated on the obtained nanoparticles and the whole composite was functionalized with chlorosulfonic acid in CH2Cl2. The obtained nanocomposite (Fe3O4@SiO2-SO3H) was characterized by FT-IR, VSM and XRD techniques and was used as an efficient catalyst in condensation reaction of ind...

(1) If heated with iodine as a catalyst, the tertiary alcohol (I) readily yielded the olefin (III). (2) This olefin rearranged immediately to the dicyclic hydrocarbon (II) when digested with concentrated sulfuric acid. (3) Treated with the proper concentration of sulfuric acid, or phosphoric acid, the alcohol (I) passed immediately to the olefin (III), which on longer treatment changed to the i...

Treatment of deactivated aromatic compounds with Nbromosuccinimide in trifluoroacetic acid solvent in the presence of sulfuric acid gave the corresponding monobromoaromatic compounds in good to excellent yields.

The distribution of charged species produced by electrospray of an ammonium sulfate solution in both positive and negative polarities is examined using Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS). Positively-charged ammonium bisulfate cluster composition differs significantly from negatively-charged cluster composition. For positively-charged clusters all sulfuric acid...

The classical procedure for the preparation of homocystine consists of boiling a solution of methionine in 50 per cent sulfuric acid followed by neutralization (1). Although the yields of homocystine account for only 25 to 45 per cent of the methionine, the nature of the reaction has received little attention since originally published by Butz and du Vigneaud (1). These authors noted the format...

This study examines endogenous acid production in a group of stable chronic hemodialysis patients with no residual renal function who were admitted to the chronic hemodialysis unit of Mount Sinai Hospital. Net acid production was estimated by the change in body bicarbonate content, which occurs in the interdialytic period. The body bicarbonate content at any time was measured by multiplying the...

In this work, a tracer study on pore initiation in anodic alumina in oxalic acid was performed. Effects of some experimental parameters such as applied electrical potential, electrolyte composition and heat pretreatment were evaluated. Electrochemical and morphological experiments were performed using potentiostatic anodizing and scanning electron microscopy (SEM) techniques, respectively. Effe...