Adsorption characteristics and separation of Cr(III) and Cr(VI) on hydrous titanium(IV) oxide.

A hydrous titanium(IV) oxide was prepared to study the adsorption characteristics and the separation of chromium species. Batch sorption studies have been carried out to determine the effect of pH on the sorption of Cr(III) and Cr(VI) on hydrous TiO2. An excellent separation efficiency of Cr(III) and Cr(VI) was obtained at pH 2. The adsorption percentage of Cr(VI) was above 99%, whereas that of the Cr(III) was less than 1% at this pH. The adsorption isotherm of Cr(VI) on hydrous TiO2 at pH 2 was in good agreement with the Langmuir isotherm. The maximum adsorption capacity of Cr(VI) on TiO2 was 5 mg g(-1). The rate of adsorption of Cr(VI) by hydrous TiO2 with average particle diameter 250 and 500 microm has been studied under particle diffusion controlled conditions. The diffusion coefficients of Cr(VI) for both hydrous TiO2 having average particle diameter of 250 and 500 microm was calculated at pH 2 as 3.84 x 10(-10) m2 s(-1) and 8.86 x 10(-10) m2 s(-1), respectively.

Total synthesis of SR 121463 A, a highly potent and selective vasopressin v(2) receptor antagonist.

SR 121463 A, 1, is a promising nonpeptide prototype for potent and selective antagonism of the vasopressin V(2) receptor subtype and, thus, a candidate for control of the clinically debilitating condition of hyponatremia and its associated syndromes. In the present work, we present a novel and stereoselective synthesis that stems from the preparation of three key intermediates: the substituted benzenesulfonyl chloride 2, the N-protected oxindole 3, and protected dibromide 4. The synthesis of 1 has been achieved in good overall yield, each step proceeding in greater than 80% yield. In addition, intermediate 2 and the syn isomer of 1 were prepared with complete control of stereochemistry. The latter reduction appears to proceed by lithium cation mediated chelation control. Molecular mechanics calculations with the MM3* and MMFF force fields underscore geometric and energetic aspects of the reaction.

Studies on calcium modulatory activities of 2,6,6-trimethyl-3-acetyl-4-aryl-5-oxo-1,4,5,6,7,8-hexahydroquinoline derivatives.

Twenty-two new 2,6,6-trimethyl-3-acetyl-4-aryl-5-oxo-1,4,5,6,7,8-hexahydroquinoline+ ++ derivatives (compounds 1-22) have been prepared. The structures of the compounds were characterised by IR, 1H-NMR, mass spectroscopy and elemental analyses. The calcium antagonistic activities of the compounds were determined by the tests performed on isolated rabbit ileum and lamb carotid artery. According to the isolated rabbit ileum activity tests the most active compounds are 10 and 12 and according to the lamb carotid activity tests the most active compounds are 6 and 10.

2-methyl-3-acetyl-4-aryl-5-oxo-1,4-dihydro-5H indeno(1,2-b) pyridine derivatives studies and their calcium antagonistic activities.

Sixteen 2-methyl-3-acetyl-4-aryl-5-oxo-1,4-dihydro-5H-indeno(1,2-b)pyridine derivatives (3a-p) have been prepared. The structures of the compounds were characterised by IR, 1H-NMR, 13C-NMR, X-Ray and elemental analyses. The calcium antagonistic activity of these compounds were studied in rat taenia coli pre-contracted with 1 mmol/l Ca+2.

One pot synthesis of some new substituted hexahydro 2H-1,3-benzoxazine derivatives.

In this paper, we synthesized nineteen new compounds having 2,4-diaryl-5-oxohexahydro-2H-1,3-benzoxazine structure by the reaction of 1,3-cyclohexanedione, aromatic aldehyde and ammonium acetate. In addition, we evaluated calcium antagonistic activity of these compounds versus nicardipine.

Synthesis and antimicrobial activity of some 2-(2-oxobenzothiazole-3-yl)-1-arylethanone derivatives.

The synthesis of new 2-(2-oxobenzothiazole-3-yl)-1-arylethanone derivatives is reported. The structure of these products is supported by their UV, IR and 1H-NMR spectra, as well as by elemental analysis. The new compounds were tested for antimicrobial activity.