The further development of derivatizing reagents for plasma amino acid quantification by tandem mass spectrometry is described. The succinimide ester of 4-methylpiperazineacetic acid (MPAS), the iTRAQ reagent, was systematically modified to improve tandem mass spectrometer (MS/MS) product ion in...

Development of a solvent extraction process with a single solvent for separating Co and No has the advantages of succinct process and recyclability of components. Main problem with the known specific organic extractants are they are expensive and have limited availability. Previous research on C...

The state of d and l-dimethyl tartrate confined within dry sodium bis(2-ethylhexyl) sulfosuccinate (AOT) reverse micelles dispersed in CCl4 has been investigated by FT-IR spectroscopy, polarimetry, and vibrational circular dichroism (VCD). Measurements have been performed at 25 °C as a function...

This article describes the synthesis and characterization of the 1-ethyl-7-methyl-4-oxo-1,4-dihydro-1,8-naphthyridine-3-carbohydrazide (hzd) and six carbonyl hydrazones derivatives of the nalidixic with 1H-pyrrol-2-ylmethylidene (hpyrr), 1H-imidazol-2-ylmethylidene (h2imi), pyridin-2-ylmethylide...

An improved method for the synthesis of 3α,7α-dihydroxy-5β-chol estan-26-oic acid and 3α, 7α, 12α-trihydroxy-5β-cholestan-26-oic acid is described. The method involves an Arndt-Eistert rearrangement of the corresponding diazoketone obtained by the action of diazoethane on 3α, 7α-diformy...

Background & Aims: Inborn errors of bile acid metabolism may present as neonatal cholestasis and fat-soluble vitamin malabsorption or as late onset chronic liver disease. Our aim was to fully characterize a defect in bile acid synthesis in a 2-week-old African-American girl presenting with coagu...

A new method for the preparation of 5β-cholestan-26-oic acids 7 and their analogs is described. The key steps in the synthesis are: iodination of bis- and tris-formyloxy-5β-cholan-24-ols 3; nucleophilic substitution of iodides 4 with diethyl sodiomalonate; complete alkaline hydrolysis of ester...

Four stereoisomers of 3α,7α,12α,24-tetrahydroxy-5β-cholestan-26-oic acids were synthesized as possible intermediates of the side-chain degradation step of bile acid biosynthesis. 3α,7α,12α-Trihydroxy-5β-cholest-25-en-24-one prepared by thermolysis of β-ketosulfoxide was reduced to the (...

Bile alcohols and bile acids from gallbladder bile of the Arapaima gigas, a large South American freshwater fish, were isolated by reversed-phase high-performance liquid chromatography. The structures of the major isolated compounds were determined by electrospray-tandem mass spectrometry and nu...

[7β-3H]-(24R and 24S)-27-nor-24-methyl-3α,7α-dihydroxy-5β-cholestan-26-oic acids and [7β-3H]-27-nor-3α,7α-dihydroxy-5β-cholestan-26-oic acid (C27 and C26 bile acids having the same nuclear configuration as cheno-deoxycholic acid and its precursor, 3α,7α-dihydroxy-5β-cholestan-26-oic-a...

The biosynthetic intermediates of bile acid, 3α,7α,12α-trihydroxy- and 3α,7α-dihydroxy-5β-cholestan-26-oic acids, were synthesized by means of the thermal elimination of β-ketosulfoxides. The α, β-unsaturated ketones as key compounds of the synthesis, 3α,7α,12α-trihydroxy- and 3α,7α...

Synthesis of 25R- and 25S-diastereoisomers of 3α,7α-dihydroxy-5β-cholestan-26-oic acid from 3α,7α,12α-trihydroxy-5β-cholestan-26-oic acid is described. The 25S-diastereoisomer of 3α,7α, 12α-trihydroxy-5β-cholestan-26-oic acid was obtained by vigorous hydrolysis of the bile of Alligato...

3α,7α,12α-Trihydroxy- and 3α,7α-dihydroxy-24-oxo-5β-cholestan-26-oyl CoAs were chemically synthesized by the conventional method for the study of side chain cleavage in bile acid biosynthesis. 3α,7α,12α-Triformyloxy- and 3α,7α-diformyloxy-5β-cholan-24-als were initially subjected to ...

An efficient synthesis of a library of 5-amino-thiazolo[4,5-d]pyrimidines is reported. Regioselective displacements of chlorines, as well as regioselective diazotation reactions are described, which allow the introduction of structural diversity on the scaffold by consecutive reactions. Screenin...

A new series of 5-methyl-thiazolo[5,4-d]pyrimidine-7-ones bearing different substituents at position 2 (aryl, heteroaryl and arylamino groups) was synthesized and evaluated in radioligand binding assays to determine their affinities at the human (h) A1, A2A, and A3 adenosine receptors (ARs). Eff...

Thiazolo[5,4-d]pyrimidines are important class of heterocyclic compounds possessing diverse range of biological activities. Herein, we report an efficient synthesis of thiazolo[5,4-d]pyrimidines using recyclable KF/alumina catalyst. The reaction of 4,6-dichloro-5-aminopyrimidine with isothiocyan...

This paper describes the synthesis and characterization of N5-(hetero)arylalkyl-substituted-thiazolo [5,4-d]pyrimidine-5,7-diamine derivatives (4–19) as novel human (h) A2A adenosine receptor (AR) inverse agonists. Competition binding and cyclic AMP assays indicate that the examined compounds b...

A novel Pd(II)-catalyzed dehydrogenative cross-coupling reaction of thiazolo[5,4-d]pyrimidine with unactivated (hetero)arenes via C–H bond activation was achieved. This protocol provides a straightforward and operationally simple method for the synthesis of 2-arylsubstituted thiazolo[5,4-d]pyri...

Stannylation reaction of 1-(t-butyl)dimethylsilyl-2,2-difluoroethenyl p-toluenesulfonate 1b with hexabutylbistin in the presence of 3 mol% Pd2(dba)3, 6 mol% XPhos and 30 equiv LiBr in THF at reflux temperature for 8 h provided the corresponding 1-(t-butyl)dimethylsilyl-2,2-difluoroethenylstannan...

The reaction of 1,2-C6H4(SiMe2H)(SiH3) (1) with Pt(dmpe)(PEt3)2 (dmpe = Me2PCH2CH2PMe2) in the ratio of 1:1 yields the complex {1,2-C6H4(SiMe2)(SiH2)}PtII(dmpe) (2), which has unique reactivity towards sterically unhindered phenol to form an unusual diphenoxy substituted (bis)silyl platinum(II) ...