The catalytic synthesis of nitrogen-containing heterocycles is of great importance to medicinal and synthetic chemists, and also a challenge for modern chemical methodology. In this paper, we report the synthesis of pyrazolidine derivatives through a domino aza-Michael/hemiacetal sequence with chiral or achiral secondary amines as organocatalysts. Thus, a series of achiral pyrazolidine derivati...

Abstract A strategy is developed to modify cellulose nanofibril (CNF) surfaces with a combination of Cu 0 -mediated radical polymerization (SET-LRP) and I -catalyzed azide-alkyne click-chemistry (CuAAC). CNFs were grafted statistical copolymers di(ethylene glycol) ethyl ether acrylate (DEGEEA) acrylic acid 3-trimethylsilyl-prop-2-ynyl ester (TMSPgA) that allows labeling multiple fluorescent dye...

This paper deals with the design of observers for batch processes and the tuning of the observer gains with the objective to guarantee fast convergence of the state estimates. The approach followed in the present proposes to use an ITSE (Integral of the Time-weighted Square Error) criterion. The approach is illustrated on a batch process used in wastewater treatment, sequencing batch reactor (S...

Diphenyl(2-hydroxy-phenyl)phosphine was introduced as a ligand for gold(I) halides and pentafluorophenyl gold(I) in order to probe the interplay of intraand intermolecular interactions based on aurophilic (Au Au) and hydrogen bonding. 1:1 complexes of the type Ph2(2-HOC6H4)P-Au-X with X = Cl, Br, C6F5 have been prepared and characterized by analytical and spectroscopic data. The crystal structu...

Capillary gas-liquid chromatographic separation was studied for the complete set of the 26 theoretically possible isomers of mono-, di-, and trihydroxylated 5 beta-cholanic acids, which differ from one another in the number, position, and configuration of hydroxyl groups at C-3, C-7, and/or C-12 in the nucleus, as well as for some of their related acids. The bile acid samples were chromatograph...

The study of acetone-extractable components from the leaf fibers of the non-wood plant abaca (Musa textilis) resulted in the isolation and identification of series of intact hydroxycinnamate esters consisting of ferulic and p-coumaric acids esterified to long-chain fatty alcohols (C20 to C28) and omega-hydroxyfatty acids (C22 to C28). These series of compounds were characterized by high-tempera...

The conversion of deuterium-labeled ceramide to cerebroside has been studied. A mixture of N-(2’+hydroxy [4’,4’,5’,5’-2H4]hexadecanoyl) D-eryfhYO-1,3-dihydroxy-2amino-4-frans-[4,5-*H2]octadecene and N-(2’-D-hydroxy hexadecanoyl) D-eryfhro-l,3-dihydroxy-2-amino-4-frans-[33Hl]octadecene was incubated with mouse brain microsomes and a UDP-galactose regenerating system. Both galactosyl ceramide and...

The marine red alga genus Laurencia is one of the richest producers of unique brominated compounds in the marine environment. The cDNAs for two Laurencia nipponica vanadium-dependent bromoperoxidases (LnVBPO1 and LnVBPO2) were cloned and expressed in Escherichia coli. Enzyme assays of recombinant LnVBPO1 and LnVBPO2 using monochlorodimedone revealed that they were thermolabile but their Km valu...

We describe an accurate, precise method for determination of total serum cholesterol by isotope dilution/mass spectrometry (IDMS) with liquid-chromatographic separation. After adding [3,4-13C]cholesterol to serum and hydrolyzing the cholesterol esters, we extract the total cholesterol. "High-performance" liquid chromatography (HPLC) is used to separate the extracted cholesterol for measurement ...

We sought evidence for the occurrence and seasonal variation of indole-3-acetic acid (IAA) in shoots of Douglas fir (Pseudotsuga menziesii [Mirb.] Franco).Collections obtained in December and June were extracted with methanol and diethyl ether. Extracts were purified by solvent partitioning and with Sephadex LH-20. Qualitative and quantitative information was acquired by gas-liquid chromatograp...