Preparation of poly(oxybutyleneoxymaleoyl) catalyzed by a proton exchanged montmorillonite clay. (17/78)

The polycondensation of tetrahydrofuran with maleic anhydride catalyzed by Maghnite-H+ (Mag-H) was investigated. Maghnite is a montmorillonite sheet silicate clay that is exchanged with protons to produce Maghnite-H [1]. It was found that the polymerization in bulk is initiated by Mag-H in the presence of acetic anhydride at 40 degrees C. The effects of the amounts of Mag-H and acetic anhydride were studied. The polymerization yield increased as the proportions of catalyst and acetic anhydride were increased.  (+info)

A novel derivative for the assessment of urinary and salivary nitrate using gas chromatography/mass spectrometry. (18/78)

 (+info)

Generation of hyperpolarized substrates by secondary labeling with [1,1-13C] acetic anhydride. (19/78)

 (+info)

Microwave-assisted solvent-free acetylation of cellulose with acetic anhydride in the presence of iodine as a catalyst. (20/78)

 (+info)

Chemical modification of lysine residues in lysozyme may dramatically influence its amyloid fibrillation. (21/78)

 (+info)

Confirming urinary excretion of mephentermine and phentermine following the ingestion of oxethazaine by gas chromatography-mass spectrometry analysis. (22/78)

Mephentermine and phentermine, substances prohibited in sports by the World Anti-Doping Agency, were found for the first time in urine specimens following the administration of a therapeutic medication, oxethazaine. In a recent sporting event, a urine specimen donor who tested positive for mephentermine and phentermine claimed consumption of Mucaine((R)) for treating stomach pain was the reason for testing positive. Five volunteers were administrated oxethazaine (a topical anesthetic found in the multi-ingredient medication Mucaine and its generic equivalent, Stoin, both of which are available in Taiwan), mephentermine, and phentermine. Excretion profiles of mephentermine and phentermine following the administration of these drugs were found to be similar. However, the mephentermine/phentermine ratios found in urine specimens collected at different time points following the administration of oxethazine and mephentermine were found to be characteristically different.  (+info)

Tandem processes identified from reaction screening: nucleophilic addition to aryl N-phosphinylimines employing La(III)-TFAA activation. (23/78)

 (+info)

Efficient diacetoxylation of alkenes via Pd(II)/Pd(IV) process with peracetic acid and acetic anhydride. (24/78)

 (+info)