Home  About us  Contact
 

Unexpected Products (unexpected + products)

Distribution by Scientific Domains
Chemistry100%

Selected Abstracts

Thin Layer Chromatography for the Detection of Unexpected Reactions in Organometallic Combinatorial Catalysis

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 8 2003
Olivier Lavastre
Abstract Thin layer chromatography (TLC) represents a fast and inexpensive alternative to NMR spectroscopy or analytical methods based on chromatography for the detection of unexpected products in organometallic combinatorial catalysis. This screening test led to the detection of the catalytic system [Ir(COD)Cl]2/PPh3 for isomerisation of diolefinic substrates instead the expected ring closing metathesis (RCM) reaction. [source]

Automated structure elucidation of two unexpected products in a reaction of an ,,,-unsaturated pyruvate

MAGNETIC RESONANCE IN CHEMISTRY, Issue 7 2004
Gary J. Sharman
Abstract The reaction between an ,,,-unsaturated pyruvate and ethyl diazoacetate (EDA) yielded two unexpected products. The structures of these products were determined by automated elucidation of the chemical structures using spectroscopic inputs of a series of 1D and 2D NMR data using the computer program ACD/Structure Elucidator, StrucEluc. The formation of these products is rationalised. Their structures were also confirmed by x-ray crystallography. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Bioactive taxoids from the Japanese yew Taxus cuspidata

MEDICINAL RESEARCH REVIEWS, Issue 3 2002
Jun'ichi Kobayashi
Abstract A series of new taxoids, named taxuspines A,H and J,Z (1,25) and taxezopidines A,H and J,L (26,36), have been isolated together with 37 known taxoids (37,73) including paclitaxel (53) from the Japanese yew, Taxus cuspidata Sieb. et Zucc. (Taxaceae). These new taxoids possess various skeletons containing 5/7/6, 6/10/6, 6/5/5/6, 6/8/6, or 6/12-membered ring systems. Among the new taxoids, some non-taxol-type compounds remarkably reduced CaCl2 -induced depolymerization of microtubules, or increased cellular accumulation of vincristine in multidrug-resistant tumor cells as potent as verapamil. On the other hand, chemical derivatization of taxinine (37), one of major taxoids obtained from this yew, led to the discovery of unusual reactions of taxinine derivatives. Here we describe our recent results on the isolation, structure elucidation, and bioactivity of these new and known taxoids and the formation of unexpected products of the unusual reactions of taxinine. © 2002 Wiley Periodicals, Inc. Med Res Rev, 22, No. 3, 305,328, 2002; Published online in wiley InterScience (www.interscience.wiley.com). DOI 10.1002/med.10005 [source]