(E)-3-Ylideneoxindoles are prepared in methanol in reasonable to good yields, as adducts of photochemical 5-exo-trig of aryl radicals, in contrast to previously reported analogous radical cyclizations initiated by tris(trimethylsilyl)silane and azo-initiators that gave reduced oxindole adducts.

Cross reacting antibodies can cause an overestimation of the results of immunoassays. Therefore, alternative methods are needed for the accurate quantification of steroids. Gas chromatography combined with isotope-dilution mass spectrometry (GC-IDMS) is developed to quantify urinary active androgens, testosterone, epitestosterone and dihydrotestosterone, which are clinically relevant androgens ...

A sensitive and quantitative gas chromatographic assay for the determination of 18 beta-glycyrrhetinic acid (18 beta-GA), the main metabolite of glycyrrhizin after oral licorice consumption in human urine, has been developed and validated. For the extraction of 18 beta-GA from urine two Sep-Pak C18 extractions, hydrolysis with Helix pomatia and three liquid-liquid extractions were performed, us...

A sensitive electron-capture gas-liquid-chromatographic method for the determination of sub-nanogram quantities of prostaglandin F(2alpha) was developed. The method is based on the sub-microgram scale conversion of the prostaglandin into the electron-capturing pentafluorobenzyl ester, and analysis of the latter as the tris-trimethylsilyl ether. The lower limit of detection was 12.5pg of the est...

The development of (trimethylsilyl)ethyl ester protected enolates is reported. The application of this class of compounds in palladium-catalyzed asymmetric allylic alkylation is explored, yielding a variety of α-quaternary six- and seven-membered ketones and lactams. Independent coupling partner synthesis engenders enhanced allyl substrate scope relative to traditional β-ketoester substrates; h...

The addition of 4-trifluoromethyl-1-ethynylbenzene, phenylacetylene, or 4-ethynylanisole to P-mesityldiphenylmethylenephosphine, 1, produced photoluminescent 1,2-dihydrophosphinines 4a-c, respectively, in quantitative yield via a [4 + 2] cycloaddition. Limited reactivity was observed between 1 and non-aromatic alkynes. P-[Bis(trimethylsilyl)amino][(trimethylsilyl)methylene]phosphine, 2, and P-m...

Synthesis of azido(trimethylsilyl)acetylene (6) was performed by treating the iodonium salt 5 with highly soluble hexadecyltributylphosphonium azide (QN₃) at -40 °C. Although this product is very unstable, it can nevertheless be trapped by the click reaction with cyclooctyne to give the corresponding 1,2,3-triazole, and also directly characterized by ¹H- and (13)C-NMR data as well as IR-spectra...

The palladium catalysed 5-arylation of 2-(trimethylsilyl)thiophene with aryl bromides via C-H bond functionalisation allows the synthesis of arylated silylthiophenes in only one step.

1,1’-(ethane-1,2-diyl)dipyridinium bistribromide (edpbt) was used as a chemoselective and effective organocatalyst for the silylation of hydroxyl groups as well as desilylation of trimethylsilyl ethers under mild conditions at room temperature with good to excellent yields.