A new reaction of the efficient difluorocarbene-generating reagent trimethylsilyl fluorosulfonyldifluoroacetate (TFDA) is reported in which molecules containing an N-alkylimidazole or benzimidazole structure undergo an unexpected one-pot conversion to N-difluoromethylthioureas. [reaction: see text].

In multi-step organic syntheses, the protection and deprotection of tetrahydropyranyl (THP) ethers is one of the most frequently used methods. Over the years, different methods have been used from various catalytic systems for the protection of hydroxyl groups as THP ethers and their deprotection. Herein we have reported that various alcohols and phenols have been efficiently converted to the c...

A mild and efficient protocol for the deprotection of silyl ethers using KF in tetraethylene glycol is reported. A wide range of alcoholic silyl ethers can be selectively cleaved in high yield in the presence of certain acid- and base-labile functional groups. Moreover, the phenolic silyl ethers were cleaved exclusively, without affecting the alcoholic silyl ethers, at room temperature.

We have previously demonstrated the potential usefulness of capillary columns coated with a high temperature polarizable phenylmethylsilicone liquid phase in plasma lipid profiling (Kuksis, A., J.J. Myher, and P. Sandra. 1990. J. Chromatogr. 500: 427-441). The present study reports improved operating conditions along with a practical application to the analysis of a series of human plasma sampl...

A study is conducted to determine the amino acid, fatty acid, and carbohydrate content of breadfruit using high-performance liquid chromatography (HPLC) and gas chromatography (GC). An HPLC method is used for the determination of amino acids and fatty acids in breadfruit. Representative amino acid samples are derivatized with phenylisothiocianate and the resulting phenylthiocarbamyl derivatives...

Aromatase is a cytochrome P-450 enzyme complex that catalyzes the conversion of androst-4-ene-3,17-dione (AD) to estrone through three sequential oxygenations of the 19-methyl group. To gain insight into the ability of AD isomers, 4-en-6-one 1a, 5-en-4-one 2a, and 5-en-7-one 3a, competitive inhibitors of aromatase with an A, B-ring enone structure to serve as a substrate, we incubated the three...

The excretion of sulfatides in human urine was studied. 24-hr urine collections were filtered. Urinary glycolipids were extracted from the filter paper and fractionated on diethylaminoethyl cellulose and silicic acid columns, and by thin-layer chromatography. Fatty acids and long-chain bases were analyzed by gas-liquid chromatography of the corresponding esters and aldehydes. Glycosyl ceramide ...

[reaction: see text] Radical-mediated silyl- and germyldesulfonylations of various vinyl and (alpha-fluoro)vinyl sulfones with tris(trimethylsilyl)silane and germanium hydrides provide access to vinyl and (alpha-fluoro)vinyl silanes and germanes. Upon oxidative treatment with hydrogen peroxide in basic aqueous solution, the vinyl tris(trimethylsilyl)silanes and -germanes undergo Pd-catalyzed cr...

Reductions of bulky alkynyl-substituted dihalosilanes, BbtSiX(2)(C[triple bond]CR) (Bbt = 2,6-bis[bis(trimethylsilyl)methyl]-4-[tris(trimethylsilyl)methyl]phenyl, R = SiMe(3) or Ph groups, X = halogen), with 2.0 equiv. of lithium naphthalenide gave the first stable 1,2-dialkynyl-substituted disilenes, which constituted extended pi-conjugated systems between Si=Si bond and ethynylene units.