The excitation/de-excitation step in the Lindemann mechanism is investigated in detail using model development and classical trajectory studies based on a realistic potential energy surface. The model, based on a soft-sphere/line-of-centers approach and using elements of Landau-Teller theory and phase space theory, correctly predicts most aspects of the joint probability distribution P(ΔE,ΔJ) f...

Novel synthesis of diversely substituted 2-(furan-3-yl)acetates via palladium-catalyzed one-pot multi-component reactions of allenols, aryl iodides, alcohols, and carbon monoxide has been developed. Notably, the formation of the title compounds features a cascade process combining carbonylation of aryl iodide, alcohoxyl carbonylation of the in situ formed allyl palladium complex, and intramolec...

By the synergistic catalysis of samarium ion and mercaptan, a series of 5-oxoalkanals was converted to (substituted) delta-lactones in efficient and stereoselective manners. This one-pot procedure comprises a sequence of acetalization, Tishchenko reaction and lactonization. The deliberative use of mercaptan, by comparison with alcohol, is advantageous to facilitate the catalytic cycle. The reac...

Silacyclic derivatives of heteroaromatic sulfides have been prepared by using phase transfer catalytic (PTC) system thiol / silacyclopropyl iodide / solid K(2)CO(3) / 18-crown-6 / toluene. The target sulfides were isolated in yields up to 70 %. The S-derivatives of N-methylimidazolyl, benzoxazolyl and 1,3,4-triazolyl thiols selectively lowered the low density lipoprotein (LDL) level in mice wit...

A regional air assessment was performed to characterize volatile natural isothiocyanate (NITC) compounds in air during soil incorporation of mustard cover crops in Washington State. Field air sampling and analytical methods were developed specific to three NITCs known to be present in air at appreciable concentrations during/after field incorporation. The maximum observed concentrations in air ...

A new annulation strategy for the synthesis of trans-bicyclic sulfamides is described. The Pd-catalyzed alkene carboamination reactions of 2-allyl and cis-2,5-diallyl pyrrolidinyl sulfamides with aryl and alkenyl triflates afford the fused bicyclic compounds in good yields and with good diastereoselectivity (up to 13:1 dr). Importantly, by employing reaction conditions that favor an anti-aminop...

The allyl and propenyl ethers of diols and polyols have recently attracted increasing attention as monomers and comonomers [1–2]. Most convenient method of the preparation of propenyl ethers consists in isomerization of the corresponding, readily available allyl ethers. Moreover, this isomerization is a key step of deprotection of hydroxyl group, protected as allyl ether [3,4]. Particularly con...

Protection of Escherichia coli NIHJ and C57BL mice from the effects of 60Co gamma-rays provided by S-alk(en)yl-L-cysteines and their hydantoin derivatives was examined. E. coli (10(6) cells/ml) suspended in a 20 mM aqueous solution of one of the drugs was irradiated with 60 Gy of gamma-rays. Five week-old male mice were exposed to 5.0-9.5 Gy of gamma-rays after a single intraperitoneal injectio...

Betulin derivatives are a widely studied group of compounds of natural origin due to their wide spectrum of biological activities. This paper describes new betulin derivatives, containing a phosphonate group. The allyl-vinyl isomerization and synthesis of acetylenic derivatives have been reported. Structural identification of products as E and Z isomers has been carried out using ¹H-, (13)C-, (...

Ultraperformance liquid chromatography coupled with negative electrospray tandem mass spectrometry (UPLC-ESI-MS/MS) was used to determine 7 hydroxy fatty acids in the pollen of Brassica campestris L. var. oleifera DC. All the investigated hydroxy fatty acids showed strong deprotonated molecular ions [M-H](-), which underwent two major fragment pathways of the allyl scission and the β-fission of...