Organolithium compounds are widely used as reagents in organic and organometallic synthesis. Since organolithium compounds usually form ag­ gregates in solution, their reactivity is drastically reduced. Therefore, donor reagents are added to the reaction mixture, which coordinate to the lithium atoms and thus break up the aggregates. The result is a considerable enhancement in reac­ tivity (and...

Chemical investigation of aerial parts of Schkuhria pinnata var wislizeni (Asteraceae) allowed the characterization of the sesquiterpene lactones 1, 2 and 5, the flavonoids 3 and 4, and the acyl phenyl propanoids 10 and 11. Structure 2, named dischkuhriolin, was confirmed as a Diels Alder adduct of 1 as dienophile and a guaianolide as diene. Spectroscopic analysis of 5 and its diacetyl derivati...

1,2-Dichloro-3,3,4,4,5,5-hexafluorocyclopentene (F 6 cypCl 2 ) was functionalized with diphenyl- and dimesitylphosphanyl groups by a salt-elimination reaction of the respecttive chlorophosphane (PPh Cl, PMes Cl) in situ generated lithiated F cyp(Li)Cl. cyp(PR )Cl (R = Ph, Mes) functionalised again to obtain corresponding trimethylstannyl substituted compounds )(SnMe 3 Mes). These tin-precursors...

A new general methodology for the synthesis of various functionalized privileged oxygen heterocyclic scaffolds, viz. pyrones, coumarins, and benzannulated coumarins, is developed. The synthesis proceeds through carbanion-induced ring transformation of lactones with various methylene carbonyl compounds followed by DDQ-mediated unprecedented oxidative cleavage of oxaylidenes intermediates. Studie...

Mammary epithelial cells from rats and humans show both quantitative and qualitative species- and carcinogen-specific differences in their abilities to activate benzo(a)pyrene (B(a)P) and 7,12-dimethylbenz(a)anthracene (DMBA). Previous studies of the DNA binding of these compounds in mammary epithelial cells demonstrated that rat cells bound relatively more DMBA than B(a)P to DNA under identica...

objective: with consideration of lethal effects of aflatoxins specially b1 on human health. estimation of aflatoxin-albumin adduct, as an important marker of aflatoxin exposure, seems essential. the aim of this study is optimization of hplc-fluorescence method for measurement of this important marker in blood serum. materials and methods: in this study, blood serum of three groups of rats as a...