Great effort has been devoted to the development of new strategies for glycosidic coupling owing to the growing importance of synthetic oligosaccharides in glycobiology.1 In the past decades, methods for construction of glycosidic linkages have progressed considerably.2 However, compared to the synthesis of oligopeptides and oligonucleotides, the synthesis of oligosaccharides is still laborious...

By an ortho-radial drawing of a graph we mean a planar drawing on concentric circles such that each edge is an alternating sequence of circular and radial segments, where a circular segment is a part of a circle and a radial segment is a part of a half-line starting at the center of the circles. Ortho-radial drawings are topologically an extension of orthogonal drawings to drawings on a cylinde...

The tetra azophenylcalix[4]arene with ortho-ester group was applied for determination of transition metal ions using spectrophotometer. In this case, the derivatives with ortho-ester group turned out the complexing formation selectively with transition metal ions over alkali, alkaline earth metal ions. From those, this study used the molecular mechanic method MM+ and molecular dynamic simulatio...

Exposure to polycyclic aromatic hydrocarbons (PAHs) is the major human health hazard associated with the Deepwater Horizon oil spill. C2-Chrysenes are representative PAHs present in crude oil and could contaminate the food chain. We describe the metabolism of a C2-chrysene regioisomer, 6-ethylchrysene (6-EC), in human HepG2 cells. The structures of the metabolites were identified by HPLC-UV-flu...

The induction of ethoxyresorufin-o-deethylase (EROD) activity by binary combinations of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and seven polychlorinated biphenyls (PCBs) was examined in liver cell lines from rat (H4IIE) and rainbow trout (RTL-W1). The non-ortho PCBs were 77, 81, 126, and 169; the mono-ortho PCBs were 105, 118, and 156. Binary combinations yielded less-than-additive interact...

Recently, several bis-pyridiniumaldoximes linked by a variable-length alkylene chain were rationally designed in our laboratories as cholinesterase reactivators. Extensive in vitro tests of these oximes with acetylcholinesterase inhibited by two different organophosphate agents, echothiophate and diisopropylfluorophosphate, revealed one compound with particularly good reactivation kinetics and ...

The use of methanesulfonic acid as a Brønsted acid for direct ortho-acylation of phenols and naphthols proves to be a convenient, more general and direct route to various hydroxyaryl ketones. The route is regioselective, leading to ortho C-acylated products in satisfactory to high yields in most cases. The solvent free reactions described below exhibited environmentally benign in terms of faste...

The tetrahydride complex OsH4{xant(PPr2)2} (1, xant(PPr2)2 = 9,9-dimethyl-4,5bis(diisopropylphosphino)xanthene) activates an ortho-C-H bond of benzophenone and acetophenone to give the osmaisobenzofuran derivatives OsH{κ-C,O-[C6H4C(R)O]}{xant(PPr2)2} (R = Ph (2), CH3 (3)). The reaction of 1 with perdeuterated benzophenone leads to 2 partially protiated. The deuterium distribution in the latter ...

Two types of enantioselective [2 + 2 + 2] cycloadditions of triynes using chiral rhodium catalysts are disclosed. The intramolecular reaction of ortho-aminophenol-tethered triynes provides chiral tripodal compounds. Consecutive interand intramolecular reactions of ortho-phenylene-tethered triynes provide chiral tetraphenylenes.

A practical Cu-catalyzed direct ortho-halogenation of anilines under aerobic conditions has been developed. The reaction shows typically excellent mono-substitution selectivity, high ortho-regiocontrol and large functional group tolerance.