Pico-second time-resolved luminescence spectra of excitonic molecules in CuCl

Transient luminescence behavior of excitonic molecules in CuCl is studied at 4.2 K with a time resolution of ～ 10 ps. The lifetime of the excitonic molecule state is determined to be several hundred pico-seconds. The spectral shape and the time characteristics of the luminescence intensity depend on excitation wavelength and also on the direction of observation. This is explained by the effect of the stimulated emission process.     

New synthetic equivalent of nitromalonaldehyde treatable in organic media

beta-Nitroenamines having a formyl group at the beta-position behave as the synthetic equivalent of unstable nitromalonaldehyde, which is a useful synthon for syntheses of versatile nitro compounds. High solubility of the nitroenamines into general organic solvents enables us to conduct reactions in the organic media accompanied by easy experimental manipulations and considerable safety. When nitroenamines are treated with 1,2-bifunctional nucleophiles such as hydrazines, hydroxylamine and glycine ester, nitrated pyrazoles, isoxazole and pyrrole-2-carboxylate were readily prepared. This methodology was also applicable to guanidines and 1,2-diamines, leading to pyrimidines and 1,4-diazepines, respectively.     

Synthesis and properties of a pyrrole-imidazole polyamide having a ferrocene dicarboxylic amide linker

A new minor groove binder 1 having a redox active ferrocene dicarboxamide linker was synthesized. The affinity of the newly synthesized compound to the target DNA was confirmed by CD titration experiments. Moreover, the redox property of 1 was also demonstrated by cyclic voltammetry. These results suggest the potential of 1 as a new tool for electrochemical gene detection technology.     

A new entry to Amaryllidaceae alkaloids from carbohydrates: total synthesis of (+)-vittatine

The stereoselective and chiral synthesis of the Amaryllidaceae alkaloid, (+)-vittatine 1, is described; the quaternary carbon in 1 was generated by Claisen rearrangement of a cyclohexenol derived from D-glucose by way of a Ferrier's carbocyclisation reaction and a hexahydroindole skeleton was effectively constructed by intramolecular aminomercuration-demercuration, followed by Chugaev reaction.     

Palladium-catalysed cascade ring expansion reaction of cyclobutanols that have a propargylic moiety with nucleophiles

Cascade ring rearrangement of four-membered ring systems containing various propargylic components by a palladium catalyst is described. The reactions of cyclobutanols that have a propargylic carbonate moiety with phenols as nucleophiles produce phenoxy-induced cyclopentanones in high yields. The reactions proceed in a regio- and diastereoselective manner to afford the substituted cyclopentanones with high selectivities. Imides also act as nucleophiles to produce the imidyl-induced products. Propargylic bromide successfully reacts with sodium alkoxides to produce the corresponding products in good yields.     

Use of polystyrene-supported DBU in the synthesis and alpha-selective glycosylation study of the unstable Schmidt donor of L-kedarosamine

In the alpha-glycosylation study of the unusual, 2-deoxy amino sugar of kedarcidin, polystyrene-supported DBU (PDBU) was found to be invaluable to the clean preparation of the highly labile Schmidt donor of l-kedarosamine. By further recognition that the C4-alcohol should be left free for favorable acceptor reactivity, we could for the first time successfully assemble the C13-O-alpha-glycoside of the ansamacrolide substructure of the kedarcidin chromophore. [reaction: see text]