rapid and highly efficient synthesis of 2- or 2,5-substituted 1,3,4-oxadiazoles by the condensation of aryl carboxylic acid hydrazides and orthoesters can be achieved under microwave irradiation using an unmodified commercial over in unsealed vessels.

A proton transfer reaction-quadrupole interface time-of-flight mass spectrometer was combined with a hand-made thermal desorption (TD) instrument for real-time analysis of organic aerosol particles. Size-selected single-component particles were generated using nebulizer differential mobility analyzer. We tested perfluoroalkoxy alkene (PFA) and copper tubing the TD instrument. Higher signal inte...

Seven pyrrole alkaloids isolated from Agelas sponges were tested for interactions with the cellular calcium homeostasis. Brominated pyrrole alkaloids reduced voltage dependent calcium elevation in PC12 cells. Dibromosceptrin was the most potent alkaloid with a half maximal concentration of 2.8 microM followed by sceptrin (67.5 microM) and oroidin (75.8 microM). 4,5-Dibromopyrrole-2-carboxylic a...

Reactions of N-isocyaniminotriphenylphosphorane with a cyclic ketone in the presence of ferrocene carboxylic acid proceeded smoothly at room temperature and in neutral conditions to afford ferrocene-containing 1,3,4-oxadiazole derivatives in high yields. The reaction proceeded smoothly and cleanly under mild conditions and no side reactions were observed. The structures of the products were ded...

L-Alanine, L-threonine, L-valine, D-cystine and three derivatives of thiazole-4-carboxylic acid (thiostreptin, 1-aminomethylthiazole-4-carboxylic acid and thiostreptoic acid) were isolated from the acid-hydrolysate of thiopeptin B. In addition, the presence of dehydrobutyrine and dehydroalanine residues in the antibiotic was determined. Other components remain unidentified.

2-Aminobenzothiazole-6-carboxylic acid (1), on condensation with chloroacetyl chloride yielded 2-(2-chloroacetylamino)benzothiazole-6-carboxylic acid (2), which on amination with hydrazine hydrate yielded in turn 2-(2-hydrazinoacetylamino)benzo-thiazole-6-carboxylic acid (3). Compound 3, on condensation with various aromatic aldehydes afforded a series of 2-{2-[N'-(arylidene)hydrazino]acetylami...

A number of manganese-based catalysts employing ligands whose structures incorporate pyridyl groups have been reported previously to achieve both high turnover numbers and selectivity in the oxidation of alkenes and alcohols, using H(2)O(2) as terminal oxidant. Here we report our recent finding that these ligands decompose in situ to pyridine-2-carboxylic acid and its derivatives, in the presen...

A series of NiCuZnAl catalysts with various Cu/Ni molar ratios and XCuZnAl (X=Ni, Co, Mn, Mg, La) were prepared used in the aldehyde-water shift (AWS) reaction propanal as model compound. Although copper is main site for AWS reaction, some additives also showed effects on enhancing catalytic activity to varying degrees. Mn promoted catalyst highest conversion 22 % at 260 °C, much better than La...

The role played by the additives salicylic acid, L-ascorbic acid and oxalic acid in promoting the catalytic activity of [MnIV2(O)3(tmtacn)2](PF6)2 (1(PF6)2, where tmtacn = N,N',N''-trimethyl-1,4,7-triazacyclononane) in the epoxidation and cis-dihydroxylation of alkenes with H2O2 and in suppressing the catalysed decomposition of H2O2 is examined. Whereas aliphatic and aromatic carboxylic acids e...