Novel coumarin derivatives, 2-oxo-2H-chromenecarbaldehyde hydrazones were prepared by reaction of substituted 2-oxo-2H-chromenecarbaldehydes with N-aminoimides in ethanol in the presence of 4-toluenesulfonic acid as catalyst. The photochromic and thermochromic properties of the prepared compounds were investigated.

Gold nanoparticles supported on TiO(2) (~1%) catalyse in high yields the selective cycloisomerisation of aryl propargyl ethers into the corresponding 2H-chromenes, under heterogeneous conditions. 2H,2'H-3,3'-Bichromenes resulting from a catalytic oxidative dimerization pathway are also formed as by-products.

The compounds, 3,6-dimethoxypyridazine, l,2-dimethyl3,6(1H,2H)-pyridazinedione, and 6-methoxy-2-methyl-3(2H)pyridazinone, were prepared by using reported preparations. Their photochemistry was investigated and compared to the thermal chemistry and photochemistry of maleic hydrazide. , I' 1.!. t, 1, 1 I, I : vii

Changes in potassium (K) concentration in erythrocytes (RBC) were investigated during the early developing stage (1 and 2 weeks after) and the chronic established stage (12 to 16 weeks after the renal artery constriction) in two-kidney (group 2H) and one-kidney Goldblatt hypertension (group 1H) of the rabbit. In both group 2H and group 1H, blood pressure was already elevated significantly durin...

The results are reported of mass-spectrometric studies of the nucleobases adenine 1h (1, R = H), guanine 2h, and cytosine 3h. The protonated nucleobases are generated by electrospray ionization of adenosine 1r (1, R = ribose), guanosine 2r, and deoxycytidine 3d (3, R = deoxyribose) and their fragmentations were studied with tandem mass spectrometry. In contrast to previous EI-MS studies of the ...

Three new Prussian blue analogues, heptanuclear mixed-valence iron complexes of the type [Fe(II)(CN)(6){Fe(III)(1(-2H))}(6)]Cl(2)·nH(2)O, were synthesized and structurally and spectrally characterized, and their magnetic properties were investigated (1(-2H) corresponds to doubly deprotoned Schiff-base pentadentate ligands 1a, N,N'-bis(2-hydroxybenzylidene)-1,5-diamino-3-azapentane, 1b, N,N'-bi...

RATIONALE Proton and radical are transferred between matrices and matrix and analyte in matrix-assisted laser desorption/ionization (MALDI) and these transfers drive ionization of analytes. The odd-electron anion [M-2H]•- was generated in dihydroxybenzoic acids (DHBs) and the ion abundance of the 2,5-DHB was the highest among six DHB isomers. We were interested in the mechanism of the ion gener...

INTRODUCTION Dipeptidyl peptidase-4 (DPP-4) inhibitors reduce hyperglycemia in patients with type 2 diabetes mellitus (T2DM) by enhancing insulin and suppressing glucagon secretion. Since T2DM is associated with progressive loss of β-cell function, we hypothesized that the DPP-4 inhibitor action to improve β-cell function would be attenuated with longer duration of T2DM. METHODS Data from six...

This study investigated anticipatory cortisol and pre-competitive anxiety of swimmers before competition. Fifteen university volunteered to participate in the study. Salivary Competitive State Anxiety Inventory-2 (CSAI-2R) were collected six days (6d) two hours (2h) Results revealed higher somatic 2h compared 6d prior No differences observed cortisol, cognitive anxiety, self-confidence. Thus, i...

A novel and efficient cascade annulation of tertiary α-hydroxy ketones and dimethyl but-2-ynedioate is reported. The reaction, which only requires a base as the promoter, provides a straightforward access to polysubstituted pyrano[4,3-a]quinolizine-1,4,6(2H)-triones and 2H-pyran-2,5(6H)-diones under very mild reaction conditions.