Human uracil DNA glycosylase (hUNG) follows an extended reaction coordinate for locating rare uracil bases in genomic DNA. This process begins with diffusion-controlled engagement of undamaged DNA, followed by a damage search step in which the enzyme remains loosely associated with the DNA chain (translocation), and finally, a recognition step that allows the enzyme to efficiently bind and exci...

a kinetic method developed for the determination of ultra-trace amounts of nitrite based on its catalytic effect on the reaction between potassium bromate and nile blue a in strongly acidic media is reported. the reaction was monitored spectrophotometrically by measuring the decrease in absorbance of nile blue a at 645 nm by the fixed-time method. the decrease in absorbance during the first 0.5...

Coupling reaction between electron-rich 2-morpholino-4(3H)-pyrimidinone and nucleophilic side chains of several natural α-amino acids promoted by phosphonium salt has been developed to prepare new optically active pyrimidin-4-yl amino acids. The best results were obtained using a two-step method through the easily available benzotriazolyl-1-oxy intermediate. A detailed optimization study of thi...

[reaction: see text] The catalytic enantioselective electrophilic fluorination promoted by quaternary ammonium salt from cinchonine as a phase-transfer catalyst is described. Treatment of beta-keto esters with N-fluorobenzenesulfonimide as the fluorine source under mild reaction conditions afforded the corresponding alpha-fluoro beta-keto esters in exellent yields with good to moderate enantiom...

Mononuclear Pt(II) and the first dinuclear Pt(II) complexes along with a cyclometalated heterobimetallic Ir(III)/Pd(II) complex bearing mesoionic carbene donor ligands are presented starting from the same bis-triazolium salt. The mononuclear Pt(II) complex possesses a free triazole moiety which is generated from the corresponding triazolium salt through an N-demethylation reaction, whereas the ...

-lactam fused enediynes have been successfully synthesized by intramolecular Kinugasa reaction in moderate yields. DSC studies indicated significant influence of the -lactam ring upon the reactivity of enediynes. None of the -lactam fused enediynes (under ring opening conditions) as well as the 11-membered monocyclic enediyne as the tosylate salt showed any cleavage of plasmid DNA. Interestingl...

The reaction of [(PPh(2)=S)(2)CH(2)] (1) with MeLi followed by a salt elimination reaction with GeCl(4) in toluene afforded a novel germanium bismethanediide complex, 2. The structure of compound 2 has been determined by X-ray crystallography. The topological analysis of the electron densities of compound 2 was performed.

Direct liquid-phase sulfonation of methane to methanesulfonic acid (MSA) with SO2 has been achieved in triflic acid using K2S2O8 as the oxidant and a small amount of a Ca salt as the promoter. The effects of reaction conditions on the conversion of SO2 to MSA were examined. Included were the influence of solvent acidity, reaction duration, reaction temperature, amount of K2S2O8, and composition...

The salt-free water washings of a sensitized motile bacterium (B. aertrycke) were found to cause a floccular agglutination in the presence of both whole and deflagellated antigen. Evidence was presented that the water washings when salt-free contained flagella and flagellar agglutinin and that clumping occurred upon the addition of saline. The floccular reaction in the presence of deflagellated...

There has been considerable interest in the pro­ ducts of the reaction of 2 ,2 '-bipyridine with di­ bromoalkanes. The bridged diquaternary salt (1) from 2 ,2 '-bipyridine and 1 ,2 -dibromoethane is the well-known herbicide diquat dibromide [1]. Similar bridged salts are obtained with 1,3-dibromopropane and 1,4-dibromobutane [2] but reaction of 2,2'-bipyridine with 1,5-dibromopentane gives inst...