Photostable and bright fluorescent dyes with large Stokes shifts are widely used as markers in far-field optical microscopy, but the variety of useful dyes is limited. The present study introduces new 3-heteroaryl coumarins decorated with a primary phosphate group (OP(O)(OH)(2)) attached to C-4 in 2,2,4-trimethyl-1,2-dihydroquinoline fragment fused with the coumarin fluorophore. The general syn...

Synthesis of Trimethyl Chitosan Nanoparticles Containing Recombinant BLF1-stxB Protein Burkholderia Pseudomallei and Evaluation its Immunogenicity in Mice

The thermochemistry and kinetics of organophosphorus compounds were studied, with BAC-MP4 method estimations as a basis and PM3 semi-empirical estimations for many new compounds. New group additivity values were proposed for enthalpies of formation at 298 K, and entropies and heat capacities of species involving pentavalent phosphorus bonded to carbon, hydrogen, oxygen, fluorine, nitrogen, and ...

A "trimethyl lock" system has been known to facilitate lactonization reactions through what has been termed a stereopopulation control mechanism. We have found that a similar trimethyl lock system can also facilitate cyclic ether formation with the concomitant release of a carboxylic acid in the presence of anhydrous tetrabutylammonium fluoride. To study this base-mediated trimethyl lock-facili...

The conformations of the N-H and C=O bonds in the SO(2)-NH-CO-C group of the title compound (N4BPSTMAA), C(11)H(14)BrNO(3)S, are trans to each other, similar to what is observed in N-(4-chloro-phenyl-sulfon-yl)-2,2,2-trimethyl-acet-amide (N4CPSTMAA) and 2,2,2-trimethyl-N-(4-methyl-phenyl--sulfon-yl)acetamide (N4MPSTMAA). The bond para-meters in N4BPSTMAA are similar to those in N4CPSTMAA, N4MPS...

We present here the synthesis of a highly O-carboxymethylated chitosan derivative. First, an improvedprotocol for the two-step synthesis of N-trimethyl chitosan (TMC) from chitosan was developed, yield-ing a maximum degree of quaternization (DQ) of up to 46.6%. Successively, the chitosan derivativeO-carboxymethyl-N-trimethyl chitosan (CMTMC) was synthesized from the TMC obtained by applyingan o...

The proposed work describes the nanodrop spectrophotometric determination of cationic surfactants using citrate-modified silver nanoparticles based on the aggregation of silver nanoparticles induced by cationic surfactants due to the hydrophobic effect. The visible color change in the solution of silver nanoparticle includes a red shift with the quenching of the absorption spectra. The maximum ...