Internet Electron. J. Mol. Des. 2003, 1, 000–000 Abstract In order to separate the effect of substituents into two parts, referring to the interaction of the reacting molecules and the solvation, the δ∆G, δ∆H and δ∆S reaction constants were defined and determined from the dependence of ∆G, ∆H and ∆S activation parameters on the σ substituent constants, by analogy with the Hammett equation. The ...

γ,δ-Unsaturated amino acids are the backbone of various natural products and pharmaceuticals, while quaternary α-amino also powerful enzyme inhibitors, both very important compounds in bioorganic chemistry. A highly efficient synthesis γ,δ-unsaturated esters utilizing tandem umpolung/Claisen rearrangement for α-iminoallyl was developed. This method has a wide range substrates taking account Ham...

Dependence of the hydrolysis rate a series N-methoxy-2-phenyl-1,3-oxazinanes on Hammett substituent constant phenyl ring was determined, yielding reaction ρ=−1.40±0.05. Based this information, 4-(benzoyloxy)benzaldehyde selected as protecting group for new (2R,3S)-4-(methoxyamino)butane-1,2,3-triol phosphoramidite building block. The yield preparation block well its coupling in automated oligon...

the ability of the present semiempirical quantum mechanics methods are surveyed for reproducing the transannular interaction in the bifunctional n-phenyl-5-azocanones. the am1 method is the best with the order of reliability being am1, pm3, mndo and mindo/3. am1 calculations were then carried out for quantification of transannular interaction. the n(o) ionization potential has been used for thi...

the kinetics of iodination of the phenol and substituted phenols using pyridiniumiodochloride in methanol has been studied under varying conditions. the rates show first orderkinetics each in pyridinium iodochloride and phenols. the rates of reactions are measured atdifferent temperature and activation parameters for all phenols computed. hammett plot is foundto be valid and the corrletion betw...

Xhaffer (1)) Myers and Fine (2), and Hahn and Meyer (3) adduced evidence that muscle creatine is the precursor of urinary creatinine. This was questioned by Chanutin and Kinard (4) but was conclusively proved by Bloch, Schoenheimer, and Rittenberg (5, 6) by isotope tracer evidence, which also showed that creatinine was the only normal urinary constituent containing any significant amount of bod...

Recognition of the significant role played by the sulphydryl group places a powerful tool in the hands of experimenters in cell proliferation, be they biologists, physiologists, pathologists, or others interested in this field. There are two fundamentals which must be appreciated, viz., first, -SH is the naturally occurring chemical group in cell division, as actually discovered in dividing cel...

Motivated by the need for chemical strategies designed to tune peptide fragmentation to selective cleavage reactions, benzyl ring substituent influence on the relative formation of carbocation elimination (CCE) products from peptides with benzylamine-derivatized lysyl residues has been examined using collision-induced dissociation (CID) tandem mass spectrometry. Unsubstituted benzylamine-deriva...

using a time-dependent-density functional theory (td-dft), configuration interaction singles (cis) and zerner’s intermediate neglect of differential overlap (zindo) methods, we have investigated the uv-visible spectra of one new intramolecular cyclization at before and after intramolecular attack. all structures were optimized at the b3lyp/6-311++g** level while uv-visible parameters were calcul...