Tautomeric Equilibria in Solutions of 2-Phenacylbenzimidazoles

Detailed NMR spectral analysis of DMSO-d6 solutions of the series of substituted 2-phenacylbenzimidazoles (ketimine form, K) reveals two from three tautomeric forms. Integrals of the 1H NMR signals are used in establishing the molar ratio of tautomers. The experimental analyses are supported by quantum-chemical calculations, which satisfactorily reproduced the experimental trends. Although the reported semiempirical quantum-chemical calculations show that enaminone E, i.e., 2-(1,3-dihydro-2H-benzo[d]imidazol-2-ylidene)-1-phenylethan-1-one, was thermodynamically most stable, the results of MP2 ab initio calculations reveal the following order of stability: ketimine > enolimine > enaminone (substituents do not affect this sequence). 13C CPMAS NMR spectral data reveal that in the crystalline state the enolimine tautomer O is predominant in the p-CH3 and p-NO2 substituted congeners.

SYNTHESIS AND PHYSICOCHEMISTRY PROPERTIES PREDICTION OF A NEW POTENTIAL ANTI-INFLAMMATORY AGENT: DIACETYL PENTAGAMAVUNON-1

Synthesis and physicochemistry properties prediction of a potential anti-inflammatory agent, diacetyl pentagamavunon-1 (diacetyl PGV-1), has been done. The synthesis was using pentagamavunon-1 (PGV-1) (2,87x10-3 mole) and anhydride acetic acid (26x10-3 mole; 37x10-3 mole; 49x10-3 mole) as starting materials and NaOH ethanolic as a catalyst. The AM1 semiempirical quantum-chemical calculations using the computational chemistry approach was used to predict and compare the physicochemisty properties of diacetyl PGV-1 to PGV-1. Odorless, light-yellow powder has been obtained. The powder was 0.8512-0.9602 g (2.02 x10-3 - 2.22x10-3 mole; 70.4-77.4%) and the purity of the powder was 92.4%. The purity of the product has been examined by high performance liquid chromatography (HPLC), while the structure elucidation has been done using IR (Infra Red), 1H-NMR (Nuclear Magnetic Resonance) and MS (Mass Spectroscopy). The physicochemisty properties prediction showed that diacetyl PGV-1 was more hydrophobic than PGV-1. Keywords: Anti-inflammatory, PGV-1, diacetyl PGV-1, AM1

Synthesis and Characterization of Polyacriflavine

New functional polymeric, semiconducting materials were synthesized by chemical oxidative polymerization of acriflavine hydrochloride in aqueous solution at room temperature, using ammonium peroxydisulfate as an oxidant. Polymerization products were characterized by gelpermeation chromatography (GPC), FTIR spectroscopy, scanning electron microscopy (SEM) and conductivity measurements. The influence of the oxidant/monomer molar ratio on the molecular structure, molecular weight distribution and the electrical conductivity of polyacriflavines was studied. Molecular weights approach a maximum value of ~20000. The polyacriflavine prepared by using oxidant/monomer molar ratio 1.25 shows the conductivity of 2.8 × 10–7 S cm–1. New substitution pattern shown by FTIR spectroscopic analysis combined with MNDO-PM3 semiempirical quantum chemical calculations revealed N─C2 coupling reactions as dominant. The formation of phenazine rings in ladder structured polymerization products was observed by FTIR spectroscopy. The existence of a certain polyacriflavine crystalline structure was suggested from the SEM micrographs.

Quantum-Chemical Investigations of 5-Bromo-2'-Deoxyuridine Derivatives with Antiviral Activity

The article describes the results of semiempirical quantum-chemical calculations for a series of 3',5'-esters of 5-bromo-2'-deoxyuridine with amino acids or peptides. These compounds were synthesized and tested for antiviral activity as potential prodrugs of the parent 5-bromonucleoside. It was not clear why only some of the compounds were active. On the basis of structure investigation and the calculated molecular descriptors, it was found that the determining factor for obtaining appropriate prodrugs of 5-bromo-2'-deoxyuridine is the lipophilicity of the esters.