Efficient access to some new pyrimidine derivatives and their antimicrobial evaluation

1-[4-(3-Hydroxyphenyl)-6-methyl-2-thioxo-1,2,3,4-tetrahydropyrimidin-5-yl]ethanone ( 1 ) was used as a precursor for heterocyclic synthesis. Condensation of compound 1 with monochloroacetic acid and benzaldehyde gave thiazolopyrimidine 2 which in turn underwent cyclization with malononitrile dimmer to afford malononitrile derivative 3 . Also, the reaction of compound 1 with benzaldehyde under a basic condition produced chalcone 4 . Chalcone 4 can be used as a key intermediate for further preparation of heterocyclic compounds. In addition, compound 1 was allowed to react with malononitrile dimmer and/or ethyl chloroacetate to give pyrimidines 8 and 9 , respectively. Alkylation of compound 8 with ethyl chloroacetate afforded S-alkylated product 10 which was treated with hydrazine hydrate to yield the hydrazino derivative 11 . Alternative synthesis of compound 10 was taken place through reaction of compound 9 with malononitrile dimmer. The biological activity of the synthesized compounds was investigated. Compounds 1 , 4 , 5 , and 8 recorded high activities against Gram positive bacteria (S. aureus). Structures of the new synthesized compounds were elucidated by elemental analysis and spectral data.     

Synthesis and Antimicrobial Activity of Some New Heterocyclic Schiff Bases Derived from 2-Amino-3-formylchromone

Some new hydrazone derivatives 3a–e have been obtained from 2-amino-3-formylchromone (1). Heterocyclization of thiocarbohydrazone derivative 3e via reaction with some electrophilic reagents afforded 1,2,4-triazoles 6–8 and 1,2,4-triazines 9–13. Condensation reactions of aldehyde 1 with o-aminoaldehydes and/or ketones afforded some new isolated and condensed heterocyclic systems 17, 19, and 20. The newly synthesized compounds were screened for their antimicrobial activity.     

Synthesis and characterization of benzothiazol-2-one derivatives as anti-inflammatory and analgesic agents

A series of new compounds bearing a 1,3-benzothiazol-2-one nucleus have been synthesized using 5,6-dimethyl-3-(2-oxo-propyl)-1,3-benzothiazol-2-one (1) as a key starting compound. The reaction of 1 with some nucleophilic compounds led to the formation of compounds 2, 3, 4, 5a, b, 6 and 7a, b. The thiosemicarbazone derivatives 7a, b were treated with a number of halo ketones to produce the new heterocyclic compounds 9–13, while their reaction with acid anhydrides led to the formation of the derivatives 14 and 15. Also, compound 1 was condensed with different aromatic aldehydes to afford the corresponding chalcones 18–22. The structures of all the novel compounds have been determined by analytical and spectral data. Some of the compounds were selected to be evaluated as anti-inflammatory and analgesic agents.     

Electro-optics of colloid-polyelectrolyte complexes: counterion release from adsorbed macromolecules

Complexation between sodium carboxymethylcellulose (NaCMC) and ellipsoidal particles of oppositely charged beta-FeOOH is studied using electric light scattering and electrophoresis. We focus on the complex behavior for overcharging of the particle surface. In this case, the fraction of condensed counterions on NaCMC is found to remain unchanged during polymer adsorption onto a weakly charged particle surface. Using the theory of Sens and Joanny, we evaluate the fraction of condensed counterions and compare it with results for nonadsorbed NaCMC. The polarization of condensed counterions along the chain of the adsorbed macromolecule is proved to create the electro-optical effect in suspensions stabilized by NaCMC adsorption.     

Subcritical Extracts from Major Species of Oil-Bearing Roses—A Comparative Chemical Profiling

A comprehensive chemical profiling of 1,1,1,2-tetrafluoroethane (freon R134a) subcritical extracts from the main genotypes of oil-bearing roses, was performed by gas chromatography–mass spectrometry (GC/MS) and gas chromatography with flame ionization detection (GC-FID) in order to reveal the differences in their chemical composition. One hundred and three individual compounds were identified using GC/MS and their quantitative content was determined using GC-FID, representing 89.8, 92.5, 89.7 and 93.7% of the total content of Rosa gallica L., Rosa damascena Mill., Rosa alba L. and Rosa centifolia L. extracts, respectively. The compounds found in the extracts are representatives of the following main chemical classes: mono-, sesqui- and triterpenoids, phenylethanoids and phenylpropanoids and aliphatic hydrocarbons. Fatty acids, esters and waxes were found, as well. The study revealed that 2-phenylethanol is the most abundant component, ranging 9.0–60.9% followed by nonadecane and nonadecene with 5.1–18.0% geraniol (2.9–14.4%), heneicosane (3.1–11.8%), tricosane (0.1–8.6%), nerol (1.3–6.1%) and citronellol (1.7–5.3%). The extracts demonstrate a specific chemical profile, depending on the botanical species—phenylethanoids and phenyl propanoids are the main group for R. damascena, aliphatic hydrocarbons for R. alba and R. centifolia, while both are found in almost equal amounts in R. gallica. The terpenoid compounds show relatively broad variations: monoterpenes—11.9–25.5% with maximum in R. centifolia; sesquiterpenes—0.6–7.0% with maximum in R. gallica and triterpenes—0.4–3.7% with maximum in R. gallica extract.     

Synthesis and Antimicrobial Activity of Some 3-Substituted-5,6-dimethoxy-2,3-dihydrobenzo[d]thiazol-2-one

Sixteen new compounds derived from the 2,3-dihydrobenzo[d]thiazol-2-one template with various side-chains in position-3 were synthesized and evaluated for their antimicrobial activity. Antibacterial and antifungal screening of the compounds prepared showed that 5,6-dimethoxy-3-(2-oxo-propyl)-2,3-dihydrobenzo[d]thiazol-2-one (3g) exhibited the highest activity.     

First Synthesis of Thiophene Thioglycosides

A new method for the preparation of a new class of thiophene thioglycosides via one-pot reaction of the sodium thiophenethiolate salts with 2,3,4,6-tetra-O-acetyl-α-D-gluco- and galacto-pyranosyl bromides has been studied. The sodium thiophenethiolate salts are prepared using cyano-di-thioic analogs and their corresponding mono- and dithiolate salts.     

A Direct Route to a New Class of Acrylamide Thioglycosides

The preparation of a new class of acrylamide thioglycosides via one‐pot reaction of the potassium 2‐cyanoethylene‐1‐thiolate salts with 2,3,4,6‐tetra‐O‐acetyl‐α‐D‐gluco‐ and galactopyranosyl bromides has been studied. The E‐configuration of these thioglycosides was proven by their transformations to the corresponding 5‐aminopyrazoles.