Green synthesis of new chiral 1-(arylamino)imidazo[2,1-a]isoindole-2,5-diones from the corresponding α-amino acid arylhydrazides in aqueous medium.

New chiral 1-(arylamino)imidazo[2,1-a]isoindole-2,5-dione derivatives were obtained in good to excellent yields via the cyclocondensation of 2-formylbenzoic acid and various α-amino acid arylhydrazides using water as the solvent in the presence of sodium dodecyl sulfate as the surfactant and under simple and minimum manipulation, without purification. The reaction is totally diastereoselective and gives access to the nitrogenated tricyclic core with a relative trans stereochemistry.

New palladium-oxazoline complexes: Synthesis and evaluation of the optical properties and the catalytic power during the oxidation of textile dyes.

The present paper describes the synthesis of new palladium-oxazoline complexes in one step with good to high yields (68-95%). The oxazolines were prepared from enantiomerically pure α-aminoalcohols. The structures of the synthesized palladium complexes were confirmed by NMR, FTIR, TOFMS, UV-visible spectroscopic analysis and X-ray diffraction. The optical properties of the complexes were evaluated by the determination of the gap energy values (E g) ranging between 2.34 and 3.21 eV. Their catalytic activities were tested for the degradation of Eriochrome Blue Black B (a model of azo dyes) in the presence of an ecological oxidant (H2O2). The efficiency of the decolorization has been confirmed via UV-visible spectroscopic analysis and the factors affecting the degradation phenomenon have been studied. The removal of the Eriochrome reached high yields. We have found that the complex 9 promoted 84% of color elimination within 5 min (C 0 = 30 mg/L, T = 22 °C, pH 7, H2O2 = 0.5 mL) and the energetic parameters have been also determined.

New chiral 4-substituted 2-cyanoethyl-oxazolines: synthesis and assessment of some biological activities.

This paper describes the synthesis of new enantiomerically pure 2-cyanoethyl-oxazolines in one step starting from a wide range of amino alcohols and 4-ethoxy-4-iminobutanenitrile with high to good yields (73-96%) via an appropriate procedure which can be used for a selective synthesis of mono-oxazolines. A simple operation as well as a practical separation is additional eco-friendly attributes of this method. All the synthesized compounds were identified and characterized with their physicochemical features and their spectral data ((1)H NMR, (13)C NMR and TOFMS ES(+)). Among the prepared mono-oxazolines, the mono-oxazoline (3a) [3-[(4S)-4-benzyl-4,5-dihydro-1,3-oxazol-2-yl] propanenitrile] was tested to detect some biological activities. This compound was studied in vitro given the various types of pharmacological properties characterizing these compounds such as antioxidant, antimicrobial and analgesic activities. The antioxidant activity and mechanism of (3a) were identified using various in vitro antioxidant assays including 1,1-diphenyl-2-picryl-hydrazyl (DPPH), and superoxide anion radicals (O2(-)) scavenging activity. In addition, compared to Quercetin, the tested synthetic product reveals a relatively-strong antiradical activity towards the DPPH (activity percentage of 81.22%) free radicals and significantly decreased the reactive oxygen species such as (O2(-)) formation evaluated by the non-enzymatic (nitroblue tetrazolium/riboflavine) and the enzymatic (xanthine/xanthine oxidase) systems. Related activity values were, respectively, 66% and 60.30%. The oxazoline (3a) showed a high ability to reduce the O2(-) generation and proved to be a very potent radical scavenger. On the other hand, the analgesic property of the 3[(4S)-benzyl-4,5-dihydro-1,3-oxazol-2-yl] propanenitrile (3a) was demonstrated. The subcutaneous administration of (3a) produced a significant reduction in the number of abdominal constrictions amounting to 73.81% in the acetic acid writhing test in mice. In addition to these advances, the oxazoline (3a) has been investigated as an antimicrobial agent. Our results showed that this molecule exhibited various levels of antibacterial effect against all the tested bacterial strains.

Synthesis and pharmacological profile of 6-methyl-3-isopropyl-2H-1,2-benzothiazin-4(3H)-one 1,1-dioxide derivatives: non-steroidal anti-inflammatory agents with reduced ulcerogenic effects in the rat.

The new anti-inflammatory agents 6-methyl-3-isopropyl-2H-1,2-benzothiazin-4(3H)-one 1,1-dioxide 6a and its analogues 6b-f were synthesized from L-valine. All compounds were characterized by physical, chemical and spectral studies. Preliminary pharmacological evaluation of the resulting products showed that compounds 6a-f (5-20 mg/kg, i.p.) are active anti-inflammatory agents in carrageenan-induced rat paw oedema assay in albino rats, and their effects are comparable to that of piroxicam (5 mg/kg, i.p.), used as a reference drug. The nature of the substituents on the sulfonamide nitrogen and those on position three had a pronounced effect on the anti-inflammatory activity. Studies of structure-activity relationships have led to selection of compound 2,6-dimethyl-3-isopropyl-1,2-benzothiazin-3,4-diol 1,1-dioxide 6 f which exhibited the most potent activity (61.7% inhibition at 5 mg/kg, i.p. and ED(50)=4.5 mg/kg, i.p.). Comparison of the gastrointestinal safety of compounds 6a-f with that of piroxicam showed a far better tolerability for our products. This comparison was based on the ulcer index and the pH of gastric content.