An efficient, mild and metal free l-proline catalyzed construction of fused pyrimidines under microwave conditions in water.

One-pot condensation of 4-hydroxy coumarins, aldehydes and urea/thiourea to build C-C and C-N bonds is described. Fused pyrimidines have been synthesized under mild reaction conditions using l-proline. The protocol has been performed rapidly and efficiently in water under metal free conditions. Heterocyclic derivatives have been synthesized using the present methodology and avoid the use of hazardous solvents over conventional organic solvents. A proposed mechanism could be established for three component reactions. The present study reveals the first case in which l-proline has been explored as a homogeneous catalyst in the synthesis of fused pyrimidines in water under microwave irradiation. This synthesis involves simple workup and acceptable efficiency. The most notable feature of this protocol is the ability of the catalyst to influence asymmetric induction in the reaction.

Metal-Free Construction of Fused Pyrimidines via Consecutive C-C and C-N Bond Formation in Water.

A facile and efficient protocol has been developed for mild construction of fused pyrimidines via l-proline-catalyzed reaction of 4-hydroxy coumarins, aldehydes, and 2-aminobenzothiazoles/urea. The reaction has been carried out rapidly and efficiently in water under mild and metal-free conditions. Current etiquette has efficiently synthesized the heterocycles and avoids the use of hazardous solvents over conventional organic solvents. A plausible reaction mechanism has been established in this study. This study represents the first case in which l-proline as a homogeneous catalyst has been explored in the synthesis of fused pyrimidines in water in view of simple procedure and acceptable efficiency. This method gives the target product in excellent yield with ease of workup.

Sustainable Synthesis and Characterization of Ni-Al-Containing Double-Layered Nanocatalysts and Their Catalytic Activity.

Sustainable synthesis of Ni-Al double-layered catalysts by the coprecipitation method is described. Synthesized double-layered catalysts have been characterized by X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared, and thermogravimetric analyses, which confirmed a hydrotalcite-like structure. In addition, the impact of aging time and temperature on the activity of catalyst has been investigated. Furthermore, it has been confirmed by SEM and TEM analyses that the recovered catalyst has retained its structure. It has also been observed that the prepared material has potency to catalyze the reaction without loss in the yield. To explore the reactivity of the material, the catalyst has been examined in the synthesis of N-(2-hydroxyphenyl)benzamide under solvent-free conditions. The overall process afforded the product with high purity and high yields within short time.

One-pot facile and mild construction of densely functionalized pyrimidines in water via consecutive C-C and C-S bonds formation.

Fused pyrimidines composed of alternating heteroatoms and a pyrimidine moiety were synthesized efficiently using readily available starting material 4-hydroxycoumarin, aromatic aldehydes, and urea/thiourea at room temperature. Acid, metal salts, and surfactants were screened for their influence on catalytic activity in three-component reactions and sodium lauryl sulphate (SLS) was used as the best catalyst with different concentrations. Screening results of catalyst loading from our investigation showed that good to excellent yields were obtained with 10 mol%. Our method efficiently synthesized heterocycles and avoided the use of hazardous solvents and conventional organic solvents. Our procedure which involves a surfactant is operationally simple, environmentally benign, has excellent yields, short reaction times, and synthetically is as efficient as conventional procedures using organic solvents.

Structure activity relationship, cytotoxicity and evaluation of antioxidant activity of curcumin derivatives.

Series of curcumin derivatives/analogues were designed and efficient method for synthesis thereof is described. All the synthesized compounds have been screened for their cytotoxicity and evaluated their antioxidant activity. Cytotoxicity effect has been evaluated against three cell lines Hep-G2, HCT-116 and QG-56 by MTT assay method. Structure activity relationship has revealed that particularly, compound 3c, (IC50 value 6.25 µM) has shown better cytotoxicity effect against three cell lines. According to results of SAR study, it was found that 4H-pyrimido[2,1-b]benzothiazole derivatives (2e and 2f), pyrazoles (3a, 3b, 3c and 3d) benzylidenes (4d) exhibited better antioxidant activity than curcumin. A correlation of structure and activities relationship of these compounds with respect to drug score profiles and other physico-chemical properties of drugs are described and verified experimentally.

Biological activity, design, synthesis and structure activity relationship of some novel derivatives of curcumin containing sulfonamides.

Five series of curcumin derivatives with sulfonamides 3a-3e, 4a-4e, 5a-5e, 6a-6e and 7a-7e have been synthesized and evaluated for in vitro antibacterial activity against selected medically important gram-(+) and gram-(-) bacterial species viz. Staphylococcus aureus, Bacillus cereus, Salmonella typhi, Pseudomonas aeruginosa and Escherichia coli, and antifungal activity against few pathogenic fungal species viz. Aspergillus niger, Aspergillus flavus, Trichoderma viride and Curvularia lunata. The cytotoxicity has been determined by measuring IC50 values against human cell lines HeLa, Hep G-2, QG-56 and HCT-116. Among the compounds screened, 3a-3e showed the most potent biological activity against tested bacteria and fungi. Compounds 3a-3e displayed higher cytotoxicity than curcumin. The curcumin derivatives were also evaluated for in vivo anti-inflammatory activity. In contrast, the compounds 6a-6e and 7a-7e showed dramatically decrease in biological activity.