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A series of novel 3,4-dihydropyrimidin-2(1H)-ones bearing urea, thiourea, and sulfonylurea moieties were synthesized and pharmacologically evaluated as vasodilator agents. The most interesting vasodilators were the thiourea derivatives 6a and 6b and the urea derivatives 6f-6i and 7f-7h, although the ureas were relatively more active than thioureas. Twenty-fold more active than diazoxide, the urea 6g was the most potent vasodilator ([EC.sub.50] = 0.983 [+ or -] 0.061 [micro]mol/L) and proved to act as a voltage-gated calcium channel blocker. The lack of activity of sulfonylureas, 6k and 7j, could be attributed to their partial ionization at the physiological pH because of their acidic character. It should be interesting to investigate a larger number of compounds, including N-methylated sulfonylureas, to increase the vasodilator activity and to explore other biological models. Key words: 3,4-dihydropyrimidin-2(1H)-ones, voltage-gated calcium channel blockers, vasodilator activity, urea, thiourea, sulfonylurea. Nous avons synthesis une serie de nouvelles 3,4-dihydropyrimidin-2(1H)-ones portant des groupes uree, thiouree et sulfonyluree et avons evalue leur activite pharmacologique en tant qu'agents vasodilatateurs. Les vasodilatateurs les plus interessants etaient les derives de thiouree 6a et 6b et les derives d'uree 6f-6i et 7f-7h, les urees ayant ete relativement plus actives que les thiourees. L'uree 6g, 20 fois plus active que le diazoxyde, a montre l'activite vasodilatatrice la plus elevee ([EC.sub.50] = 0,983 [+ or -] 0,061 [micro]mol/L) et un mode d'action par blocage des canaux calciques sensible a la tension. L'absence d'activite des sulfonylurees 6k et 7j pourrait s'expliquer par leur caractere acide entrainant une ionisation partielle a pH physiologique. Il pourrait etre interessant d'etudier un plus grand nombre de composes, dont des sulfonylurees N-methylees, en vue d'augmenter l'activite vasodilatatrice et d'explorer d'autres modeles biologiques. [Traduit par la Redaction] Mots-cles: 3,4-dihydropyrimidin-2(1H)-ones, bloqueurs de canaux calciques sensibles a la tension, activite vasodilatatrice, uree, thiouree, sulfonyluree., Introduction Voltage-gated calcium channel blockers belong to a large class of drugs used in the treatment of cardiovascular diseases such as arterial hypertension, angina pectoris, and cardiac arrhythmias. (1) Such [...]

Polypropylene (PP) is a strong, tough, crystalline thermoplastic material with high performance. Because of its diverse thermo-physical and mechanical properties, it is utilized in a wide variety of disciplines. In this study, the impact of free quenching on the thermo-physical characteristics of PP/calcium carbonate (CaCO3) composites was examined. Three distinct heating procedures were used. First, composites were cooled from their melting phase temperature to ambient temperature. Second, composites were cooled from 130°C to a pre-determined and controlled temperature (T: 0°, 20°, 30°, 40°, 50°, 60°, 70°, 80°C). Third, composites were temperature-tested using annealing. The findings suggest that the elongation-at-break and impact strength may be improved following an initial quenching process from the melting phase to ambient temperature. On the other hand, a second quenching process at 0°C produces superior results, and a correlation between mechanical and thermal characteristics is noted; however, while these qualities are increased, others, such as flexibility, density, Vicat softening temperature (VST), and heat distortion temperature (HDT) are negatively impacted. [ABSTRACT FROM AUTHOR]

A green method for synthesizing 1,4-dihydropyridines (1a-j) by a one-pot reaction of various aldehydes, ethyl acetoacetate, and ammonium carbonate, catalyzed by a seashell and kaolin powders, mixed and calcined at 500 and 800 °C, under solvent-free conditions, has been developed. The catalyst was characterized by physicochemical techniques, namely, X-ray diffraction (XRD), electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The mixture composed of 20% seashell and 80% Kaolin (Q3-500), calcined at 500 °C, gave the best results (78 to 96% yields). Q3-500 separation from the reacting medium was carried out by filtration and reused several times with a slight decrease in yields. Compared with other conventional methods, the present method is inexpensive and offers advantages, namely: the catalyst is eco-friendly, recyclable, and gives high yields with shorter reaction time. A seashell/Kaolin calcined system (20/80) at 500°C was elaborated to catalyze the Hantzsch reaction under solvent-free conditions. Using Q3-500 six times gave dihydropyridines with excellent yields with a slight loss of activity. The improvement of the catalytic properties of the kaolin surface is due to the increase of cationic content. [ABSTRACT FROM AUTHOR]

Five perovskite materials of the general formula La1–xSrxMn1-yZnyO3 (x = 0, 1, 2, 3, and y = 0, 2) were successfully synthesized by the citric acid sol-gel route and characterized by scanning electronic microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Brunner-Emmet-Teller (BET) technique and X-ray photoelectron spectroscopy (XPS). The materials were employed as heterogeneous catalysts in the Hantzsch reaction, producing 1,4-dihydropyridine derivatives. Incorporating Zn into the parent perovskite LaMnO3 improved the catalytic activity, which was greatly enhanced by the simultaneous introduction of Sr. In addition to the positive effect of Zn and Sr incorporation, the results also showed that the catalytic activity was related to the surface Mn4+ content and acidic character. The La0.9Sr0.1Mn0.8Zn0.2O3 catalyst was recycled and reused four times after demonstrating significant catalytic activity in a polar protic solvent (ethanol). After four cycles of use, the catalyst did not exhibit a significant reduction in catalytic activity, despite the formation of some secondary phases revealed by XRD and XPS analyses. Zn and Sr doubly partial substitution in lanthanum manganite perovskite resulted in a high catalytic activity of the Hantzsch reaction. The results showed that the catalytic activity is related to the creation of oxygen vacancies and the defect associations, in addition to surface acidity and Mn4+ content [ABSTRACT FROM AUTHOR]