A route for the indirect carbonation of different minerals using (NH 4 ) 2 SO 4 (AS) as a recyclable reagent has been recently proposed. For saving energy, the extraction of alkaline components, such as calcium and magnesium, is typically expected to occur at the roasting stage. To enhance the extraction efficiency, the kinetics and mechanism of the reaction between AS and blast furnace slag (BFS), a Ca/Mg-containing mineral, were investigated in this study. The results showed that the reaction consists of two steps: the decomposition of AS into ammonium bisulfate (ABS) and the reaction between the ABS and the BFS. Isothermal kinetics and equal conversion methods were used to determine the apparent activation energy and reaction-controlling steps in different temperature ranges. The results showed that the decomposition of AS was a chemicalreaction-controlled step with an apparent activation energy of 102 kJ• mol −1 . On the other hand, the reaction between ABS and BFS, which was very quick, was controlled by the ABS supply. During the reaction, a product accumulation layer was generated around the nonreactive BFS particles. However, it was found that ABS can easily pass through this layer and react with the BFS core. The formation of ABS was the limiting step in the roasting process.
New 4-chalcone ursolate and 1-acetyl-3-(4-phenyl)-4,5-dihydro-2-pyrazoline-5-phenyl ursolate derivatives were synthesized by esterification of UA and chalcone or pyrazoline. The compounds were structurally confirmed by IR, 1 H NMR, 13 C NMR, and HR-MS spectroscopy. The cytotoxicity of ten derivatives was evaluated against A549, SKOV3, and HepG2 cell lines by MTT assay. The result showed that several compounds were more potent than UA against A549 and SKOV3 cells; however, none of them were more potent than UA against HepG2.Ursolic acid (UA, 3E-hydroxy-urs-12-en-28-oic acid, 5), a pentacyclic triterpene, has been isolated from a large variety of vegetarian foods and many traditional medicinal plants. In past decades, UA has attracted considerable interest owing to its significant biological activities and promising clinical application as a chemotherapeutic and chemopreventive agent. Indeed, UA exhibits attractive pharmacological properties, including anti-inflammatory activity [1, 2], anti-HIV [3], anti-malarial [4], anti-microbial [5], anti-melanoma [6], and antitumor [7][8][9][10][11].The conjugation of two bioactive compounds is now accepted as an effective strategy for designing ligands, inhibitors, and other drugs [8]. Chalcones, which belong to the flavonoid compounds, exhibit antioxidant and anti-inflammatory properties and have recently attracted attention also for their antitumor activity in preclinical models [12, 13]. The 2-pyrazoline ring system has attracted significant interest in organic and medicinal chemistry over the past several decades. Scaffolds containing the 2-pyrazoline (4,5-dihydropyrazole) heterocycle have demonstrated a wide range of biological activity, including anticancer activity [14]. In order to explore biologically more active derivatives of this naturally occurring triterpene, two series of ursolic acid derivatives were synthesized with chalcone and pyrazoline structures through reactions as shown in Scheme 1. a. NaOH, CH 3 OH, stir, 0-5°C for 0.5 h then room temperature for 18 h; b. N 2 H 4 ·H 2 O, CH 3 COOH, reflux, 2 h; c. (CF 3 CO) 2 O, toluene, stir for 0.5 h, then 3a-3e, reflux, 8 h; d. (CF 3 CO) 2 O, toluene, stir for 0.5 h, then 4a-4e, reflux, 8 h; e. 10% NaOH, acetone, stir, 22 h. 1 2 3a -3e 4a -4e COOR 1 HO 5 c, e d, e 6a -6e 7a -7e 6: R 1 = C O C C R H H N N R H 3 COC 7: R 1 = Scheme 1 2, 3a, 4a, 6a, 7a: R = H; 2, 3b,4b,6b,7b: R = CH 3 ; 2, 3c,4c,6c,7c: R = OCH 3 ; 2, 3d,4d,6d,7d: R = Cl; 2, 3e,4e,6e,7e: R = F
Reactions of natural helicid with a number of 1,3-dicarbonyl compounds or E-ketoester in the presence of ammonium acetate or 1-naphthylamine gave a series of helicid derivatives containing a 1,4-dihydropyridine fragment (2a-2h). Eight novel helicid derivatives were structurally confirmed by IR, 1 H NMR, 13 C NMR, and HR-MS spectroscopy and evaluated for their sedative-hypnotic activities on mice. The results demonstrated that two compounds had higher sedative-hypnotic activity compared with helicid.Helicid (1, 4-formylphenyl-E-D-allopyranoside), is originally isolated from the fruit of Helicia nilagirica Beed [1], a plant indigenous to western China. Owing to a rare allopyranoside, it has a variety of biological activities on the central nervous system such as sedative, hypnotic, and anticonvulsant activities [2]. However, its long onset time and low bioavailability prompted us to search for new derivatives of helicid through structure modifications [3][4][5][6][7].1,4-Dihydropyridines (1,4-DHPs) are among the most widely used drugs for the management of cardiovascular disease [8], which have a broad range of other pharmacological activities, such as antitumor, bronchodilating, antidiabetic, and antiviral [9-12]. 4-Substituted 1,4-dihydropyridines are analogs of NADH coenzymes and an important class of drugs that are potent blockers of calcium (Ca 2+ ) current. A recent computational analysis of the comprehensive medicinal chemistry database found the DHP framework to be among the most prolific chemotypes. From the viewpoint of molecular design, to construct a dual-target drug molecule, a connective molecule can simply be realized by combining two active molecules or their pharmacophores with a linker, while an integrated molecule comes into an entity either by fusing or by merging the common structural or pharmacophoric features of two active molecules, depending on the extent of the common features. This approach facilitates the reduction of molecular size and molecular weight and the optimal overlap between the pharmacodynamic and pharmacokinetic spaces, which will certainly elevate its probability of being a drug. Thus, based on our high throughout work on the structure-activity relationship of helicid, we designed and synthesized eight helicid derivatives containing the DHP framework through the reactions shown in Scheme 1, with the aim to explore new drugs with superior bioactivity and better efficacy [13][14][15]. Pharmacological test showed that compounds 2a and 2h displayed promising sedative-hypnotic activity superior to helicid (Table 1). So, further modification of helicid should be worthwhile.The most common route for the synthesis of 1,4-dihydropyridines is the Hantzsch reaction. It is the condensation of a E-ketoester or 1,3-dicarbonyl compound with an aldehyde and ammonia or primary amine either in acetic acid or by refluxing in alcohol. However, the reaction times for 6-72 h are too long and the yields are generally low. Therefore, in our preliminary study, a series of helicid derivatives 2a-2e w...
The aim of the Symposium was to give an overview of the present status with regard to historical background and to foresee the future trends in the field of photocatalyst research. Serious global and environmental problems have led the ceramics manufacturing industries to closely monitor the formation and accumulation of carbon dioxide and other toxic gases in the atmosphere, the reduction of raw materials, the consumption of energy, and other factors of impact to the industry. Presentations and discussions were carried out on such topics as room-and low-temperature synthesis, low-energy processing, aqueous synthesis and processing, the reuse and recycling of waste materials, and the elimination of such hazardous materials as cadmium, mercury, lead, and six-valence chromium, which are restricted from use on electronic components and automobile parts under the European Committee RoHS guidelines. The ceramic and glass industries have
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