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71.
72.
A simple and efficient synthesis of highly substituted pyrroles was achieved in water medium via multi-component strategy, using amine,DMAD/DEAD as well as phenacyl bromide catalyzed by β-CD.Utilizing this protocol various pyrrole derivatives were synthesized in good to excellent yields. 相似文献
73.
Ratnakar N. Asolkar Ahilya Singh Paul R. Jensen William Aalbersberg Brad K. Carté Klaus-D. Feussner Ramesh Subramani Antonio DiPasquale Arnold L. Rheingold William Fenical 《Tetrahedron》2017,73(16):2234-2241
Six cytotoxic and antimicrobial metabolites of a new bromo-phenazinone class, the marinocyanins A-F (1–6), were isolated together with the known bacterial metabolites 2-bromo-1-hydroxyphenazine (7), lavanducyanin (8, WS-9659A) and its chlorinated analog WS-9659B (9). These metabolites were purified by bioassay-guided fractionation of the extracts of our MAR4 marine actinomycete strains CNS-284 and CNY-960. The structures of the new compounds were determined by detailed spectroscopic methods and marinocyanin A (1) was confirmed by crystallographic methods. The marinocyanins represent the first bromo-phenazinones with an N-isoprenoid substituent in the skeleton. Marinocyanins A-F show strong to weak cytotoxicity against HCT-116 human colon carcinoma and possess modest antimicrobial activities against Staphylococcus aureus and amphotericin-resistant Candida albicans. 相似文献
74.
Rodolfo Nino‐Fong Laurie A. McDuffee Blanca P. Esparza Gonzalez M. Ramesh Kumar Erika F. Merschrod S. Kristin M. Poduska 《Macromolecular bioscience》2013,13(3):348-355
The in vitro viability, osteogenic differentiation, and mineralization of four different equine mesenchymal stem cells (MSCs) from bone marrow, periosteum, muscle, and adipose tissue are compared, when they are cultured with different collagen‐based scaffolds or with fibrin glue. The results indicate that bone marrow cells are the best source of MSCs for osteogenic differentiation, and that an electrochemically aggregated collagen gives the highest cell viability and best osteogenic differentiation among the four kinds of scaffolds studied.
75.
Yb(OTf)3 is an efficient catalyst for the intermolecular imino Diels–Alder reaction of aldimines derived from 2‐azetidinone‐tethered aryl imines and electron‐rich dienophiles to afford the quinoline‐β‐lactams. 相似文献
76.
Konkala Karnakar Katla Ramesh Sabbavarapu Narayana Murthy Yadavalli Venkata Durga Nageswar 《Helvetica chimica acta》2013,96(12):2276-2281
The first example of the stereoselective synthesis of (Z)‐ and (E)‐allyl aryl sulfides and selenides from Baylis? Hillman acetates under neutral conditions in H2O by supramolecular catalysis involving β‐cyclodextrin is reported. β‐Cyclodextrin can be recovered and reused. The reaction is very efficient in providing allyl aryl sulfides and selenides in good‐to‐excellent yields with clean reaction profiles under mild reaction conditions. 相似文献
77.
Theoretical investigation on local electronic structure and stability of the π–π stacking interaction of pyrazinamide (PZA) with armchair (5,5) and zigzag (9,0) single‐walled carbon nanotubes (SWCNTs) is performed using density functional theory (DFT). PZA is physisorbed onto nanotube sidewall through interaction of π orbitals of PZA and SWCNT and the enhanced structural stability of PZA/SWCNT systems is due to weak side‐on rather than the head‐on π‐interactions. The physisorption of PZA onto SWCNT sidewall is thermodynamically favored; as a consequence, it modulates the electronic properties of pristine nanotube in the vicinity of Fermi region and π–π stacked interactions is stronger in (9,0) SWCNT compared to (5,5) SWCNT. The density of states (DOS) analysis show that PZA contributes toward the enhancement of electronic states. Projected DOS and frontier orbital analysis in the vicinity of Fermi level region suggest the electronic states to be contributed from SWCNT rather than PZA. In addition, hybrid DFT calculation which includes the dispersion correction is employed to explain the non‐covalent π–π stacking interaction between PZA and SWCNT. The local density approximation and GGA results are compared with DFT‐D to explain near about accurately the weak nonbonded van der Waals interactions between PZA and SWCNTs. © 2012 Wiley Periodicals, Inc. 相似文献
78.
Ramesh C. Kamboj Dinesh Kumar Rita Arora Surinder Berar Geeta Sharma 《Journal of heterocyclic chemistry》2013,50(Z1):E200-E203
The photo‐irradiation of thienylchromenone resulted in the regioselective cyclization which is exclusively controlled by the nature of solvent used as reaction medium. Compared to nonpolar medium, polar solvent furnished a diverse array of novel angular tetracyclic photoproducts with gem‐dihydro functionality and exocyclic double bonds on the fused pyran ring, which is unprecedented to best of our knowledge. 相似文献
79.
One-pot synthesis of benzimidazole compounds from ortho-phenylenediamine and a variety of aldehydes was developed under mild reaction conditions. All the reactions were carried out in the presence of samarium triflate (10 mol%) in acetonitrile at room temperature. 相似文献
80.
A new series of urea, thiourea, and selenourea derivatives with thiazole moieties were synthesized by the nucleophilic addition reaction of (2-amino-4-(3-chlorophenyl)thiazol-5-yl)(2-chlorophenyl)methanone with various substituted isocyanates/ isothiocyanates/isoselenocynates in acetone having a catalytic amount of sodium hydroxide at room temperature with good yields. All the synthesized compounds were fully characterized by spectroscopic data and screened for their in vitro antioxidant activity using 1,1-diphenylpicrylhydrazyl (DPPH), nitric oxide (NO), and hydrogen peroxide (H2O2) radical scavenging methods. A preliminary study of the structure–activity relationship revealed that the compounds containing selenourea functionality along with halogen group have exhibited potent activity (IC50 ≤ 0.0309 µmol/mL) compared to the standards (IC50 ≤ 0.0814 µmol/mL). Thus the title compounds are a new class of potent antioxidant agents and worthy of further investigation. 相似文献