نتایج جستجو برای: 4h chromenes
تعداد نتایج: 6923 فیلتر نتایج به سال:
An efficient entry to the preparation of elusive 4-unsubstituted-3-iodo-2H-chromenes has been accomplished as result of a catalytic cyclization. Thus, upon exposition of [(3-iodoprop-2-yn-1-yl)oxy]arenes to IPrAuNTf2 (3 mol %), in 1,4-dioxane at 100 °C, the desired heterocyclic motif is readily assembled. This process nicely tolerates a variety of functional groups and, interestingly, it is com...
An efficient chiral squaramide-catalysed enantioselective Michael addition of pyrazolin-5-ones to 3-nitro-2H-chromenes for the synthesis of chiral heterocyclic systems containing both chroman and pyrazolone derivatives has been developed. This reaction afforded the desired products in high to excellent yields (up to 98%) with high enantioselectivities (up to 96%) and excellent diastereoselectiv...
Artemisinin is a sesquiterpene lactone endoperoxide extracted from a traditional Chinese medicinal plant Artemisia annua. Artemisinin-based combination therapies (ACTs) are recommended as the best treatment of malaria by the World Health Organization (WHO). Both the phytohormone jasmonic acid (JA) and light promote artemisinin biosynthesis in A. annua. Interestingly, we found that the increase ...
BACKGROUND Pol III-related leukodystrophies, including 4H leukodystrophy, are recently recognized disorders that comprise hypomyelination and various neurologic and non-neurologic clinical manifestations. We report the unique neurologic presentation of the micturition dysfunction in Pol III-related leukodystrophy and describe the novel endocrine abnormalities in this entity. CASE PRESENTATION...
(4h)-1،3- بنزواکسازین-4-اون ها گروه مهمی از هتروسیکل ها هستندکه به علت دارا بودن خواص دارویی و بیولوژیکی گوناگون، بسیار مورد مطالعه و بررسی قرار گرفته و از سنتز و کاربرد آنها بیش از یک قرن می گذرد. اگر چه روش های گوناگونی برای سنتز 4h-1،3- بنزو اکسازین-4-اون ها در منابع گزارش شده است، اما روش های سنتز مشتـقات n- استخلاف شده 1،2-دی هیدرو-(4h)-1،3-بنزواکسازین-4-اون ها بسیار محدود می باشد. آنها ب...
High-efficiency and low-loss processing is the mainstay to reduce cost deepen application of 4H silicon carbide (4H-SiC) wafers in high-power high-frequency electronics. In this study, high-yield slicing 4H-SiC realized by combining femtosecond laser irradiation bandgap-selective photo-electrochemical (PEC) exfoliation. By light-absorption measurements, micro-Raman, micro-photoluminescence char...
A series of new 1,2/1,3-bis[o-(N-methylidenamino-3-aryl-5-phenyl-4H-1,2,4-triazole-4-yl)phenoxy]ethane/propane derivatives 4 were prepared in good yields by treatment of 4-amino-3-aryl-5-phenyl-4H-1,2,4-triazoles 2 with certain bis-aldehydes 1.Compounds 4 were reduced with NaBH(4) to afford the corresponding 1,2/1,3-bis[o-(N-methylamino-3-aryl-5-phenyl-4H-1,2,4-triazole-4-yl)phenoxy]ethane/prop...
4H-1,4-Benzothiazines and its derivatives are potential pharmacologically and industrially useful agents. They were prepared by condensation followed by oxidative cyclization of 2-amino-4,6-dimethylbenzenethiol with varied βdiketones/β-ketoesters in dimethyl sulfoxide. On refluxing with H2O2 in glacial acetic acid, the substituted 4H-1,4Benzothiazines yielded 4H-1,4-Benzothiazine-1,1-dioxides (...
A few imidazolinones [1-aminoethyl/phenyl-2-methyl/phe- nyl-4-acetylidene/benzylidene-imidazolin-5[4H]-ones] were newly synthesized from respetive acetylidene/benzylidene oxazolinones. Schiff's bases were synthesized by the reaction between imidazolinones and benzaldehyde. The antimicrobial screening of almost all compounds showed moderate to significant activities against B. subtilis ATCC 6633...
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