نتایج جستجو برای: bioactive motif
تعداد نتایج: 74879 فیلتر نتایج به سال:
Ansa-bridged prodiginines are bioactive pigments produced by bacteria. Certain of these structures are reported to be antagonists of protein-protein interactions involved in apoptosis. We describe a new entry to alkaloids of this type, demonstrated with a concise asymmetric synthesis of (+)-roseophilin (3). Our route constructs the pyrrolophane motif via phosphoryl transfer-terminated macroaldo...
Cyclic alkenylsiloxanes were synthesized by semihydrogenation of alkynylsilanes-a reaction previously plagued by poor stereoselectivity. The silanes, which can be synthesized on multigram scale, undergo Hiyama-Denmark coupling to give (Z)-alkenyl polyene motifs found in bioactive natural products. The ring size of the silane is crucial: five-membered cyclic siloxanes also couple under fluoride-...
The gut hormone apelin is a major therapeutic focus for several diseases involving inflammation and aberrant cell growth. We investigated whether apelin-36 contained alternative bioactive peptides associated with normal physiology or disease. Amino acid sequence analysis of apelin-36 identified an amidation motif consistent with the formation of a secondary bioactive peptide (SCNH2). SCNH2 is p...
Class I terpene synthases generate the structural core of bioactive terpenoids. Deciphering structure-function relationships in the reactive closed complex and targeted engineering is hampered by highly dynamic carbocation rearrangements during catalysis. Available crystal structures, however, represent the open, catalytically inactive form or harbor nonproductive substrate analogs. Here, we pr...
Paisley (buta-Jeghe) a motif which has been applied in Iran’s carpets in Islamic era. The history of using this pattern in Iran’s art has always been a controversial issue. Some think of it as a motif belonging to Pre-Islamic decorations such as cedar or pattern of animal wings of the Sassanid era. Meanwhile, others see it as a motif which was imported by one of the cashmere s...
Single-step constructions of molecules with multiple quaternary carbon stereocentres are rare. The spirooxindole structural motif is common to a range of bioactive compounds; however, asymmetric synthesis of this motif is complicated due to the presence of multiple chiral centres. The development of organocatalytic cascade reactions has proven to be valuable for the construction of several chir...
This account highlights some of our recent work on photoinduced trifluoromethylselenolation reactions. research program relies primarily the design a new key shelf-stable selenating reagent that can be involved in various radical processes In particular, we demonstrated arenes, alkenes, alkynes as well aliphatic organic building blocks readily achieved under visible-light irradiation. Mechanist...
Fars is one of the most important areas in kilim rugs and carpet production in Iran. Among the important reasons for variety and multiplicity of kilim rugs in Fars era, is the fact that here Turks and Fars people live together. This article has focused on the motif of Swastika or Broken Cross (Mehraneh in Persian) in these hands-knitted products. This paper aims to study the symbolic language o...
Hunting is a familiar phenomenon for human being, and appearance of “Hunting Motif” on the carpets in Iran, according to the remaining documents, can be dated back to the Safavid era,i.e. the Golden Age of Iranian Carpet. In this period, carpet-weaving elevated to the degree of excellent royal art, and carpet became a luxury, decorative and even commercial commodity. The nature and ...
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