نتایج جستجو برای: αα bis substituted benzylidene cycloalkanones
تعداد نتایج: 86685 فیلتر نتایج به سال:
Over the years secondary metabolites have been considered as lead molecules both in their natural form and templates for medicinal chemistry. Some such polyphenols flavan-3-ols exert beneficial effects after a modification by microbiota. Synthetic precursors of some these modified compounds, turn, carried ?-alkylidenebutenolide moiety which characterizes large class bioactive products endowed w...
Uncatalysed 1,3-dipolar cycloaddition reactions between two phosphaalkynes, P≡CR (R = Bu(t) or Me), and a series of di-, tri- and poly-azido precursor compounds have given very high yields of a range of triazaphosphole substituted systems. These comprise the 1,1'-bis(triazaphosphole)ferrocenes, [Fe{C5H4(N3PCR)}2], the tris(triazaphosphole)cyclohexane, cis-1,3,5-C6H9(N3PCBu(t))3, and the poly(al...
Type I and II topoisomerase activities were partially purified from Pneumocystis carinii. The catalytic (strand-passing) activities of both enzymes were selectively inhibited by members of a series of dicationic-substituted bis-benzimidazoles compared with those of topoisomerases of mammalian (calf thymus) origin. The most active inhibitors of the parasite enzymes were also highly effective in ...
Alpha thalassemia is a genetic disease characterized by insufficient expression or definite absence of the α-globin chain. Three large deletions (thal-1; 26.5 kb MedII, 20.5 and 17.4 MedI) two small (thal-2; 4.2 3.7 kb) have been in our country. In addition, different PolyA mutations (PA1: AATAAA>AATAAG PA2: AATAAA>AATGA) on α2-globin gene (αα/αPAα), 5nt deletion (αα/α5ntα), unstable Hb v...
Supramolecular polymers are linear chains of low molar mass monomers held together by reversible and directional non-covalent interactions, which can form gels or highly viscous solutions if the self-assembled chains are sufficiently long and rigid. The viscosity of these solutions can be controlled by adding monofunctional compounds, which interact with the chain extremities: chain stoppers. W...
Internal bis-substituted propargylic diols were subjected to enzymatic kinetic resolution promoted by CAL-B. Employing a two round sequence EKR, mono- and bis-acetoxy propargylic products were obtained in a high enantiomeric ratio (E > 200). The efficiently resolved chiral 8b was applied in a concise synthesis of (S)-1b, an optically active natural product produced by fungi Clitocybe catinus.
Catalytic enantioselective multicomponent processes involving bis(pinacolato)diboron [B2(pin)2], 1,3-enynes, and aldehydes are disclosed; the resulting compounds contain a primary C-B(pin) bond, as well as alkyne- and hydroxyl-substituted tertiary carbon stereogenic centers. A critical feature is the initial enantioselective Cu-B(pin) addition to an alkyne-substituted terminal alkene. This and ...
Stable, water-soluble aminosugar staurosporine, K-252a and rebeccamycin analogs have been prepared by nucleophilic opening of C(2)-symmetric N-activated bis-aziridines by bis-indolylmaleimides. This divergent strategy allows the synthesis of unsymmetrical substituted derivatives and provides an easy access to the piperidine and pyrrolidine analogs.
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