25163-67-1Relevant articles and documents
Enantioselective Ring Opening of meso-Epoxides with Silicon Tetrachloride Catalyzed by Pyridine N-Oxides Fused with the Bicyclo[3.3.1]nonane Framework
Neni?kis, Algirdas,Ston?ius, Sigitas
, p. 6359 - 6369 (2015/10/06)
The synthesis of new chiral Lewis basic organocatalysts that contain pyridine N-oxide moieties fused with the bicyclo[3.3.1]nonane framework is reported. The obtained pyridine N-oxides were employed as catalysts in the enantioselective ring opening of meso-epoxides with silicon tetrachloride. Derivative 1b endowed with two 2,4-diaryl-substituted pyridine N-oxide moieties proved to be a particularly effective catalyst for desymmetrization of norbornene oxide 16i to furnish Wagner-Meerwein rearrangement product 20i in unprecedented 96 % ee. Difunctional congener 3, which is striped of the 4-aryl substituents, exhibited moderate to high levels of asymmetric induction (47-88 % ee) with alicyclic epoxide substrates. Chiral Lewis basic catalysts with pyridine N-oxide moieties fused with a bicyclo[3.3.1]nonane framework were used in the enantioselective ring opening of meso-epoxides. 2,4-Diaryl-substituted N-oxide exhibited excellent asymmetric induction with norbornene oxide (96 % ee), whereas less-substituted congener was most effective with alicyclic epoxide substrates (47-88 % ee).
Synthesis of isobavachalcone and some organometallic derivatives
Grealis, John P.,Mueller-Bunz, Helge,Ortin, Yannick,Casey, Michael,McGlinchey, Michael J.
, p. 332 - 347 (2013/03/13)
Isobavachalcone [2′,4,4′-trihydroxy-3′-(3″-methyl- 2″-butenyl)chalcone, 1] is a prenylated chalcone that has broad biological activity, in particular against neuroblastomas, the most common cancer in infancy. It is currently commercially available at a cost of 190/mg by extraction from Psoralea corylifolia and a number of other African and Asian plants. Several synthetic routes have been explored, and the most efficient procedure involves the palladium-catalysed Stille coupling of 3-iodo-2,4-bis(methoxymethoxy)acetophenone (25) with prenyltributyltin, Claisen-Schmidt condensation with 4-(methoxymethoxy)benzaldehyde to form the triply MOM-protected prenylchalcone 27 and finally deprotection with 2 M HCl in methanol to form isobavachalcone in an overall yield of 15 % over five steps. The X-ray crystal structures of 2,4-dihydroxy-3-iodoacetophenone (21) and of several prenylated chalcones are reported, including the elucidation of their hydrogen-bonding networks in the solid state. The synthetic route has been extended to include organometallic derivatives in which the 4-(methoxymethoxy) benzaldehyde used in the Claisen-Schmidt condensation has been replaced by formylferrocene, formylruthenocene or (η5-formylcyclopentadienyl) (η4-tetraphenylcyclobutadiene)cobalt to form the corresponding analogues of isobavachalcone containing organometallic sandwich moieties.
2'-Substituted chalcone derivatives as inhibitors of interleukin-1 biosynthesis
Batt,Goodman,Jones,Kerr,Mantegna,McAllister,Newton,Nurnberg,Welch,Covington
, p. 1434 - 1442 (2007/10/02)
A series of 2'-substituted chalcone derivatives has been found to show potent inhibition of the production of IL-1β from human peripheral blood monocytes stimulated with lipopolysaccharide (LPS), with IC50 values in the 0.2-5.0-μM range. Some members of the series have also shown inhibition of septic shock induced in mice by injection of LPS, although with low potency. Qualitative structure-activity relationships have shown that the enone is required for activity, which may be mediated by conjugate addition of a biological nucleophile to the chalcone. Electron-poor aromatic rings β to the ketone give enhanced potency. Although electronic effects in the other ring (directly attached to the ketone) are minimal, this ring must possess an ortho substituent for good activity without cytotoxicity, suggesting a degree of selectivity which would not be expected for simple, nonspecific alkylating agents.
