5436-21-5Relevant articles and documents
Biosynthesis of polyketide-terpenoid (Meroterpenoid) metabolites andibenin B and andilesin A in aspergillus variecolor
Simpson, Thomas J.,Anmed, Salman A.,McIntyre, C. Rupert,Scott, Fiona E.,Sadler, Ian H.
, p. 4013 - 4034 (1997)
Incorporation of 13C-labelled acetates and nethionine indicate that andibenin B (1) and andilesin A (5), C25 metabolites of Aspergillus variecolor, are biosynthesised via a mixed polyketide-terpenoid pathway, 18O-Labelling studies, and incorporation of aromatic precursors and mevalonic acids variously labelled with 13C, 2H and 18O provide evidence for the extensive oxidative and other modifications involved in the elaboration of the highly oxygenated polycyclic structures found in these metabolites. The biosynthetic interrelationships among these and other complex meroterpenoid metabolites are discussed.
Electronic Asymmetry of an Annelated Pyridyl-Mesoionic Carbene Scaffold: Application in Pd(II)-Catalyzed Wacker-Type Oxidation of Olefins
Bera, Jitendra K.,Dutta, Indranil,Kunnikuruvan, Sooraj,Reshi, Noor U Din,Saha, Sayantani,Yadav, Suman
, p. 11385 - 11393 (2020/11/23)
The two donor modules of an annelated pyridyl-mesoionic carbene ligand (aPmic) have different σ- and π-bonding characteristics leading to its electronic asymmetry. A Pd(II) complex 1 featuring aPmic catalyzes the oxidation of a wide range of terminal olefins to the corresponding methyl ketones in good to excellent yields in acetonitrile. The catalytic reaction is proposed to proceed via syn-peroxypalladation and a subsequent rate-limiting 1,2-hydride shift, which is supported by kinetic studies. The electronic asymmetry of aPmic renders a well-defined coordination sphere at Pd. The favored arrangement of reactants on the metal center features an olefin trans to the pyridyl module and a tbutylperoxide trans to the carbene. This arrangement gains added stability by the π-delocalization paved by the compatible orbitals on Pd, the pyridyl module, and the olefin that is perpendicular to the Pd(aPmic) plane. The π-interactions are absent in an alternate arrangement wherein the olefin is trans to the carbene. Density functional theory studies reveal the matching orbital overlaps responsible for the preferred arrangement over the other. This work provides an orbital description for the electronic asymmetry of aPmic.
New process for preparing pyrazole carboxylic acid derivatives
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Paragraph 0047; 0065-0070, (2017/04/03)
The present invention relates to a method for preparing a pyrazole carboxylic acid derivative. More particularly, the present invention relates to a novel method for preparing 1-alkyl-3-haloalkyl pyrazole-4-carboxylic acid represented by chemical formula (I) and useful for an intermediate for the preparation of a pyrazole carboxanilide-based sterilizing agent. In chemical formula (I), R_1 represents a C1-C3 lower alkyl group, R_2 represents any one of CHF_2, CF_3, CHCl_2 and CCl_2.COPYRIGHT KIPO 2017