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.
CuII-Catalyzed Oxidative Formation of 5-Alkynyltriazoles
Liu, Peiye,Brassard, Christopher J.,Lee, Justin P.,Zhu, Lei
supporting information, p. 380 - 390 (2020/01/24)
In an alcoholic solvent under the catalysis of Cu(OAc)2?H2O, organic azide and terminal alkyne could oxidatively couple to afford 5-alkynyl-1,2,3-triazole (alkynyltriazole) at room temperature under an atmosphere of O2 in a few hours. The involvement of 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) is essential, without which the redox neutral coupling instead proceeds to produce 5-H-1,2,3-triazole (protiotriazole) as the major product. Therefore, DBN switches the redox neutral coupling between terminal alkyne and organic azide, the copper-catalyzed “click” reaction to afford protiotriazole, to an oxidation reaction that results in alkynyltriazole. The organic base DBN is effective in accelerating the copper(II)-catalyzed oxidation of terminal alkyne or copper(I) acetylide, which is intercepted by an organic azide to produce alkynyltriazole. The proposed mechanistic model suggests that the selectivity between alkynyl- and protiotriazole, and other acetylide or triazolide oxidation products is determined by the competition between copper(I)-catalyzed redox neutral cycloaddition and copper(II)/O2-mediated acetylide oxidation after the formation of copper(I) acetylide.
Tropylium salts as efficient organic Lewis acid catalysts for acetalization and transacetalization reactions in batch and flow
Lyons,Crocker,Enders,Nguyen
supporting information, p. 3993 - 3996 (2017/09/08)
Acetalization reactions play significant roles in the synthetically important masking chemistry of carbonyl compounds. Herein we demonstrate for the first time that tropylium salts can act as organic Lewis acid catalysts to facilitate acetalization and transacetalization reactions of a wide range of aldehyde substrates. This metal-free method works efficiently in both batch and flow conditions, prompting further future applications of tropylium organocatalysts in green synthesis.