Natural Products Chemistry, Band 3

acetate acid Acta activity addition afforded alkaloids Antibiot assigned base Biochem biosynthesis Bull carbon Chem chemical Chemistry chiral Commun compounds confirmed containing converted COOEt COOH COOME coupling cyclization derivative determined double bond established ester followed formation formed gave give H OH H-nmr hydrogen hydrolysis incorporated indicated intermediate involving isolated isomer Jones Jones oxidation Lett MeOH method methyl mixture moiety Nakanishi NaOH natural obtained occurs OCH3 OH H OH OH OMe OMe OTHP oxidation Phytochemistry plants position prepared presence proton R₁ R₂ reaction rearrangement reduction Remarks ring Route separated shift shown shows signals skeleton spectrum step stereochemistry structure studies suggested synthesis Tetr Tetrahedron treatment University various x-ray analysis yield он он он