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Abstract: An AE azabicyclic fragment, with a β-hydroxyl group at C-5 and a substituent at C-1, of the C19-diterpenoid alkaloids, was synthesized. The key reactions include an intramolecular Claisen-type condensation, double Mannich reaction, and stereoselective nucleophilic addition of carbonyl group with the assistance of steric effect of 1β-substituent. [Copyright &y& Elsevier]

Three new C-diterpenoid alkaloids, along with twenty-two known alkaloids, were isolated from the whole herbs of Delphinium tatsienense. The new alkaloids include a vakognavine-type C-diterpenoid alkaloid, designated as tatsienenseine A (), and two hetisine-type C-diterpenoid alkaloids, designated as tatsienenseines B () and C (). Their structures were elucidated by IR, HR-ESI-MS, 1D- and 2D-NMR analyses. [ABSTRACT FROM AUTHOR]

Three new diterpenoid alkaloids, along with eleven known alkaloids, were isolated from the whole herbs of Delphinium yunnanense. The new alkaloids include a rearranged-type C-diterpenoid alkaloid, named yunnanenseine A (), and two hetisine-type C-diterpenoid alkaloids, named yunnanenseine B and C ( and , resp.). Their structures were elucidated by detailed NMR-spectroscopic studies. [ABSTRACT FROM AUTHOR]

Three new C19-diterpenoid alkaloids, umbrosumines A-C (1-3), and 11 known compounds (4-14) were isolated from the roots of Delphinium umbrosum. Their structures were elucidated on the basis of the spectroscopic data interpretation. [ABSTRACT FROM AUTHOR]

Two new C 19 -diterpenoid alkaloids, kongboentine A ( 1 ) and kongboentine B ( 3 ), were isolated from the roots of Aconitum kongboense Lauener and their structures were elucidated by spectral data. [ABSTRACT FROM AUTHOR]

Abstract: An tricyclic AEF fragment of C19-diterpenoid alkaloid bearing an angular methyl group and the oxygen function groups at C-1 and C-6 was successfully synthesized. The synthesis features a stereoselective intramolecular Diels–Alder reaction and a highly efficient intramolecular Mannich reaction as well as efficient functional groups transformations. [Copyright &y& Elsevier]

Further investigation on the roots of Aconitum piepunense led to the isolation of a novel bis-diterpenoid alkaloid designated as piepunine (). Its structure was established by extensive interpretation of its 1D- and 2D-NMR data, high-resolution ESI-MS, and IR spectra. Piepunine represents the first example of an atisine-denudatine-type bis-diterpenoid alkaloids. [ABSTRACT FROM AUTHOR]

A new franchetine-type (leueandine 1 ) and two new lycoctonine-type [potanisines F ( 3 ) and G ( 5 )] C 19 -diterpenoid alkaloids have been isolated from the roots of Aconitum hemsleyanum var. leueanthus and Delphinium potaninii , respectively, and their structures were established on the basis of spectral data. [ABSTRACT FROM AUTHOR]

Abstract: A concise strategy for construction of B/C/D ring system of C19-diterpenoid alkaloids was described, which features a highly diastereoselective intramolecular Diels–Alder reaction of masked o-benzoquinone and an efficient Wagner–Meerwein 1,2-shift rearrangement. The functional group transformations of rearrangement product 19 demonstrate a potential for stereoselective installation of oxygen functions on D-ring of many type of C19-diterpenoid alkaloids. [Copyright &y& Elsevier]