Alkaloids diterpene

Another reported application of inverse-detected 2D NMR was the 1989 elucidation of the structure of the diterpene alkaloid lassiocarpine (11) (Takayama et al. 1989). This study utilized both HMQC to establish one-bond correlations and HMBC to obtain long-range connectivity information to link the structural components elucidated by other means together. 

Connectivities shown on the structure of lassiocarpine (11) above allowed the authors to bridge the quaternary carbons and heteroatom in the structure to link structural fragments, allowing the assembly of the hexacyclic ring system. 

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This C2Q pyrophosphate (122), thought to provide the carbon framework of the diterpene alkaloids such as veatchine (123), atisine (124),... 

Mass spectrometry in structural investigation of diterpene alkaloids 97IZV1096. 

The C2o-diterpene alkaloids have long served as classic targets within the field of natural product synthesis [14], Total syntheses of four C2o-diterpene alkaloids have thus far been reported atisine [15], veatchine [16], garryine [17], and napelline [18]. In spite of this progress, synthetic efforts toward the hetisine alkaloids have been relatively sparse. Prior to our work in the area, these efforts include one total synthesis and five synthetic studies. 

Similarly, oxidation with DMD and KMn04 of diterpene alkaloids eldeline, talatizamine, aconitine, and zongorine has been carried out (95). 

Dr. Ken ichi Takeda, then Director of Shionogi Research Laboratories, Na-gata extended his research efforts to include the first total synthesis of the diterpene alkaloid group including atisine, garryine, and veatchine as well as the gibberellins all in their racemic form. 

The benzyne route to 1-cyanobenzocyclobutenes has been employed for the synthesis of a myriad of complex natural products. The cyano group in (74) was used to attach the dienophile as well as for building die imino bridge of (75), an important precursor for some diterpene alkaloids (Scheme 15).110... 

Oxonine 1, a derivative of the diterpene alkaloid aconitine, undergoes smooth oxidation when treated with exactly one equivalent of periodic acid. The product thus obtained, which shows no aldehyde or ketone absorption in the ir spectrum, is converted into 2 when heated in dilute aqueous base with air passing through the solution. 

Uddin MJ, Kokubo S, Ueda K, Suenaga K, Uemura D (2001) Haterumaimides F-I, Four New Cytotoxic Diterpene Alkaloids from an Ascidian Lissoclinum Species. J Nat Prod 64 1169... 

Volume 15 of this series features four important reviews of research on alkaloids. Chapter 1 by B. S. Joshi, S. W. Pelletier and S. K. Srivastava is the first comprehensive review of the carbon-13 and proton NMR shift assignments and physical constants of diterpene alkaloids and their derivatives. In addition to the catalogue of spectral and physical data, the chapter includes a table of the occurrences of these alkaloids in various plant species, tables containing molecular formulas versus calculated high-resolution mass values, and calculated high-resolution mass values versus the molecular formulas of diterpenoid alkaloids, as well as seven tables summarizing the carbon-13 chemical shifts of various functional groups in diterpenoid alkaloids. 

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