Labdane alkaloids

Uddin J, Ueda K, Siwu ERO, Kita M, Uemura D (2006) Cytotoxic Labdane Alkaloids from an Ascidian Lissoclinum sp. Isolation, Structure Elucidation, and Structure-Activity Relationship. Bioorg Med Chem 14 6954... 

Uddin, J., Ueda, K, Siwu, E.R.O., Kita, M., and Uemura, D. (2006) Cytotoxic labdane alkaloids from an ascidian Lissoclinum sp. isolation, structure elucidation, and structure-activity relationship. Bioorg. Med. Chem., 14, 6954—6961. 

Some useful reviews of diterpenoid chemistry have appeared. During the year the n.m.r. resonances of a number of groups of diterpenoids have been assigned. These include the labdanes, podocarpanes, kauranoids, beyeranes, gibberellins, and aconitine alkaloids.In addition n.m.r. has played a major role in the elucidation of the structure of many new diterpenoids during the year and this is discussed in the relevant sections. 

Correlations within a stereochemically homogeneous series of compounds, such as monosaccharides and steroids, which are well documented elsewhere in the literature are considered in outline only. Series of compounds which are essentially dimeric or polymeric types built up from chiral monomeric units are not covered in detail, since their configurations follow readily from those of the monomeric unit. Examples of such polymeric-type compounds are di-, oligo- and polysaccharides bis (benzylisoquinoline) and other dimeric alkaloids biflavonoids and polypeptides. Series of natural products having essentially the same carbon skeleton but known in a variety of stereochemical types due to epimerism at one or more chiral centres are frequently covered by general notes rather than by large numbers of examples. This treatment is given, for example, to the labdane-type diterpenes and the yohimbane-type alkaloids. 

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