Bisindoles structures

In addition to monomeric compounds, Tabemaemontana plants contain many bisindole alkaloids that are classified on the basis of constituent monomeric units, as in the extensive review by Cordell and Saxton in Volume XX of this series (14). This classification is more rational and comprehensive than others (I, 13, 15) and will be used as a guide for the representation of structural formulas and for the discussion of the chemistry of single alkaloids. 

The great number of different alkaloids found in Tabemaemontana precludes a discussion of the structure elucidation and chemistry of all of them. To keep the treatment concise, a major compromise was necessary. The alkaloids that have been reported in previous volumes of this treatise (as indicated in Table I) and their trivial modification will not be mentioned here. This compromise eliminates from the discussion well-established and long-known alkaloids that were isolated not only from Tabemaemontana but also from other genera. Moreover, the plumeran alkaloids isolated up to 1976 and ebuman-type and bisindole alkaloids isolated up to 1979 are covered in Volumes XVII and XX. The main efforts of this chapter will be focused on more recently isolated compounds, some of which are structurally and biogenetically relevant and have been found only in plants of the genus Tabemaemontana. 

Ervafoline did not fragment under the acidic conditons used for the cleavage of other bisindole alkaloids. The complete structure and relative stereochemistry of ervafoline, as shown in formula 246, were determined by a single-crystal X-ray study. 

The same authors then studied the formation of ternary complexes with cahnoduhn, TFP and two bisindole drug molecules vinblastine and KAR-2 (structures shown in Figure 6.25) using the near-UV CD method. They found that both TFP and KAR-2 are able to bind to calmodulin simultaneously forming a ternary species but that vinblastine is not able to bind to a TFPiCaM complex. If the CD experiment was repeated under conditions in which the... 

ISOLATION, STRUCTURE ELUCIDATION, AND BIOSYNTHESIS OF THE BISINDOLE ALKALOIDS OF CATHARANTHUS... 

The occurrence of structurally established bisindole alkaloids in Cath-aranthus roseus (L.) G. Don and in the minor species of Catharanthus, namely, C. lanceus (Boj. ex DC.) Pich., C. longifolius Pich., C. ovalis Mgf., C. pusillus (Murr.) G. Don, and C. trichophyllus (Bak.) Pich, is... 

Bisindole Alkaloids with Established Structures Isolated from Catharanthus Species... 

Since the last major review of the biosynthesis of the monoterpenoid indole alkaloids (97), there have been several full and partial 98-104) reviews of various aspects of the work that has been conducted since 1974. Two major developments have dominated the field in this period, namely, the demonstrations that (i) strictosidine (33) is the universal precursor of the monoterpenoid indole alkaloids and (ii) selected cell-free systems of C. roseus have the ability to produce the full range of alkaloid structure types, including the bisindoles. This section traces some aspects of these developments, paying particular attention to work been carried out with C. roseus, and omitting work, important though it may be, on other monoterpenoid indole alkaloid-producing plants, e.g., Rauwolfia, Campto-theca, and Cinchona. 

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