Acutumine alkaloids

The acutumine alkaloids are another class of alkaloids present only in the family Menispermaceae. Of the nine citations on the iho ature, only five are for different alkaloids. In these alkaloids rings C and D are like dwse in the hasubanane alkaloids, but they also derive from the benzyh rahydroisoquinoline nucleus, as the great majority of alkaloids present in plants of this family. Figure 3 shows the five different acutumine alkaloids described in the literature and Scheme 16 presents a possible biogenetic pathway. 

Sinoacutine and pallidine are found in Corydalis incisa (Pers.) (Fumariaceae)/ and the former alkaloid is also found in Stephania glabra (Menispermaceae). The chlorine-containing alkaloids acutumine and acutumidine are present in Menispermum canadense L. (Menispermaceae), and a full paper describing the isolation and structural elucidation of these two bases has been published. Hernandine (194) and hernandifoline (195) have been obtained from Stephania hernandifolia. 

Alkaloids of the types Bis-BIQ, PROAPO, APORPHIN, PROTOB and MORPHIN are present in the sub-tribe Cocculineae, and also in almost all of the genera of the family Menispermaceae so far investigated. However, there are two types of alkaloids which seem to differentiate chemically the sub-tribe Cocculineae from the others. They are the acutumine type present in Menispermum, Sinomenium and Limacia, and the isooxoaporphines present in Menispermum and Sinomenium. 

Total Synthesis of (-)-Acutumine Castle and co-workers reported on the first total synthesis of (—)-acu-tumine 147 in 2009. " Isolated from Sinomenium acutum by Goto and Sudzuki in 1929, " this tetracyclic alkaloid is noted for its unique structural features that include a spiro-cyclic propellane-type system. This molecule also offers useful biological activities such as selective T-cell cytotoxicity and anti-amnesic properties. The synthetic route started from easily synthesizable starting materials chiral 143 and 144 to generate the precursor 145. The key step of the synthesis involves a one-pot ozonolysis-reductive amination on 145 to afford 146 (Scheme 39.43). 

---