4 -Pandamine-type cyclopeptide alkaloids

Mass spectra of 4(14)-Pandamine-type cyclopeptide alkaloids contain all the fragments previously described and in addition fragments b", f and i (Fig. 5, Table 6). These last fragments are related to... 

Fig. 5. Special fragments of 4(14)-pandamine-type alkaloids Table 6. m/z Fragments of 4(14)-Pandamine-Type Cyclopeptide Alkaloids...

The main fragmentation pattern of this category follows that of the 4(14)-frangulanine-, -integerrine- and -pandamine-type cyclopeptide alkaloids and exhibits the same a-m and q-v fragments. 

Lotusanine-B displays the following 5(14)-scutianine-A-type fragments e, f, i, m, q, q". In addition, fragments x, x-CO, y, y-CO of 4(14)-frangulanine-, -integerrine- and -pandamine-type cyclopeptide alkaloids appear. Finally fragments n and o, analogues of n and o of 5(14)-amphibine-B-type cyclopeptide alkaloids occur (Fig. 22). 

The total synthesis of sanjoinine-Gl, a 4(14)-pandamine-type cyclopeptide alkaloid, was achieved in 17 overall steps (1.36% overall yield) starting from D-serine (767). A novel synthetic protocol was developed, including highly diastereoselective synthesis of the (5,5)- -phenoxyleucine unit. 

In 1963 a group of Swiss authors (12) isolated zizyphine from Zizyphus oenoplia and recognized isoleucine and proline as components. Two years later Zbiral etal. (13) proposed a complete structure which was later revised (14). Pais et al. (15) in an earlier preliminary report suggested the structure of pandamine which had been isolated from Panda oleosa. This was confirmed in 1966, and the structure of the similarly constituted pandamine was reported (17). Shortly thereafter Tschesche and co-workers (18) reported the structure of an alkaloid of this type scutianine-A from Scutia buxifolia. Since then the number of cyclopeptide alkaloids of known structure has risen to more than sixty, a figure which Klein and Rapoport had envisioned in 1968 (20). The workers at Gif-sur-Yvette and at Bonn have been in the forefront of these researches but others have made important contributions (19-26). 

Common fragments are fragments that give no information about R, R R R and R but confirm the nature of the aminophenol moiety. Furthermore their occurrence is indicative of 4(14) cyclopeptide alkaloids. Fragment u and common fragments with mh 120, 107 and 103 are more frequent for the 4(14)-pandamine types. 

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