Integerrine

Integerrine Tyre—14-Membered Ring with p-Hydroxystyrylamine Unit and /3-Hydroxyphenyi,alanine... 

Centhiumine k Integerrine l Integerrenine l Integerrissine l Myrianthine-A c Pro — Dimethyl Phe C33H36N404 552 232-233° -254° 58... 

The cyclopeptide alkaloids of the integerrine type differ from those discussed in the previous section in that the /3-hydroxyleucine in the ring... 

The feasibility of structural determination by mass spectrometry was demonstrated with integerrine of which only 5.5 mg was available (34a). 

Aralionine-A (21) is included in Table II in that the benzoyl group is readily cleaved and the resultant debenzoylaralionine-A resembles the integerrine type with glycine as the ring amino acid. Only one alkaloid, adouetine-Z, carries an extended side chain in this group of bases. 

Following the fragmentation schemes which Fehlhaber outlined for the frangulanine and integerrine types it was possible to interpret fragments of other peptide alkaloids into feasible structures thus accelerating the study of these bases (42). 

The structures of the bases of frangulanine and integerrine types, to which the majority of known peptide alkaloids belong, can largely be determined by their mass spectra (42). However, the positions of the... 

Scheme I. Mass spectrometric fragmentation of frangulanine- and integerrine-type alkaloids...

Two brominated linear peptides that are found in the sponge Cliona celata, celenamide A (21 R = CH2CHMe2) and celenamide B (21 R = CHMe2), bear close structural relationships to the cyclic peptides integerrin and lasiodine A that occur in plants.16 A I3C n.m.r. analysis of cyclic peptide alkaloids has been reported and the chemical shifts of most of the carbon atoms in discarines A and B, lasiodines A and B, pandamine, pandaminine, and hymenocardine have been assigned.17... 

A later report described the isolation of still a third polypeptide alkaloid, integerrine, C35H39O4N5 (mp 258°), which on the basis of its mass spectrum was assigned structure XXXV (52). 

Fragmentation of 4(14)-Frangulanine- and -Integerrine-lype Cyclopeptide Alkaloids... 

It has already been mentioned that in 4(14)-frangulanine-type cyclopeptide alkaloids R is the P-OH-Leucine side chain, while in 4(14)-integerrine-type cyclopeptide alkaloids R is the P-OH-Phenyla-lanine side chain. This leads to the generalization shown in Table 5. 

Fig. 2. Main fragments of 4(14)-frangulanine- and -integerrine-type cyclopeptide alkaloids...

Fragment R =P-OH-Leu side chain (Frangulanine-type) R =P-OH-Phe side chain (Integerrine-type)... 

Fragments a, c-e, g-h and k-z are the same as in 4(14)-frangulanine-and -integerrine-type spectra. 

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. 

Scutianene-C and sanjoinenine afford the following 4(14)-frangula-nine-, -integerrine- and -pandamine-type fragments e, f, h, i, 1, m, q, x, y and z. 

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). 

A -Desmethyl-integerrine = 5-P-Indolyl-8- -methyl-valyl-9-phenyl-ph-encyclopeptine... 

Isobutyl-8-A -methyl-isoleucyl-9-phenyl-phencyclopeptine (83) 4(14)-integerrine C30H40N4O4 520... 

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