Muscarine, oxazole, thiazole, imidazole, and peptide alkaloids, and other miscellaneous alkaloids

Muscarine, oxazole, imidazole, thiazole, and peptide alkaloids and other miscellaneous alkaloids

“…The synthesis of podocarpamide (49), starting with the condensation of piperonal with malonic acid, has confirmed the identity of the alkaloid isolated from Zanthoxylum podocarpum bark.38 A synthesis of tunichromes Mm-1 (50; R = COCH,NH,) and tunichrome Mm-2 [50; R = COCH(Bu')NH,] which are unstable polyphenolic blood pigments of the iron assimulating tunicate Molgula manhattensis has been achieved by a more versatile route39 compared to a previously reported synthesis of the related pigment An-L409 22 Meanwhile a total synthesis of the antibiotic (-)-hygromycin A confirms its unusual aminocyclitol structure ( 5 1).41 Starting from D-glucose the aminocyclitol moiety (52) was prepared (Scheme 3) from the known 5-enopyranoside (53) by Ferrier rearrangement giving the cyclohexanone (54) which was dehydrated in situ to the enone (55). Subsequent reduction and protection of the enol gave (56) which by mesylation and azidolysis produced (57).…”

Muscarine, oxazole, imidazole, thiazole, and peptide alkaloids, and other miscellaneous alkaloids

“…22 Ulosantoin is a potent insecticide isolated from the sponge Ulosa ruetzleri. This phosphonylated hydantoin (48) was identified by X-ray crystallographic studies. A related compound, the creatine (49), was also obtained from this sponge.…”

Muscarine, imidazole, oxazole, thiazole and peptide alkaloids, and other miscellaneous alkaloids

“…16 The structure of this catechol-oxazoline-hydroxamic acid containing metabolite was determined by FAB-MS, 1 H and 13 C NMR spectroscopy. A related siderophore is anguibactin 17 which has a thiazole ring instead of oxazoline.…”