Macrocyclic lactam alkaloids

Macrocyclic lactam alkaloids Verbascum phoeniceum SiOj AcOEt + MeOH T + EtOH 254 nm r. Dragendorff s Identification 22... 

Bacterial metabolites include novel alkaloids, peptides, and macrocyclic lactams. The most unusual metabolites from dmoflagellate are polyethers, both linear and macrolides. The latter were also found abundantly in brown seaweeds (Chart 7.6.FA/PO). Filamentous fimgi have afforded new isoindole and quinazoline alkaloids, as well as new-skeleton steroids (Chart 7.6.A/P/I). 

Macrocyclic lactams. Two key steps in a synthesis of the polyamine alkaloid dihydroperiphyUine (4) involve ring expansion of the cyclic imino ether 1 by reaction with the /3-lactam 2 to form 3. Sodium cyanoborohydride in acetic acid reduces 3 in high yield to 4, probably by way of intermediates a and b.2... 

Macrocyclic Lactams.— Two spermidine alkaloids have been prepared by the reaction of spermidine itself with a thiazolidine 2-thione diamide derivative under high-dilution conditions the two regioisomers produced were separated by chromatography.An interesting boron-template cyclization of the amino-ester (173) to the lactam (174) has been used to prepare several members of the celacinnine group of natural products (Scheme 85). ... 

In the course of biogenesis-type syntheses of lupin alkaloids, reduction of protected macrocyclic acyloin 50 (Scheme 15) has been found to be a second route to bicyclic aminoalcohol 14a (69JA7372). Another 11-membered ring compound, namely caprinolactam (51), on anodic oxidation in the presence of halide ions produces 6/7 bicyclic lactam 52 together with two isomeric 5/8 bicyclic lactams (87CJC2770). 

Following the biogenetic classification, we first address macrolactones, divided into the main family groups that have received synthetic attention via RCM (re-sorcinylic, salycilates, other antibiotic macrolides, macrocyclic musks, epothilones, amphidinolides, other polyketides, and natural cyclophanes), then the terpenoids, followed by the macrocycles obtained from the amino acid metabolism (lactams, depsipeptides, alkaloids), and finally the glycolipids. 

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