Metabolic products of microorganisms, 256. Pyrrolams, new pyrrolizidinones produced by Streptomyces olivaceus

Abstract

Pyrrolams A to D (1 -4), biosynthetically new pyrrolizidinones produced by Streptomyces olivaceus, have been discovered by chemical screening. Their structures have been determined by spectroscopic methods and by a comparison of (R)-dihydropyrrolam A (5) with a synthetic sample obtained from (S)-proline. The pyrrolams differ from the necine bases found in plant-originating pyrrolizidine alkaloids by their less complicated structures.

Metabolic products of microorganisms. 261. Obscurolides, a novel class of phosphodiesterase inhibitors from streptomyces. I. Production, isolation, structural elucidation and biological activity of obscurolides A1 to A4.

“…Obscurolide A4 (4) [a]£°+42°(c 0.2, MeOH); Rfvalues see Table 1; IR (film) see Table 1; UV Amax (MeOH) nm (s) 205 (16,200), 254 (ll,600), 294 (1,300); XH NMR see Table 2; 13C NMRsee Table 3; EI-MS see Table 1.…”

Enantioselective sp3 C–H alkylation of γ-butyrolactam by a chiral Ir(i) catalyst for the synthesis of 4-substituted γ-amino acids

“…Pyrrolam A 8 has been isolated from the bacterial strain Streptomyces olivaceus along with the related bicyclic lactams pyrrolam B-D. 20 The unique chiral bicyclic lactam with a double bond in the conjugate system has attracted considerable attention of synthetic chemists, and various synthetic strategies have been developed for its total syntheses. Pyrrolam A 8 has been isolated from the bacterial strain Streptomyces olivaceus along with the related bicyclic lactams pyrrolam B-D. 20 The unique chiral bicyclic lactam with a double bond in the conjugate system has attracted considerable attention of synthetic chemists, and various synthetic strategies have been developed for its total syntheses.…”

“…21 Here, we tried to use our originally developed C-H alkylation of g-lactam for the synthesis of dihydro-pyrrolam A 7. 20 The final step to pyrrolam A 8 is a known procedure. The next three steps, which include the removal of the pyridyl group, reduction of the ester moiety, and tosylation of the primary alcohol, were executed without purification of the intermediates.…”

Intramolecular Wittig Reaction: A New Synthesis of (S)‐Pyrrolam A

“…The presence of a C¼C bond in these ring systems is crucial for the observed hepatotoxic, mutagenic, and carcinogenic activities associated with these molecules. Pyrrolam A (1) is a pyrrolizidine alkaloid belonging to the community of naturally occurring pyrrolams, which was isolated in 1993 by the Zeeck group from the bacterial strain, Streptomyces olivaceus along with pyrrolams B -D [4].…”