New asymmetrical bispyrrolidinoindoline diketopiperazines from the marine fungus Aspergillus sp. DX4H

Abstract

Known diketopiperazine WIN 64821 and its asymmetric stereoisomers (1-3) had been isolated from the culture broth of a marine gut fungus Aspergillus sp. DX4H. The planar and stereochemistry for new compounds were determined by a suite of techniques including mass, NMR and CD spectra together with Marfey's method. Their inhibitory activity against PC3 cell line had been tested.

A new asymmetric diketopiperazine dimer from the sponge‐associated fungus Aspergillus versicolor 16F‐11

“…Compound 1 contained an infrequent low‐frequent proton signal ( δ H 1.83) for 11′‐H and a normal proton signal ( δ H 4.03) for 11‐H ( δ H 4.08 for 2 ). This low‐frequent shifting of α ‐H of amino acid was also found in “compound 1 ” (11‐H, δ H 2.21) in reference 3, possibly resulted by the shielding effect from aromatic ring to nearby proton . As shown in Figure a, 11′‐H was located in the shielding area of the 2,3‐dihydroindole ring, which explained this chemical shift anomaly.…”

“…Therefore, the chirality of C‐3′ was R . Thus, the structure of 1 was established with its absolute configuration, which is an asymmetric diastereomer (at position 11′) of 2 (Xu et al reported other three asymmetric diastereomers of 2 recently [at positions 2, 11, 2′, 3′, and 11′ for “compound 1 ”, at positions 2, 11, 2′, 3′, 11′, and 15′ for “compound 2 ”, and at positions 2, 11, 2′, 3′, 11′, and 15 for “compound 3”]). All the remaining ROESY correlations were consistent with this structure (Figure a).…”

Recent advances in allelopathy for weed control: from knowledge to applications

“…173 Some of the new nitrogen-containing natural products studied in recent years have been synthesized with a similar geometry to glyphosate, for example, diketopiperazines. [174][175][176][177] The mode of action of these compounds was confirmed to involve interaction with the TIR1 auxin receptor. 178 Auxin is the plant hormone that controls many aspects of plant growth; it regulates cell division coordination, cell expansion, initiation and the formation of new organs or adaptive responses to environmental stimuli.…”

“…Some of the new nitrogen‐containing natural products studied in recent years have been synthesized with a similar geometry to glyphosate, for example, diketopiperazines . The mode of action of these compounds was confirmed to involve interaction with the TIR1 auxin receptor .…”

Recent Discovery of Heterocyclic Alkaloids from Marine-Derived Aspergillus Species

“…More specifically, compounds 52 and 53 were isolated from an organic extract of the sponge-derived fungal strains A. sp. SF-5280 and A. violaceofuscus, respectively, while compounds 54-56 were from a culture of a fungus residing in marine shrimp that were collected along the coast of Dinghai, China [43][44][45]. Compounds 57 and 58 were also isolated from a culture of the marine sediment-derived fungus A. versicolor HDN08-60, and their structures featured the presence of only a diketopiperazine fragment, but no indole ring.…”