Lamellarin D

Lamellarin D
Names
IUPAC name
3,11-Dihydroxy-14-(4-hydroxy-3-methoxyphenyl)-2,12-dimethoxy-6H-chromeno[4',3':4,5]pyrrolo[2,1-a]isoquinolin-6-one
Identifiers
3D model (JSmol)
ChEMBL
ChemSpider
Properties
C28H21NO8
Molar mass 499.48 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Lamellarins are a group of pyrrole alkaloids first isolated in 1985 from the marine mollusk Lamellaria in the waters of Palau. Over 70 lamellarins and similar compounds were subsequently isolated. Other similar compounds include ningalins, lukianols, polycitones, and storniamides.

Biological activity

These compounds have shown a wide variety of biological activity, including reversal of multidrug resistance, HIV-1 integrase inhibition, and antibiotic activity. Lamellarin D, for example, displays strong cytotoxic activity against tumor cell lines, and is a potent topoisomerase I inhibitor.

Structure

The lamellarins all contain a central pyrrole ring, substituted at the 3 and 4 positions by polyhydroxy- or methoxyphenyls. They are divided into two groups, depending on whether the pyrrole ring is fused or unfused.

Synthesis

The lamellarins have been synthesized by a number of groups, including Isibashi, Steglich, Ruchirawat, Banwell, Alvarez, Gupton, Boger, and Handy.

Steglich synthesis of lamellarin G trimethyl ether

The Steglich synthesis features an oxidative coupling of two benzylic carbons, as well as a Paal-Knorr pyrrole synthesis.

1997 Lamellarin G Trimethyl Ether Synthesis by Steglich: (i) 1. -70 °C, 2 eq. nBuLi; 2. 0.5 eq. I2, -70 °C -> RT (ii) Mol sieves, 12h, RT (iii) EtOAc, 1 eq. Pb(OAc)4, reflux (iv) CH3CN, PPh3, NEt3, Pd(OAc)2

Banwell synthesis of lamellarin K

The Banwell group’s synthesis of lamellarin K includes an intramolecular azomethine ylide cyclization.

1997 - Lamellarin K synthesis by Banwell: (i) nBuLi, THF, -78 °C, 0.83 h; ZnCl2, -78 °C -> 18 °C, 1 h; aryliodide, Pd(PPh3), 18 °C, 4 h (ii) ClCH2CH2Cl, 18 °C, 7 h; Hunig’s base, 83 °C, 32 h (iii) AlCl3, CH2Cl2, 18 °C, 2 h

See also

References

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