Debromomarinone
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Debromomarinone is a chemical compound isolated from marine
actinomycetes The Actinomycetales is an Scientific classification, order of Actinomycetota. A member of the order is often called an actinomycete. Actinomycetales are generally Gram-positive bacteria, gram-positive and anaerobic and have mycelia in a filamento ...
.


Biosynthesis

The proposed biosynthesis of marinone was first reported by Murray ''et al.'' in 2018. The biosynthesis of marinone begins with 1,3,6,8-tetrahydroxynaphthalene (THN), which is known to be biosynthesized via the condensation of five
malonyl-coenzyme A Malonyl-CoA is a coenzyme A derivative of malonic acid. Biosynthesis Malonyl-CoA cannot cross membranes and there is no known malonyl-CoA import mechanism. The biosynthesis therefore takes place locally: * cytosol: Malonyl-CoA is formed by car ...
units followed by the aromatization of the resulting pentaketide using a type III polyketide synthase. Next, THN undergoes geranylation or
farnesylation Prenylation (also known as isoprenylation or lipidation) is the addition of hydrophobic molecules to a protein or a biomolecule. It is usually assumed that prenyl groups (3-methylbut-2-en-1-yl) facilitate attachment to cell membranes, similar to ...
at the C-4 position, yielding 1 (Fig. 1). This transformation is catalyzed in vivo by NphB aromatic prenyltransferase in naphterpin biosynthesis or by CnqP3 or CnqP4 in marinone biosynthesis. Then, 1 undergoes oxidative dearomatization which is catalyzed by VCPO, which is a vanadium-dependent chloroperoxidase enzyme. This transformation yields compound 2. Compound 2 then undergoes two consecutive chlorinations at the C2 position, catalyzed by VCPO, to yield 4. Next, a VCPO catalyzed α-hydroxyketone rearrangement shifts the geranyl substituent from C-4 to C-3, yielding 5. Exposure of 5 to mildly basic conditions induces cyclization to yield the α-chloroepoxide, 6. This is followed by the reductive halogenation of the α-chloroepoxide to yield the hydroxynaphthoquinone, 7. Next, oxidation at the C-2 position and facile E/Z isomerization of the double bond affords the enone, 8, which undergoes a intramolecular hetero-Diels-Alder to yield debromomarinone.


References

{{reflist Benzochromenes Resorcinols 3-Hydroxypropenals within hydroxyquinones Oxygen heterocycles Heterocyclic compounds with 4 rings Tetracyclic compounds