This article is an orphan, as no other articles link to it. Please introduce links to this page from related articles. (October 2022)

Chlorotonil A

Names
IUPAC name (1S,2R,3Z,5E,7S,10S,14R,15R,16S,20S)-12,12-dichloro-2,7,10,16,18-pentamethyl-8-oxatricyclo[12.8.0.015,20]docosa-3,5,17,21-tetraene-9,11,13-trione
Identifiers
CAS Number	1009813-26-6[1] N
3D model (JSmol)	Interactive image
ChEMBL	ChEMBL4290170
ChemSpider	28284718
PubChem CID	24742044
CompTox Dashboard (EPA)	DTXSID401043833
InChI InChI=1S/C26H32Cl2O4/c1-14-12-16(3)21-19(13-14)10-11-20-15(2)8-6-7-9-17(4)32-25(31)18(5)23(29)26(27,28)24(30)22(20)21/h6-12,15-22H,13H2,1-5H3/b8-6-,9-7+/t15-,16-,17+,18+,19-,20+,21-,22-/m1/s1 Key: RQYZFUUTQJMTMJ-JCSZEPHKSA-N
SMILES C[C@@H]1/C=C\C=C\[C@@H](OC(=O)[C@H](C(=O)C(C(=O)[C@@H]2[C@H]1C=C[C@H]3[C@H]2[C@@H](C=C(C3)C)C)(Cl)Cl)C)C
Properties
Chemical formula	C26H32Cl2O4
Molar mass	479.436 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

Chlorotonil A is a polyketide natural product produced by the myxobacterium Sorangium cellulosum So ce1525.^[2] It displays antimalarial activity in an animal model,^[3] and has in vitro antibacterial and antifungal activity.^{[citation needed]} The activity of chlorotonil A has been attributed to the gem-dichloro-1,3-dione moiety, which is a unique functionality in polyketides. In addition to its unique halogenation, the structure of chlorotonil A has also garnered interest due to its similarity to anthracimycin, a polyketide natural product with antibiotic activity against Gram-positive bacteria. Recently, structure-optimization resulted in semi-synthetic derivatives ChB1-Epo2 and Dehalogenil, molecules with significantly improved physicochemical properties.^[4][5]

Chlorotonil A is synthesized from a type I modular polyketide synthase (PKS). This gene cluster does not have any acyltransferase (AT) domains, indicating that it is a trans-AT PKS; in these systems, there is a tandem-AT domain that loads the extender subunits onto the acyl carrier protein (ACP) and checks the intermediates, rather than individual AT domains in each module. The gene cluster of chlorotonil A is organized so that the initiator, acetyl-CoA, is loaded onto the tandem-AT domain, then is iteratively elongated with malonyl-CoA units to construct the macrolactone backbone. At modules 3 and 7, a double bond shift occurs in the elongation module to allow for the β,γ-unsaturation and α-methylation. There is a spontaneous, non-enzymatic intramolecular Diels-Alder-like [4+2] cycloaddition at module 8 to furnish the decalin motif.

Following macrolactonization by the thioesterase domain of module 10, the premature chlorotonil A core is chlorinated twice by CtoA, a flavin-dependent halogenase. The halogenated core is then methylated by the standalone SAM-dependent methyltransferase CtoF to yield chlorotonil A.^[6]

• Myxobacteria