Skimmianine

Skimmianine is a furoquinoline alkaloid found in Skimmia japonica, a flowering plant in family Rutaceae that is native to Japan and China. It is a known acetylcholinesterase inhibitor.^[2]

Skimmianine

Names
Preferred IUPAC name 4,7,8-Trimethoxyfuro[2,3-b]quinoline
Other names Skimmianin; β-Fagarine; Chloroxylonine
Identifiers
CAS Number	83-95-4 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:9172
ChEMBL	ChEMBL21396
ChemSpider	6502
EC Number	110-051-1
KEGG	C10740
PubChem CID	6760
UNII	4E1KLC380B Y
CompTox Dashboard (EPA)	DTXSID90232116
InChI InChI=1S/C14H13NO4/c1-16-10-5-4-8-11(13(10)18-3)15-14-9(6-7-19-14)12(8)17-2/h4-7H,1-3H3 Key: SLSIBLKBHNKZTB-UHFFFAOYSA-N
SMILES COC1=C(C2=C(C=C1)C(=C3C=COC3=N2)OC)OC
Properties
Chemical formula	C14H13NO4
Molar mass	259.261 g·mol−1
Melting point	177 °C (351 °F; 450 K)[1]
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H302, H315, H319
Precautionary statements	P264, P264+P265, P270, P280, P301+P317, P302+P352, P305+P351+P338, P321, P330, P332+P317, P337+P317, P362+P364, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Biosynthesis

The biosynthesis of skimmianine starts from anthranilic acid,^[3] which is very abundant in the family Rutaceae. By combining anthranilic acid acetate, anthraniloyl-CoA is formed as a starting unit and able to extend side chain by adding malonyl-CoA by Claisen condensation. Next, lactam is formed through the cyclization and generate a heterocyclic system, leading the dienol tautomer adopt the 4-hydroxy quinolone tautomer, which is 4-hydroxy-2-quinolone.

With the formation of quinolone, alkylation is happening at C-3 position by introducing dimethylallyl diphosphate. Another key step is the cyclization on the dimethylallyl sidechain, forming a new heterocyclic five-member-ring.^[4] Platydesmine is then forming an intermediate through the oxidative cleavage reaction^[5] by losing an isopropyl group to form dictamine. Finally, skimmianine is formed through the hydroxylation of dictamine.

Biosynthesis of skimmianine