HCID 70639872, compound → Gambogic acid

HRID 734655Notes

Reaction equation

[CH3:1][C:2]([CH3:46])=[CH:3][CH2:4][CH2:5][C@@:6]1([CH3:45])[O:11][C:10]2[C:12]([CH2:40][CH:41]=[C:42]([CH3:44])[CH3:43])=[C:13]3[O:25][C@@:24]45[C:26]6([CH2:33]/[CH:34]=[C:35](/[C:37]([OH:39])=[O:38])\[CH3:36])[O:29][C:30]([CH3:32])([CH3:31])[CH:23]4[CH2:22][C@H:21]([C:27]6=[O:28])[CH:20]=[C:19]5[C:17](=[O:18])[C:14]3=[C:15]([OH:16])[C:9]=2[CH:8]=[CH:7]1.CC(C)=CCC[C@]1(C)OC2C(CC=C(C)C)=C3O[C@@]45C6(C/C=C(/C(O)=O)\CO)OC(C)(C)C4C[C@H](C6=O)C=C5C(=O)C3=C(O)C=2C=C1>>[CH3:1][C:2]([CH3:46])=[CH:3][CH2:4][CH2:5][C@@:6]1([CH3:45])[O:11][C:10]2[C:12]([CH2:40][CH:41]=[C:42]([CH3:43])[CH3:44])=[C:13]3[O:25][C@@:24]45[C@@:26]6([CH2:33]/[CH:34]=[C:35](\[C:37]([OH:39])=[O:38])/[CH3:36])[O:29][C:30]([CH3:31])([CH3:32])[C@@H:23]4[CH2:22][C@H:21]([C:27]6=[O:28])[CH:20]=[C:19]5[C:17](=[O:18])[C:14]3=[C:15]([OH:16])[C:9]=2[CH:8]=[CH:7]1

Participants

Reactant 2

HCID 70639872HCID 70639872, compound

HCID 102004804HCID 102004804, compound

Product 1

HCID 9852185Gambogic acid

Procedure

Gambogic acid (GA, CAS No. 2752-65-0) which was previously isolated as an inseparable stereomeric mixture of C-2 epimers, were separated into two epimers (gambogic acid and epigambogic acid, referred to as 1 and 2) according to the present invention. In the HPLC analysis, GA presented as one peak (m/z 628) on C18 column (Alltima C18, 5μ, 4.6×250 mm) eluted with CH3CN/0.1% acetic acid (90:10). When the fraction corresponding to the single peak was then subject to C8 column (Alltima C8, 5μ, 4.6×250 mm), eluted with CH3CN/0.1% acetic acid (75:25), two completely separated peaks appear. These two peaks were isolated by HPLC under the same analytical condition with each injection of 20 μL acetone solution of gambogic acid (35 mg/mL), yielding 1 (12 mg) and 2 (10 mg). The two peaks being two C-2 epimers of GA was clearly confirmed by extensive spectroscopic analysis and direct comparison of NMR and HPLC data with those of the known R-epimer. In addition, two similar pairs of C-2 epimeric xanthones were also isolated from this plant by the same method. They were identified to be isogambogic acid, epiisogambogic acid, 30-hydroxygambogic acid, and 30-hydroxyepigambogic acid by extensive spectroscopic and chromatographic analysis including HRMS, 2D NMR, and HPLC techniques. All of these epimers except gambogic acid (R-epimer which had been reported by American scientists using single crystal X-ray diffraction) were isolated and separated for the first time, and 30-hydroxygambogic acid and 30-hydroxyepigambogic acid were previously unknown compounds.

Sources & evidence

ORD record: ord-1c63bbee0a90435a9fbcf0dbacc4d9ef
Source dataset: uspto-grants-2009_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07592367B2

Reaction notes

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