Methanol → HCID 9830867, compound

HRID 2414226Notes

Reaction equation

CO.[CH3:3][C:4]1[C@@H:9]2[CH2:10][C@H:11]([O:36][C:37](/[CH:39]=[CH:40]/[C:41]3[N:45]=[CH:44][N:43]([CH3:46])[CH:42]=3)=[O:38])[C@@:12]3([CH3:35])[O:16][C@@:15]([O:33]C)([C:17]([CH2:19][O:20][C@@H:21]4[O:26][CH2:25][C@@H:24]([OH:27])[C@@H:23]([OH:28])[C@@H:22]4[O:29][C:30]([CH3:32])=[O:31])=[CH:18][C@@H:8]2[C@@H:7]([CH:47]([CH3:49])[CH3:48])[CH2:6][CH:5]=1)[CH:14]=[CH:13]3>>[CH3:3][C:4]1[C@@H:9]2[CH2:10][C@H:11]([O:36][C:37](/[CH:39]=[CH:40]/[C:41]3[N:45]=[CH:44][N:43]([CH3:46])[CH:42]=3)=[O:38])[C@@:12]3([CH3:35])[O:16][C@@:15]([OH:33])([C:17]([CH2:19][O:20][C@@H:21]4[O:26][CH2:25][C@@H:24]([OH:27])[C@@H:23]([OH:28])[C@@H:22]4[O:29][C:30]([CH3:32])=[O:31])=[CH:18][C@@H:8]2[C@@H:7]([CH:47]([CH3:49])[CH3:48])[CH2:6][CH:5]=1)[CH:14]=[CH:13]3

Participants

Reactant 2

HCID 887Methanol

HCID 6918335Eleutherobin3×

Product 1

HCID 9830867HCID 9830867, compound

Procedure

Eleutherobin is an Artifact Derived From Desmethyleleutherobin. Erythropodium caribaeorum was exhaustively extracted with ethanol at room temperature and the ethanol extract was fractionated as described above (and in FIG. 3) for the methanol extract. This procedure yielded only desmethyleleutherobin and the ethylketal analog of eleutherobin which has a C-4 ethoxyl group. Eleutherobin was not detected. This demonstrates that the methyl ketal of C-4 in eleutherobin is an artifact formed by reaction of desmethyleleutherobin with a methanol extraction solvent in the first instance. We have found that desmethyleleutherobin can be converted quantitatively to eleutherobin by treatment with a catalytic amount of pyridinium p-toluenesulfonate in methanol at room temperature. Simply leaving desmethyleleutherobin sitting in methanol without pyridinium p-toluenesulfonate results in no detectable conversion to eleutherobin. However, the initial crude methanol extract of E. caribaeorum has a pH of approximately 4, which is acidic enough to catalyze the conversion of desmethyleleutherobin to eleutherobin during the extraction procedure with methanol or to the ethylketal analog during an extraction procedure with ethanol. Therefore, a preferred extraction procedure for obtaining exclusively desmethyleleutherobin involves freeze-drying freshly collected samples (to reduce water content) and then extracting pulverized dried material multiple times with ethyl acetate. Concentration of combined ethyl acetate extracts in vacuo provides a crude extract that could be purified as described above to give pure desmethyleleutherobin without the formation of eleutherobin.

Sources & evidence

ORD record: ord-b5867ffc5e844f61927f05bca2a92809
Source dataset: uspto-grants-2004_11
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06812037B1

Reaction notes

Loading…