A study of santonins and their derivatives by mass spectrometry

Wasada, Nobuhide; Tsuchiya, Toshikazu; Yoshi, E.; Watanabe, Eiji

doi:10.1016/s0040-4020(01)92561-x

Cited by 15 publications

(10 citation statements)

References 23 publications

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“…The results obtained for the three pairs of 12-hydroxy epimers (27 to 32) are consistent with predictions for only one of these (27,28), while for the other two (29 to 32) they appear anomalous in the sense that the isomers 29 and 32 having the hydroxyl group cis to the hydrogen at the tertiary C-8 exhibit lower values. However, * A further possibility exists in the a-isomer when the hydroxyl and isopropyl groups are axial in a ring C boat conformer.…”

Section: Alcoholssupporting

confidence: 81%

Mass spectrometric studies of diterpenes: VIII—Epimers

Enzell¹,

Wahlberg²,

Gunnarsson³

1974

Org. Mass Spectrom.

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Diterpene epimers differing with respect to orientation of a secondary hydroxyl group, ring fusion or configuration at an asymmetric centre carrying carbon-carbon linked substituents were studied, and certain stereostructural-spectral correlations were achieved for the first two groups. Each of the compounds examined was subjected to multiple scanning at both high and low electron voltage to allow computer assisted statistical calculation and comparison of intensity intervals at a predetermined confidence level for total ion currents and selected peaks.

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Section: Alcoholssupporting

confidence: 81%

Mass spectrometric studies of diterpenes: VIII—Epimers

Enzell¹,

Wahlberg²,

Gunnarsson³

1974

Org. Mass Spectrom.

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“…In contrast, the nmr spectrum of 6 showed a multiplet at 5.42 assigned to the proton at ester-bearing C-8, while the lactone proton signal appeared as a triplet at r 5.97, indicative of attachment at C-6. In accord with this view, acid hydrolysis of 6 gave dihydroelephantolide (13), which was isomeric with 8 and therefore corresponded to the direct hydrolysis product. Accordingly, the signal for the proton at lactone-bearing C-6 in 13 appeared as a triplet at 6.02; the signal for the proton at lactone-bearing C-8 in 8 appeared as a complex multiplet.…”

Section: Table Imentioning

confidence: 68%

“…Accordingly, the signal for the proton at lactone-bearing C-6 in 13 appeared as a triplet at 6.02; the signal for the proton at lactone-bearing C-8 in 8 appeared as a complex multiplet. Furthermore, treatment of dihydroelephantolide (13) with isobutyric anhydride gave a compound shown to be 6 on the basis of comparison of nmr, infrared, and ultraviolet spectra with those of authentic tetrahydroelephantopin (6). Upon treatment of 13 with base under conditions identical with those used during the alkaline hydrolysis of 6, 8 was produced.…”

Section: Table Imentioning

confidence: 99%

“…Brief discussions of the mass spectra of santonin and derivatives13,14 and some sesquiterpene systems15-17 have appeared and a somewhat more extensive treatment of the sesquiterpene widdrol has been presented. [18][19][20] In the course of this study, we have obtained both lowand high-resolution mass spectra of elephantopin (4), tetrahydroelephantopin (6), elephantol methacrylate (11), and dihydroelephantol isobutyrate (12), and low-resolution mass spectra of elephantin (3), elephantol acetate (10), elephantol (5), dihydroelephantol (8), and dihydroelephantolide (13) (Figures 1-11).…”

Section: Table Imentioning

confidence: 99%

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Tumor inhibitors. XL. Isolation and structural elucidation of elephantin and elephantopin, two novel sesquiterpenoid tumor inhibitors from Elephantopus elatus

Sm¹,

Aynehchi²,

Jm³

et al. 1969

J. Org. Chem.

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Evidence is presented for the assignment of structures for elephantin (3) and elephantopin (4), two tumorinhibitory sesquiterpene dilactones isolated from Elephantopus elutus Bertol. Elemental analysis and highresolution mass spectrometry supported a CZOHI~O~ molecular formula for elephantin (3) and a CIBHZOO~ molecular formula for elephantopin (4). Chemical and spectral evidence indicated the presence of cu,&unsaturated lactone, cr,@-unsaturated ester, and epoxide groupings in 3 and 4. Alkaline hydrolysis of 3 gave elephantol (5) and dimethylacrylic acid, while, under the same conditions, 4 gave elephantol (5) and methacrylic acid. Catalytic hydrogenation of elephantol (5) gave tetrahydroelephantol (9). Treatment of elephantol(5) with p-bromobenzoyl chloride gave elephantol p-bromobenzoate (14). X-Ray crystallographic analysis established the structure and stereochemistry of 14 and 5. Hydrogenation of elephantopin (4) gave tetrahydroelephantopin (6). Alkaline hydrolysis of 6 gave dihydroelephantol (8) and isobutyric acid. Acylation of 5 with methacrylic anhydride gave elephantol methacrylate (ll), while acylation of 8 with isobutyric anhydride gave elephantol isobutyrate (12). Acid hydrolysis of 6 gave dihydroelephantolide (13), which on acylation with isobutyric anhydride gave 6. Low-and high-resolution mass spectra of elephantin (3) and elephantopin (4) and a number of derivatives ( 5 , 6 , 8 , 10, 11, 12, and 13) are discussed.Elephantin and elephantopin are cytotoxic sesquiterpene lactones from Elephantopus elatus Bertol., and their isolation and characterization have recently been reported.*s5 It is the purpose of this paper to present in detail the fractionation of the active extract of E. elatus and the isolation and structural elucidation of the active constituents, elephantin and elephantopin! Fractionation of the concentrated ethanol extract (A in Chart I), guided by assay against KB revealed that the active principles were concentrated (Table I) in the chloroform phase (D) of a chloroformwater partition. Partition of this residue between 10% aqueous methanol and petroleum ether concentrated the activity in the aqueous methanol layer (G). Fraction G was chromatographed on a silicic (1) (a) University of Wisconsin. Part XXXIX: 8. M. Kupchan, W.

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“…The loss of C,H,O, (73 mass units) in (-)santonin has been confirmed by high resolution data. 4 Boocock et aZ. 3 invoked a methyl migration to explain this fragmentation process, which later appeared unnecessary.12 It was suggested, however, that the process is triggered by removal of one of the n-electrons from the C,-C, double bond.…”

Section: Unsaturated Keto Lactone (Vii)mentioning

confidence: 99%

Terpenoids—CXXXVII: Fragmentation of constunolide and its derivatives under electron‐impact

Sathe¹,

Kulkarni²,

Kelkar³

et al. 1969

Org. Mass Spectrom.

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Abstract-An attempt has been made to correlate the fragmentation modes and structure of costunolide and some lactones derived from it, containing a ten-membered carbocyclic system. The possible origins for the major fragments have been determined, using high resolution mass spectrometry and deuterium labelling.MASS spectra of aliphatic lactones,lr2 (-)santonin and its derivative^^,^ have been recently investigated. However, the behaviour under electron-impact of sesquiterpenic y-lactones, with a ten-membered carbocyclic system, does not seem to have received much attention. Costunolide is the parent lactone of such a group and the present communication deals with the fragmentation of some of its derivatives. From costunolide (I), the lactones (11): (III),t (IV),t (V)5 and (VI)6 were prepared by known procedures.A comparative study of the mass spectra of lactones I to IV, has revealed some common fragmentation modes and a few significant differences of diagnostic value in structure elucidation. The thermal rearrangement' of I1 and the transannular acid catalysed c y c l i z a t i~n~~~ of I and TI are known. In order to explain satisfactorily some electron-impact induced fragmentation modes, observed in I, I1 and IV, it is necessary to assume that similar processes are operating in the vapour state. Table 1 gives the relative intensities of some significant ions observed in the spectra of these lactones.In unsaturated lactones I to IV, the double bond appears to trigger the primary fragmentation processes. Depending on its location, differences are observed in the fragmentation patterns or in the relative intensities of some fragments. Sometimes, the migration of double bonds induced by electron-impact, alters the expected fragmentation reactions leading to unexpected cleavages.1°The insignificant value of the [M -CH,] ion in V, suggests that the contribution from the methjjl groups at C,, C,, and C,,, to the formation of this ion is negligible. This ion is, however, significant in the lactones I to IV, which is difficult to rationalise. The intensities of these ions in II and IV are comparable with that observed in (-)santonin (33 %), where the major contribution has been proposed to come from the angular methyl group. A concerted cyclization mechanism leading to the elimination of a methyl radical, appears to contribute considerably to the formation of this ion in I1 and IV (Scheme 1).

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A study of santonins and their derivatives by mass spectrometry

Cited by 15 publications

References 23 publications

Mass spectrometric studies of diterpenes: VIII—Epimers

Mass spectrometric studies of diterpenes: VIII—Epimers

Tumor inhibitors. XL. Isolation and structural elucidation of elephantin and elephantopin, two novel sesquiterpenoid tumor inhibitors from Elephantopus elatus

Terpenoids—CXXXVII: Fragmentation of constunolide and its derivatives under electron‐impact

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