Photochemische Reaktionen. 88. Mitteilung [1]. Zur Photochemie des Iso-methyl-β,(E)-jonon-epoxids

Photolysis of iso-methyl-β,(E)-ionone-epoxide On n, π*-excitation (λ ≥ 347 nm) the title compound 7 isomerizes to the (Z)-enone-epoxide 8 , which yields the bicyclic alkohol 9 in a second photochemical step. The photoisomerization 8 → 9 is a further example for the influence of a methyl substituent at C(α) of an enone-chromophore on the nature of the photochemical processes. On UV. irradiation in the presence of traces of hydrochloric acid 7 gives quantitatively the furane 10 .     

Total Synthesis of (±)-α-Acoradiene via Intramolecular Photoaddition and Reductive Cyclobutane Cleavage

(±)-α-Acoradiene (4) has been synthesized from 3-methoxy-2-cyclohexenone by a sequence of 8 steps. The key steps (Scheme 6) are the regio- and stereoselective photo[2+2]addition 7→6 and the reductive fragmentation 6→5 .     

Tri‐ and Bicyclic Taxoids from the Taiwanese Yew Taxus sumatrana

Five new taxoids, including a new 2(3→20)‐abeo‐taxane with a 6/10/6‐membered ring system and four 3,8‐seco‐taxanes having a 6/12‐membered ring system, were isolated from an acetone extract of the leaves and twigs of the Taiwanese yew (Taxus sumatrana, Taxaceae). The structures were established as 2α,7β,10α‐triacetoxy‐5α‐hydroxy‐2(3→20)‐abeo‐taxa‐4(20),11‐dien‐9,13‐dione ( 1 ), (3E,8E)‐2α,9,10β, 13α,20‐pentaacetoxy‐7β‐hydroxy‐3,8‐secotaxa‐3,8,11‐trien‐5‐one ( 2 ), (3E,8E)‐2α,9,10β,13α,20‐pentaacetoxy‐5α,7β‐dihydroxy‐3,8‐secotaxa‐3,8,11‐triene ( 3 ), (3E,8E)‐9,10β,13α‐triacetoxy‐2α,7β,20‐trihydroxy‐5α‐[(2E)‐cinnamoyloxy]‐3,8‐secotaxa‐3,8,11‐triene ( 4 ), and (3E,8E)‐2α,5α,7β,9,10β,13α‐hexaacetoxy‐20‐hydroxy‐3,8‐secotaxa‐3,8,11‐triene ( 5 ), respectively, on the basis 1D‐ and 2D‐NMR spectral analyses. The in vitro cytotoxic activity of compounds 1 – 5 against four human tumor cell lines, including HeLa (cervical epitheloid), WiDr (colon), Daoy (medulloblastoma), and Hep2 (liver carcinoma) tumor cells was evaluated. Whereas compounds 1 – 3 were inactive, the novel taxanes 4 and 5 showed significant cytotoxicity.     

Anatoliosides: Five Novel Acyclic Monoterpene Glylcosides from Viburnum orientale

Five new acyclic monoterpene glycosides 1 – 5 were isolated from the leaves of Viburnum orientale (Caprifoliaceae). Anatolioside ( 1 ) is a monoterpene diglycoside and its structure was elucidated as linalo-6-yl 2′-O-(α-L -rhamnopyranosyl)β-D -glucopyranoside (arbitrary numbering of linalool moiety). Compounds 2 – 5 are all derivatives of 1 , containing additional monoterpene and sugar units, connected by ester and glycoside bonds. Their structures were established as linalo-6-yl O-[(2E,6R)-6-hydroxy-2, 6-dimethylocta-2,7-dienoyl]-(1? → 4″)-O-α-L -rhamnopyranosyl-(1″? → 2″″)-β-D -glucopyranoside ( = anatolioside A; 2 ), linalo-6-yl O-β-D -glucopyranosyl-(1? → 6?)-O-[(2E,6R)-6-hydroxy-2,6-dimethylocta-2,7-dienoyl]-(1? → 4″)-O-α-L -rhamnopyranosyl-(1″ → 2′)–β-D -glucopyranoside ( = anatolioside B; 3 ), linalo-6-yl O-β-D ribo-hexopyranos-3-ulosyl-(1′? → 6?)-O-[(2E,6R)-6-hydroxy-2,6-dimethylocta-2,7-dienoyl]-(1? → 4″)-O-α-L -rhamnopyranosyl-(1″ → 2′)-β-D -glucopyranoside ( = anatolioside C; 4 ) and linalo-6-yl O-[(2E, 6R)-6-hydroxy-2,6-dimethylocta-2,7-dienoyl]-(1″? → 2″″)-O-β-D -glucopyranosly-(1″″ → 6?)-O-[(2E,6R)-6-hydroxy-2,6-dimethylocta-2,7-dienoyl]-(1? → 4″)-O-α-L -rhamnopyranosyl(1″ → 2′)-β-D -glucopyranoside ( = anatolioside D ; 5 ). The structure determinations were based on spectroscopic and chemical methods (acid and alkaline hydrolysis, acetylation and methylation).     

Inhaltsstoffe des Osmanthus-Absolues. 2. Mitteilung: 2,7-Epoxy-megastigma-4,8(E)-dien

Constituents of Osmanthus Absolute, 2nd communication: 2,7-Epoxy-megastigma-4,8 (E)-diene The characteristic fragmentation pattern in the mass spectrum of 2,7-epoxy-dihydro-α-ionone bearing a new oxabridged ionone skeleton has lead to the identification of a further trace component in Osmanthus absolute, the 2,7-epoxy-megastigma-4,8(E)-diene. The synthesis was performed in three steps starting from the above mentioned new ionone derivative now synthetically available by base treatment of 2-hydroxy-α-ionone [1].     

Photochemische Reaktionen. 110. Mitteilung [1]. Zur Photochemie γ,δ-Methano-α-enone

Photochemistry of γ,δ-Methano-α-enones Direct excitation (λ = 254 or ≥ 347 nm) converts the γ,δ-methano-α-enone (E)- 10 into the isomeric ether 23 and the isomeric diene-ketone 24 . Furthermore, on ¹π,π*-excitation (λ = 254 nm) (E)- 10 undergoes an 1,3-homosigmatropic rearrangement yielding the enone (E)- 25 . In addition (E → Z)-isomerization of (E)- 10 and conversion of 10 to the isomeric furan 28 is observed. The isomerization (E)- 10 → 23 , 24 and (E)- 25 proceeds by photocleavage of the C(γ), C(δ)-bond, whereas the formation of 28 occurs by photocleavage the C(γ), C(δ)-bond together with that of the C(γ), C(δ′)-bond of 10 . On direct excitation the bicyclic diene-ether 23 yields the methano-enone 10 , the dieneketone 24 and the tricyclic ether 29 . Evidence is given, that the conversion 23 → 10 is a singulet process. On the other hand, the isomerization 23 → 24 and the intramolecular [2 + 2]-photocycloaddition 23 → 29 are shown to be triplet reactions. Irradiation (λ = 254 nm) of the homoconjugated ketone 24 yields the isomeric ketone 27 by an 1,3-acyl shift. The excitation of the (E)-enone 25 induces (E → Z)-isomerization and photoenolization to give the homoconjugated ketone 26 .     

Terpenoids from Two Dicranopteris Species

Two new compounds, (6S,13S)‐6‐{[β‐D ‐glucopyranosyl‐(1→4)‐α‐L ‐rhamnopyranosyl]oxy}cleroda‐3,14‐dien‐13‐ol ( 1 ) and kadsuric acid 3‐methyl ester ( 2 ), together with nine known compounds, (6S,13E)‐6‐{[β‐D ‐glucopyranosyl‐(1→4)‐α‐L ‐rhamnopyranosyl]oxy}cleroda‐3,13‐dien‐15‐ol ( 3 ), (6S,13S)‐6‐[6‐O‐acetyl‐β‐D ‐glucopyranosyl‐(1→4)‐α‐L ‐rhamnopyranosyl]oxy}‐13‐{[α‐L ‐rhamnopyranosyl‐(1→4)‐β‐D ‐fucopyranosyl]oxy}cleroda‐3,14‐diene ( 4 ), (6S,13S)‐6‐{[6‐O‐β‐D ‐glucopyranosyl‐(1→4)‐α‐L ‐rhamnopyranosyl]oxy}‐13‐{[α‐L ‐rhamnopyranosyl‐(1→4)‐β‐D ‐fucopyranosyl]oxy}cleroda‐3,14‐diene ( 5 ), 15‐hydroxydehydroabietic acid ( 6 ), 15‐hydroxylabd‐8(17)‐en‐19‐oic acid ( 7 ), junicedric acid ( 8 ), (4β)‐kaur‐16‐en‐18‐oic acid ( 9 ), (4β)‐16‐hydroxykauran‐18‐oic acid ( 10 ), and (4β,16β)‐16‐hydroxykauran‐18‐oic acid ( 11 ) were isolated from the fronds of Dicranopteris linearis or D. ampla. Their structures were established by extensive 1D‐ and 2D‐NMR spectroscopy. Compounds 1 and 3 – 8 showed no anti‐HIV activities.     

Novel Sesquiterpenoids from Siegesbeckia orientalis

Five new sesquiterpenoids, namely, 8β‐(angeloyloxy)‐4β,6α,15‐trihydroxy‐14‐oxoguaia‐9,11(13)‐dien‐12‐oic acid 12,6‐lactone ( 1 ), 4β,6α,15‐trihydroxy‐8β‐(isobutyryloxy)‐14‐oxoguaia‐9,11(13)‐dien‐12‐oic acid 12,6‐lactone ( 2 ), 11,12,13‐trinorguai‐6‐ene‐4β,10β‐diol ( 3 ), (1(10)E,4E,8Z)‐8‐(angeloyloxy)‐6α,15‐dihydroxy‐14‐oxogermacra‐(1(10),4,8,11(13)‐tetraen‐12‐oic acid 12,6‐lactone ( 9 ), and (1(10)E,4β)‐8β‐(angeloyloxy)‐6α,14,15‐trihydroxygermacra‐1(10),11(13)‐dien‐12‐oic acid 12,6‐lactone ( 11 ), and three new artifacts, (1(10)E,4Z)‐8β‐(angeloyloxy)‐9α‐ethoxy‐6α,15‐dihydroxy‐14‐oxogermacra‐1(10),4,11(13)‐trien‐12‐oic acid 12,6‐lactone ( 6 ), (1(10)E,4Z)‐8β‐(angeloyloxy)‐9α,13‐diethoxy‐6α,15‐dihydroxy‐14‐oxogermacra‐1(10),4‐dien‐12‐oic acid 12,6‐lactone ( 7 ), and (1(10)E,4Z)‐8β‐(angeloyloxy)‐9α‐ethoxy‐6α,15‐dihydroxy‐13‐methoxy‐14‐oxogermacra‐1(10),4‐dien‐12‐oic acid 12,6‐lactone ( 8 ), together with the three known sesquiterpenoids 4, 5 , and 10 , were isolated from the aerial parts of Siegesbeckia orientalis L. Their structures were established by spectral methods, especially 1D‐ and 2D‐NMR spectral methods.     

Photochemische Reaktionen 114. Mitteilung [1]. Zur Photochemie cyclischer Acetale vom 1,3-Dioxa-4,6-cycloheptadien-Typus

Photochemistry of Cyclic Acetals of the 1,3-Dioxa-4,6-cycloheptadiene Type UV.-irradiation (λ=254 nm) of 3 gives the isomers (E)- 5 (4%), (Z)- 5 (60%) and 6 (3%). On triplet sensitization (acetone; λ ≥ 280 nm) 3 is converted to (E)- 5 (3%), (Z)- 5 (7%) and 7 (9%). ? The ¹π,π*-excitation (λ=254 nm) of 4 yields the isomers 2 (9%), 8 (10%), 9 (34%), 10 (20%) and 11 (3%). On thermolysis (200°) 4 gives 10 (87%) by a Claisen-rearrangement.     

Sterols from the Stems of Momordica charantia

A new sterol, 5α,6α‐epoxy‐3β‐hydroxy‐(22E,24R)‐ergosta‐8,22‐dien‐7‐one ( 1 ), together with eight known sterols, 5α,6α‐epoxy‐(22E,24R)‐ergosta‐8,22‐diene‐3β,7α‐diol ( 2 ), 5α,6α‐epoxy‐(22E,24R)‐ergosta‐8,22‐diene‐3β,7β‐diol ( 3 ), 5α,6α‐epoxy‐(22E,24R)‐ergosta‐8(14),22‐diene‐3β,7α‐diol ( 4 ), 3β‐hydroxy‐(22E,24R)‐ergosta‐5,8,22‐trien‐7‐one ( 5 ), ergosterol peroxide ( 6 ), clerosterol ( 7 ), decortinol ( 8 ), and decortinone ( 9 ), were isolated from the stems of Momordica charantia. Their structures were elucidated by mean of extensive spectroscopic methods, including ¹H, ¹³C, 2D‐NMR and HR‐EI‐MS, as well as comparison with the literature data. Compounds 1 , 4 , 5 , 8 , and 91 were not cytotoxic against the SK‐Hep 1 cell line.     

Three New Atisane Diterpenoids from Spiraea japonica

Three new atisane diterpenoids, spiratisanins A – C ( 1  –  3 , resp.), featuring a phenylacryloxyl substituted ent‐atisane skeleton, were isolated from Spiraea japonica together with two known atisine diterpene alkaloids, spiramine A ( 4 ) and spiradine F ( 5 ). The structures of these new compounds were elucidated as (5β,7α,8α,9β,10α,12α,16β)‐16‐hydroxyatisan‐7‐yl (2E)‐3‐phenylprop‐2‐enoate ( 1 ), (5β,7α,8α,9β,10α,12α,16α)‐16‐hydroxyatisan‐7‐yl (2E)‐3‐phenylprop‐2‐enoate ( 2 ), and (5β,8α,9β,10α,12α,16β)‐16‐hydroxyatisan‐20‐yl (2E)‐3‐phenylprop‐2‐enoate ( 3 ) on the basis of spectroscopic analysis.     

Photochemische Reaktionen. 97 Mitteilung [1]. Zur Photochemie konjugierter Epoxy-diene II. Versuche mit (E)-β-Jonyliden-epoxiden

Photolysis of Conjugated Epoxy-dienes Direct and sensitized excitation of the (E)-β-ionylidene-epoxides 1 and 4 leads to different types of isomerizations. Thus photocycloelimination to the cyclopropene-ketones 2 and 6 is only achieved by ¹(π, π*)-excitation (λ=254 nm), whereas ³(π, π*)-excitation (λ > 280 nm, acetone) gives selective C(1′), O-cleavage of the oxirane ( 1 → 7 – 10 and 4 → 11 – 13 ). In contrast to 1 the twofold methylsubstituted epoxy-diene 4 shows mainly (E/Z)-isomerization ( 4 → 5 ) on both ¹(π, π*)- and ³(π, π*)-excitation while the isomerizations 4 → 6 and 4 → 11 – 13 are minor processes, only.     

Photochemische Reaktionen. 117. Mitteilung [1] Zur Photochemie von 5,6-Epoxydienen und konjugierten 5,6-Epoxytrienen

Photochemistry of 5,6-Epoxydienes and of Conjugated 5,6-Epoxytrienes On singulet excitation (δ = 254 nm) the 5,6-epoxydiene 6 and the conjugated 5,6-epoxytrienes 7 and 8 exclusively give products arising from cleavage of the C, C-bond of the oxirane (cf. 6 → 9 , 10 , 11 ; 7 → (E)- 15 , 16 , 17 ; 8 → 18 (A+B) , 19 (A+B) , 20 , 21 ). The dihydrofuran compounds 11 and (E/Z)- 15 are formed by cyclization of a ketonium-ylide a and d , respectively. Photolysis of a gives the carbene b which yields the cyclopropene 9 , whereas d forms photochemically the carbenes f and g which yield the methano compounds 16 and 17 . The isomeric cyclopropene derivatives 20 and 21 are products of the intermediates h and i , respectively, which are formed by photolysis of the ylide e . The cyclopropene 21 isomerizes by intramolecular cycloadditions to 18 (A+B) and 19 (A+B) . - On triplet excitation (λ?LD nm; 280 nm; acetone) 6 undergoes cleavage of the C(5), O-bond and isomerizes to 12 and 14 . However, 7 is converted by cleavage of the C, C-bond of the oxirane to yield 15 . On treatment with BF₃O(C₂H₅)₂ 6 gives 14 , whereas 7 yields 22 , and 8 forms 23 and 24 .     

Five New Sesquiterpenoids from Parasenecio petasitoides

From the whole plants of Parasenecio petasitoides, five new sesquiterpenoids were isolated, (E,E)‐3α,9β‐dihydroxy‐6βH,11βH‐13‐norgermacra‐1(10),4‐dien‐11,6‐carbolactone ( 2 ), (E,E)‐2α,9β‐dihydroxy‐6βH,11βH‐13‐norgermacra‐1(10),4‐dien‐11,6‐carbolactone ( 3 ), (E,E)‐2α,9β‐dihydroxy‐6βH,11αH‐13‐norgermacra‐1(10),4‐dien‐11,6‐carbolactone ( 4 ), (E)‐15‐hydroxy‐2‐oxo‐6βH,11αH‐13‐norguaia‐3‐ene‐11,6‐carbolactone ( 7 ), and (E)‐11β,15‐dihydroxy‐2‐oxo‐6βH‐13‐norguaia‐3‐ene‐11,6‐carbolactone ( 8 ), together with three known compounds, deacetyl herbolide A ( 1 ), jacquilenin ( 5 ), and (E)‐15‐hydroxy‐2‐oxo‐6βH,11βH‐13‐norguaia‐3‐ene‐11,6‐carbolactone ( 6 ). The structures of these natural products were elucidated spectroscopically, especially by 1D‐ and 2D‐NMR techniques, in combination with high‐resolution mass spectroscopy.     

Photochemical reactions. 137th communication. Preparation and photolysis of (E/Z)-7-methyl-β-ionone

The title compounds (E/Z)- 7 were prepared in 66% overall yield by reaction of β-ionone ((E)-( 1 ) with lithium dimethylcuprate, trapping of the intermediate enolate with benzeneselenenyl bromide and oxidation with H₂O₂. Analogously, (E/Z)-7-methyl-α-inone ((E/Z)- 12 ) was obtained in 65% yield from α-ionone ((E)- 11 ). ¹n, π^*- Excitation (λ > 347 nm, pentane) of (E)-7 causes rapid (E/Z)-isomerization and subsequent reaction of (Z)- 7 to 15 (66%). The formation of 15 is explained by twisting of the dienone chromophore due to repulsive interaction of the 7-CH₃-group with the CH₃-groups of the cyclohexene ring. On the other hand, irradiation λ > 347 nm, Et₂O) of (E)- 7 in the presence of acid leads to (Z)- 7 (5%) and to the novel compound 16 (88%).     

Photochemische Reaktionen. 118. Mitteilung [1] Zur vinylogen β-Spaltung von Enonen. UV.-Bestrahlung von 4-(3',7',7'-Trimethyl-2'-oxabicyclo [3.2.0]hept-3'-en-1'-yl)but-3-en-2-on

Vinylogous β-Cleavage of Enones: UV.-irradiation of 4-(3′,7′,7′-trimethyl-2′-oxabicyclo[3.2.0]hept-3′-ene-1′-yl)but-3-ene-2-on On ¹π,π*-excitation (λ = 254 nm) in acetonitrile (E/Z)- 2 is converted into the isomers 4–9 and undergoes fragmentation yielding 10 ; in methanol (E/Z)- 2 gives 7–10 and is transformed into 11 by incorporation of the solvent. On ¹π,π*-excitation (λ λ?347 nm; benzene-d₆) (E)- 2 is isomerized into (Z)- 2 , which is converted into the isomers 3 and 4 by further irradiation. ¹π,π*-Excitation (λ = 254 nm; acetonitrile) of 4 gives 6 and (E)- 9 , whereas UV.-irradiation (λ = 254 nm; acetonitrile-d₃) of 5 yields (E)- 7 and 8 . On ¹π,π*-excitation (λ = 254 nm; acetonitrile) of (E/Z)- 12 the compounds (E)- 14 and (E)- 15 are obtained.     

Phenylethanoid Glycosides from the Roots of Digitalis ciliata Trautv.

Three new phenylethanoid glycosides, named digicilisides A – C ( 1  –  3 , resp.), have been isolated from the roots of Digitalis ciliata, along with five known phenylethanoid glycosides. The structures of 1  –  3 were identified as 2‐(4‐hydroxy‐3‐methoxyphenyl)ethyl β‐d ‐glucopyranosyl‐(1→3)‐[α‐l ‐rhamnopyranosyl‐(1→6)]‐4‐O‐[(E)‐feruloyl]‐β‐d ‐glucopyranoside ( 1 ), 2‐(3,4‐dihydroxyphenyl)ethyl α‐l ‐arabinopyranosyl‐(1→2)‐[β‐d ‐glucopyranosyl‐(1→3)]‐[α‐l ‐rhamnopyranosyl‐(1→6)]‐4‐O‐[(E)‐feruloyl]‐β‐d ‐glucopyranoside ( 2 ), and 2‐(3,4‐dihydroxyphenyl)ethyl β‐d ‐glucopyranosyl‐(1→3)‐{6‐O‐[(E)‐feruloyl]‐β‐d ‐glucopyranosyl‐(1→6)}‐4‐O‐[(E)‐caffeoyl]‐β‐d ‐glucopyranoside ( 3 ).     

Synthesis and photophysical properties of N‐styrylazinones

N‐Styrylazinones and 1‐styrylbenzotriazine were synthesized, and their photophysical properties were investigated. (Z)‐ and/or (E)‐N‐Styrylazinones (or azine) 4 were prepared from the corresponding heterocycles 1 and benzaldehyde ( 3 ) by four methods. The absorption maxima of (Z)‐ and/or (E)‐ 4a ‐ 4j were measured in four solvents. Their absorption maxima showed a moderate dependence upon solvents. The absorption maxima of (Z)‐isomers were blue‐shifted as compared the corresponding (E)‐isomers. Emission maxima, fluorescence band half‐widths, 0,0 transition energies, Stokes shifts, and quantum yields of (Z)‐ and/or (E)‐ 4a, 4b, 4d, 4e and 4j were measured in organic solvents. The fluorescence spectra show moderate solvatochroism. The fluorescence properties of N‐styrylheterocycles vary with every heterocycles.     

A convenient synthesis of (z)-3-(α-alkoxycarbonyl-α-cyanomethylene)-2-oxo-1,2,3,4-tetrahydroquinoxalines and related compounds

(Z)-3-(α-Alkoxycarbonyl-α-cyanomethylene)-2-oxo-1,2,3,4-tetrahydroquinoxalines 3 and (Z)-3-(α-alkoxycarbonyl-α-cyanomethylene)-3,4-dihydrobenzo[g]quinoxalin-2(1H)-ones 5 possessing various alkoxycarbonyl groups were prepared in good yields directly from the reaction of dialkyl (E)-2,3-dicyanobutendioates 1 with o-phenylenediamine ( 2 ) or with 2,3-diaminonaphthalene ( 4 ), respectively. Furthermore, 2,3-diaminopyridine ( 6 ) and 3,4-diaminopyridine ( 7 ) were reacted with the diethyl ester 1b to give (Z)-2-(α-cyano-α-ethoxycarbonylmethylene)-1,2-dihydro-4H-pyrido[2,3-b]pyrazin-3-one ( 8 ) and (Z)-3-(α-cyano-α-ethoxycarbonylmethylene)-3,4-dihydro-1H-pyrido[3,4-b]pyrazin-2-one ( 9 ), respectively. The structural studies of 3, 5, 8 , and 9 were carried out by nmr experiments in some details.     

Acylated Triterpene Saponins from Atroxima liberica Stapf

The four new acylated triterpene saponins 1 – 4 , isolated as two pairs of isomers and named libericosides A₁/A₂ and B₁/B₂, one pair of isomers 5 / 6 , the (Z)‐isomer libericoside C₂ ( 5 ) being new, one new sucrose ester, atroximoside ( 7 ), and eight known compounds were isolated from the roots of Atroxima liberica by repeated MPLC and VLC on normal and reversed‐phase silica gel. Their structures were elucidated on the basis of extensive 1D‐ and 2D‐NMR studies (¹H‐ and ¹³C‐NMR, DEPT, COSY, TOCSY, NOESY, HSQC, and HMBC) and mass spectrometry as 3‐O‐β‐D ‐glucopyranosylpresenegenin 28‐{O‐α‐L ‐arabinopyranosyl‐(1→3)‐O‐β‐D ‐xylopyranosyl‐(1→4)‐O‐α‐L ‐rhamnopyranosyl‐(1→2)‐4‐O‐[(E)‐3,4‐dimethoxycinnamoyl]‐β‐D ‐fucopyranosyl} ester ( 1 ) and its (Z)‐isomer 2 , 3‐O‐β‐D ‐glucopyranosylpresenegenin 28‐{O‐α‐L ‐arabinopyranosyl‐(1→4)‐O‐β‐D ‐xylopyranosyl‐(1→4)‐O‐α‐L ‐rhamnopyranosyl‐(1→2)‐O‐[O‐β‐D ‐xylopyranosyl‐(1→3)‐β‐D ‐glucopyranosyl‐(1→3)]‐4‐O‐[(E)‐3,4‐dimethoxycinnamoyl]‐β‐D ‐fucopyranosyl} ester ( 3 ) and its (Z)‐isomer 4 , 3‐O‐β‐D ‐glucopyranosylpresenegenin 28‐{O‐β‐D ‐xylopyranosyl‐(1→4)‐O‐α‐L ‐rhamnopyranosyl‐(1→2)‐O‐[6‐O‐acetyl‐β‐D ‐glucopyranosyl‐(1→3)]‐4‐O‐[(Z)‐3,4‐dimethoxycinnamoyl]‐β‐D ‐fucopyranosyl} ester ( 5 ), and 3‐O‐[(Z)‐feruloyl]‐β‐D ‐fructofuranosyl α‐D ‐glucopyranoside ( 7 ). Compounds 1 – 6 and the known saponins 8 / 9 were evaluated against the human colon cancer cells HCT 116 and HT‐29 and showed moderate to weak cytotoxicity.