Cardenolide and pregnane derivatives from the roots of Trachycalymma fimbriatum (Weimark) Bullock. Glycosides and aglycones. 322

The roots of Trachycalymma fimbriatum (WEIMARCK ) BULLOCK contain both cardenolide and pregnaneglycosides. Elimination of 2-deoxysugars by mild acid hydrolysis gave a mixture from which some anhydroderivatives and the following compounds could be isolated: uzarigenin ( l ), ascleposide = 3-O-(6-deoxy-β-D -allopyranosyl)-uzarigenin ( 4 ), coroglaucigenin ( 6 ) and two pregnane derivatives (H and J). Compound H could be identified as 3β,14β-dihydroxy5α, 17α-pregnan-20-one ( 10 ). Compound J is probably a new substance, for which we tentatively assign structure 18 , i.e. 3β8β,14β-trihydroxy-5α,17α-pregnan-20-one. We suspect H and J to be artefacts produced from the corresponding 17b-derivatives during acid hydrolysis. 17-iso-H is probably a precursor in the biosynthesis of uzarigenin. The cardenolides of Trachycalymma fimbriatum are the same as found in Asclepias glaucophylla, a closely related species, while the pregnane derivatives of the latter are distinctly higher hydroxylated.     

20, 21-Azirdin-Steroide: Reaktion von Derivaten der Oxime von 5-Pregnen-20-on,9β,10α-5-Pregnen-20-on und 9β,10α-5,7-Pregnadien-20-on mit Lithiumaluminiumhydrid und von 3β-Hydroxy-5-pregnen-20-on-oxim mit Grignard-Verbindungen

20, 21-Aziridine Steroids: Reaction of Derivatives of the Oximes of 5-Pregnen-20-one, 9β, 10α-5-Pregnen-20-one and 9β, 10α-5,7-Pregnadiene-20-one with Lithium Aluminium Hydride, and of 3β-Hydroxy-5-pregnen-20-one Oxime with Grignard Reagents. Reduction of 3β-hydroxy-5-pregnen-20-one oxime ( 2 ) with LiAlH₄ in tetrahydrofuran yielded 20α-amino-5-pregnen-3β-ol ( 1 ), 20β-amino-5-pregnen-3β-ol ( 3 ), 20β, 21-imino-5-pregnen-3β-ol ( 6 ) and 20β, 21-imino-5-pregnen-3β-ol ( 9 ). The aziridines 6 and 9 were separated via the acetyl derivatives 7 and 10 . The reaction of 6 and 9 with CS₂ gave 5-(3β-hydroxy-5-androsten-17β-yl)-thiazolidine-2-thione ( 8 ). Treatment of the 20-oximes 12 and 15 of the corresponding 9β,10α(retro)-pregnane derivatives with LiAlH₄ gave the aziridines 13 and 16 , respectively. Their deamination led to the diene 14 and triene 17 , respectively. Reduction of isobutyl methyl ketone-oxime with LiAlH₄ in tetrahydrofuran yielded 2-amino-4-methyl-pentane ( 19 ) as main product, 1, 2-imino-4-methyl-pentane ( 22 ) as second product and the epimeric 2,3-imino-4-methyl-pentanes 20 and 21 as minor products. – 3β-Hydroxy-5-pregnen-20-one oxime ( 2 ) was transformed by methylmagnesium iodide in toluene to 20α, 21-imino-20-methyl-5-pregnen-3β-ol ( 23 ) and 20β, 21-imino-20-methyl-5-pregnen-3β-ol ( 26 ). Acetylation of these aziridines was accompanied by elimination reactions leading to 3β-acetoxy-20-methylidene-21-N-acetylamino-5-pregnene ( 30 ) and 3β-acetoxy-20-methyl-21-N-acetylamino-5,17-pregnadiene ( 32 ). The reaction of oxime 2 with ethylmagnesium bromide in toluene gave 20α, 21-imino-20-ethyl-5-pregnen-3β-ol ( 24 ) and 20α,21-imino-20-ethyl-5-pregnen-3β-ol ( 27 ). Acetylation of 24 and 27 led to 3β-acetoxy-20-ethylidene-21-N-acetylamino-5-pregnene ( 31 ), 3β-acetoxy-20-ethyl-21-N-acetylamino-5,17-pregnadiene 33 and 3β, 20-diacetoxy-20-ethyl-21-N-acetylamino-5-pregnene ( 37 ). With phenylmagnesium bromide in toluene the oxime 2 was transformed to 20β, 21-imino-20-phenyl-5-pregnen-3β-ol ( 25 ) and 20β,21-imino-20-phenyl-5-pregnen-3β-ol ( 28 ). Acetylation of 25 and 28 yielded 3β-acetoxy-20-phenyl-21-N-acetylamino-5, 17-pregnadiene ( 34 ) and 3β,20-diacetoxy-20-phenyl-21-N-acetylamino-5-pregnene ( 39 ). LiAlH₄-reduction of 39 gave 3β, 20-dihydroxy-20-phenyl-21-N-ethylamino-5-pregnene ( 41 ). – The 20, 21-aziridines are stable to LiAlH₄. Consequently they are no intermediates in the formation of the 20-amino derivatives obtained from the oxime 2 .     

Photooxygenation of Pregnanes

The course of the singlet‐oxygen reaction with pregn‐17(20)‐enes and pregn‐5,17(20)‐dienes was studied to compare the reactivity of the two alkene moieties present in some steroid families. Thus, from commercially available (3β,5α)‐hydroxy‐androstan‐17‐one and (3β)‐3‐hydroxyandrost‐5‐en‐17‐one, the following 3‐{[(tert‐butyl)dimethylsilyl]oxy}‐substituted, 17(20)‐unsaturated pregnanes were prepared (see Fig. 1): (3β,5α)‐21‐norpregn‐17(20)‐ene 1 ; (3β,5α,17Z)‐pregn‐17(20)‐ene 2 , (3β,5α,16α,17E)‐pregn‐17(20)‐en‐16‐ol 3 , (16β,5α,17E)‐pregn‐17(20)‐en‐16‐ol 4 , (3β,5α,16β,17E)‐pregn‐17(20)‐en‐16‐ol acetate 5 , (3β,16α)‐21‐norpregna‐5,17(20)‐dien‐16‐ol 6 , (3β,16α,17E)‐pregna‐5,17(20)‐dien‐16‐ol 7 , (3β,17Z)‐pregna‐5,17(20)‐diene 8 , (3β,17E)‐pregna‐5,17(20)‐dien‐21‐ol 9 and (3β,17E)‐5,17(20)‐dien‐21‐ol acetate 10 . The oxygenated products (see Fig. 2) obtained from 1 – 10 and ¹O₂, generated by irradiation of Rose Bengal in ³O₂‐saturated pyridine solution, were characterized by ¹H‐, ¹³C‐NMR, and MS (EI, FAB, HR‐EI, ESI‐ and UV‐MALDI‐TOF) data. Major products were those formed by the ene reaction involving as intermediates the corresponding hydroperoxides and the cyclic tautomers of the allylic hydroperoxides, i.e., the corresponding oxiranium oxide‐like intermediate (Scheme 5).     

Vinmajorines C – E,Monoterpenoid Indole Alkaloids from Vinca major

Three new monoterpenoid indole alkaloids, vinmajorines C–E ( 1 – 3 ), along with 18 known analogues ( 4 – 21 ), were isolated from the whole plants of Vinca major. The new structures were elucidated as (5α,15β,16R,17α,19β,20α,21β)‐10,17‐dimethoxy‐21‐methyl‐18‐oxa‐5,16‐cycloyohimban‐19‐ol ( 1 ), (5α,15β,16R,17α,20α,21β)‐10‐methoxy‐21‐methyl‐18‐oxa‐5,16‐cycloyohimban‐17‐ol ( 2 ), and (5α,15β,16R,17α,20α,21β)‐10‐methoxy‐21‐methyl‐18‐oxa‐5,16‐cycloyohimban‐17‐yl acetate ( 3 ), respectively, by extensive NMR and MS analysis and comparison with known compounds. Compounds 1 – 3 were evaluated for their cytotoxic activities against five human cancer cell lines, compounds 1 and 3 showing moderate cytotoxic activities.     

The structure of Genin G(12-O-benzoyl-desacetylmetaplexigenin) and H (di-O-benzoyl-viminolon) from the stems of Sarcostemma viminale (L.) R. Br

The following structures for the two new genins G and H from Sarcostemma viminale have been deduced. Genin G is shown to be 12-O-benzoyl-deacetylmetaplcxigenin ( 3 ). On the basis of physical data, its behaviour in KOH-methanol solution and its positive test with alcaline silver-diammine solution, the structure of 3β, 8β, 14β, 17β-tetrahydroxy-12β, 21-dibenzoyloxy-20-oxo-17α-pregn-5-ene ( 4 ) is proposed for genin H. This substance therefore contains a dihydroxyacetone group like some corticoids (e.g. Cortisol), but with different stereochemistry at C-14 and C-17.     

Steroidal quinoxalines

The treatment of 3β-hydroxy-16α-bromo-5α-androstan-17-one, 3β-acetoxy-16α-bromo-5-androsten-17-one and 21-bromo-5-pregnen-3β-ol-20-one with 4,5-dimethyl-o-phenylenediamine gave substituted quinoxalines. Hydrolysis of 3β-acetoxy-5-androsteno[16,17-b]-6′,7′-dimethylquinoxaline produced the corresponding 3β-hydroxy compound. 3-Oxo-4-androsteno[16,17-b]-6′,7′-dimethylquinoxaline was obtained by Oppenauer oxidation of the corresponding alcohol.     

Glykoside von Marsdenia erecta R. Br. 2. Mitteilung: Versuche zur Strukturbestimmung der Genine. Glykoside und Aglykone, 330. Mitteilung

Structures for the genins of the ester glycosides of Marsdenia erecta are suggested. They are based on the behaviour in alkaline hydrolysis of these ester glycosides, their NMR. and mass spectra and ORD. data. All genins are derived from three acyl-free pregnane derivatives, i.e. drevogenin-P ( 1 ), 17 β-marsdenin ( 3 ) and marsectohexol ( 7 ). The structure of 1 is known, 3 and 7 are new compounds, i.e. 3 = 3β,8β,11α,12β,14β-pentahydroxy-Δ⁵-pregnen-20-one and 7 = 3β,8β,11α,12β,14β,20ξ-hexahydroxy-Δ⁵-pregnene. Formulae 13–17 were attributed to the acyl-genins A-1, A-2, A-3, A-4 and A-5, but only two of them were pure compounds, i.e. acyl-genin A-3 = 11,12-di-O-tiglyl-17β-marsdenin ( 15 ) and acyl-genin A-5 = 11,12-di-O-acetyl-marsectohexoi ( 17 ). Acyl-genin A-1 is a mixture of the two esters 13a + 13b derived from drevogenin-P, and similarly acyl-genin A-2 is a mixture of the esters 14a + 14b derived from 17β-marsdenin. The poorly characterised acyl-genin A-4 is most probably a mixture of the esters 16a + 16b , also derived from 17β-marsdenin.     

Synthesis of nitrogen-containing derivatives of 17(20)-pregnenoic, 17β-hydroxypregnanoic,and 17α-hydroxypregnanoic acids as new potential antiandrogens

A general scheme for the synthesis of oxazoline and benzoxazole derivatives of [17(20)E]-21-norpregnene differing in the structure of the steroid moiety as well as amides of 17β-hydroxy-3-oxopregn-4-en-21-oic and 17α-hydroxy-3-oxopregn-4-en-21-oic acids was developed. The scheme involved synthesis of the steroid building blocks (appropriately protected derivatives of pregn-17(20)-en-21-oic, 17β-hydroxypregnan-21-oic, and 17α-hydroxypregnan-21-oic acids) and subsequent transformation of these building blocks into the target compounds. Following the developed scheme, synthesis of new nitrogen-containing steroid derivatives exhibiting antiandrogenic activity was enabled.     

Steroidal imidazopyridines and lactam imidazopyridines

Condensation of 17β-acetoxy-2α-bromo-5α-androstan-3-one with unsubstituted and substituted amino-pyridines, gives the corresponding 17β-acetoxy-5α-androstanimidazo[1,2-a]pyridines. Treatment of 16α-bromo-3-aza-A-homo-4α-androsten-4,17-dione with 2-aminopyridine or methyl-2-aminopyridine produces the corresponding 3-aza-A-homo-4α-androsten[16,17:2′,3′]imidazo[1,2-a]pyridines. Similarly, from 2α-bromo-17β-acetamido-5α-androstan-3-one and methylaminopyridine the 17β-acetamido-5α-androstan[2,3:2′,3′]imidazo[1,2-a]methylpyridine has been obtained. The structure of the compounds was apparent from their chemical properties and spectral data (ir, uv and nmr).     

Oxetane from A-nor-steroides: 2-alpha, 5-oxido-A-nor-5-alpha-cholestane, 2-beta, 5-oxido-A-nor-5-beta-cholestane and 2-alpha-ethyl-2-beta,2'-oxido-A-nor-5-alpha-cholestane

Treatment of 2β-tosyloxy-A-nor-5α-cholestane-5-ol ( 2 ) with t-butoxide in t-butanol gave 2α, 5-epoxy-A-nor-5α-cholestane ( 3 ) in quantitative yield. When A-nor-5β-cholestane-2α, 5-diol ( 4 ) was treated with tosyl chloride in pyridine 2β-chloro-A-nor-5β-cholestane-5-ol ( 7 ) and 2α-tosyloxy-A-nor-5β-cholestane-5-ol ( 8 ) were obtained. Whereas the chloride 7 was resistant to t-butoxide the tosylate 8 was transformed into an 1 : 1 mixture of 2α, 5-epoxy-5β-cholestane ( 10 ) and 2ξ-t-butoxy-A-nor-5β-cholestane-5-ol ( 11 ). In 2α-tosyloxy-A-nor-5α-cholestane-5-ol ( 12 ) substitution occurred as the only reaction. Both oxetanes 3 and 10 isomerize after heating above 50° and in polar or protic solvents to form A-nor-Δ³⁽⁵⁾-cholestene-2α-ol ( 6 ) and -2β-ol ( 14 ) respectively. Also, 2, 5-diols are encountered. 2α-Ethyl-2β, 2′-epoxy-A-nor-5α-cholestane ( 23 ) was synthesized starting from A-nor-5α-cholestane-2-one ( 17 ). The intermediates were the ester 16 , the diol 18 , the hydroxy-tosylate 19 and the chlorhydrin 20 . The spirocyclic oxetane 23 was reduced by LiAlH₄ in dioxane (not in ether). By chromatography on silica gel 23 was isomerized to the homoallylic alcohol 21 and transformed into 2-methylene-A-nor-5α-cholestane ( 24 ) by fragmentation. The IR. and NMR. spectra of the new oxetanes were compared with those of a series of known oxetanes.     

Synthesis and biological evaluation of 3-beta,20(R)-dihydroxy-protost-24-ene

The possible lanosterol precursor, 3β, 20(R)-dihydroxy-protost-24-ene ( 1 a ) has been prepared, in thirteen steps, from 3α-hydroxy-4α, 8, 14-trimethyl-18-nor-5α, 8α, 9β, 13ξ, 14β-androstan-17-one (mixture of 2 and 3 ). In vitro experiments with rat liver homogenates failed to convert 1 a to lanosterol.     

Synthesis,structure, and acylation of dihydroquinopimaric acid hydroxy derivatives

Reduction conditions of methyl dihydroquinopimarate with sodium borohydride and lithium aluminum hydride were established. As a result of the reduction 14β-hydroxy, 17α-hydroxy, 14β,17α-dihydroxy, and 14β,17α,21α-trihydroxy derivatives were obtained. The structure of methyl esters of 14β-acetoxy- and 17α-hydroxydihydroquinopimaric acid was established by XRD and NMR methods. Mono-, di-, and triacylates were obtained from the diterpene alcohols.     

Androstane‐Type Steroidal Glycoside from the Roots of Asparagus curillus Buch.‐Ham. ex Roxb.

The novel androstane‐type steroidal glycoside 1 was isolated from the roots of Asparagus curillus Buch .‐Ham . ex Roxb . Its structure was elucidated as (2α,3β,5α,17β)‐17‐(1‐methoxyethoxy)‐17‐methylandrostane‐2,3‐diol 3‐(β‐D ‐digitoxopyranoside) by means of chemical and advanced spectral analysis.     

A New Cardenolide and Two New Pregnane Glycosides from the Root Barks of Periploca sepium

A new cardenolide and two new pregnane glycosides, periplogenin 3‐[O‐β‐glucopyranosyl‐(1→4)‐β‐sarmentopyranoside] ( 1 ), (3β,20S)‐pregn‐5‐ene‐3,17,20‐triol 20‐[O‐β‐glucopyranosyl‐(1→6)‐O‐glucopyranosyl‐(1→4)‐β‐canaropyranoside] ( 2 ), and (3β,14β,17α)‐3,14,17‐trihydroxy‐21‐methoxypregn‐5‐en‐20‐one 3‐[O‐β‐oleandropyranosyl‐(1→4)‐O‐β‐cymaropyranosyl‐(1→4)‐β‐cymaropyranoside] ( 3 ), were isolated from the root barks of Periploca sepium Bge , together with seven related known compounds, periplogenin, xysmalogenin, (3β,20S)‐pregn‐5‐ene‐3,17,20‐triol, (3β,14β,17α)‐3,14,17‐trihydroxy‐21‐methoxypregn‐5‐en‐20‐one, (3β,20S)‐pregn‐5‐ene‐3,20‐diol 3‐β‐glucopyranoside 20‐β‐glucopyranoside, (3β,20S)‐pregn‐5‐ene‐3,20‐diol 3‐[O‐2‐O‐acetyl‐β‐digitalopyranosyl‐(1→4)‐β‐cymaropyranoside] 20‐[O‐β‐glucopyranosyl‐(1→6)‐O‐β‐glucopyranosyl‐(1→2)‐β‐digitalopyranoside], and (3β,20S)‐ pregn‐5‐ene‐3,20‐diol 20‐[O‐β‐glucopyranosyl‐(1→6)‐β‐glucopyranoside]. Their structures were elucidated on the basis of spectroscopic analyses.     

21α‐Fluoro‐7‐norvouacapane‐17β,21α‐lactone

The crystal structure of 21α‐fluoro‐7‐norvouacapane‐17β,21α‐lactone, C₂₀H₂₅FO₃, a new synthetic derivative of the diterpenoid 6α,7β‐di­hydroxy­vouacapan‐17β‐oic acid isolated from Pterodon polygalaeflorus Benth fruits, is described.     

Cardenolides and Cardiac Aglycone from the Stem Bark of Trewia nudiflora

Five new cardenolides and one new cardiac aglycone, i.e., (5α)‐sarmentogenin 3‐(α‐L ‐rhamnopyranoside) ( 1 ), (5α)‐sarmentogenin ( 2 ), 11‐oxouzarigenin 3‐(α‐L ‐rhamnopyranoside) ( 3 ), (5α)‐gitoxigenin 3‐(α‐L ‐rhamnopyranoside) ( 4 ), (5α)‐oleandrigenin 3‐(α‐L ‐rhamnopyranoside) ( 5 ), and (5α)‐oleandrigenin 3‐[β‐D ‐glucopyranosyl‐(1 → 4)‐α‐L ‐rhamnopyranoside] ( 6 ), together with two known cardenolides, i.e., frugoside (= (3β,5α)‐3‐[(6‐deoxy‐β‐D ‐allopyranosyl)oxy]‐14,19‐dihydroxycard‐20(22)‐enolide) and (17α)‐ascleposide (= (3β,5α,17α)‐3‐[(6‐deoxy‐α‐D ‐allopyranosyl)oxy]‐14‐hydroxycard‐20(22)‐enolide), were isolated from the stem bark of Trewia nudiflora L. (Euphorbiaceae) collected in Xishuangbanna, Yunnan Province, China. Their structures were established by spectroscopic studies. Cardenolides were first found in the genus Trewia (Euphorbiaceae).     

Cholinesterase‐Inhibiting New Steroidal Alkaloids from Sarcococca hookeriana of Nepalese Origin

Bioassay‐guided phytochemical investigation of Sarcococca hookeriana has resulted in the isolation and structure elucidation of five new pregnane‐type steroidal alkaloids: (?)‐hookerianamide A (=(2β,3β,4β,20S)‐20‐(dimethylamino)‐3‐[(3‐methylbut‐2‐enoyl)amino]‐5α‐pregn‐16‐ene‐2,4‐diol; 1 ), (+)‐hookerianamide B (=(2α,3β,4β,20S)‐4‐acetoxy‐20‐(dimethylamino)‐3‐[(3‐methylbut‐2‐enoyl)amino]‐5α‐pregnan‐2‐ol; 2 ), (?)‐hookerianamide C (=(2β,3β,20S)‐2‐acetoxy‐20‐(dimethylamino)‐3‐[(3‐methylbut‐2‐enoyl)amino]‐5α‐pregnane; 3 ), (?)‐hookerianamine A (=(3β,20S)‐20‐(dimethylamino)‐3‐(methylamino)‐5α‐pregn‐14‐ene; 4 ), and (+)‐phulchowkiamide A (=(3β,20S)‐20‐(methylamino)‐3‐[(2‐methylbut‐2‐enoyl)amino]‐5α‐pregn‐2‐en‐4‐one; 5 ). These compounds, as well as the two chemically derived acetyl derivatives 6 and 7 , displayed cholinesterase inhibition in a concentration‐dependent manner.     

A Hydroxylated Lupeol‐Based Triterpenoid Ester Isolated from the Scurrula parasitica Parasitic on Nerium indicum

(3β,7β)‐7‐Hydroxylup‐20(29)‐en‐3‐yl hexadecanoate ( 1 ), a new lupeol‐based triterpenoid ester, along with sixteen known compounds, 7β,15α‐dihydroxylup‐20(29)‐ene‐3β‐O‐palmitate ( 2 ), lupeol palmitate ( 3 ), lupeol ( 4 ), 3‐oxolup‐20(29)‐ene ( 5 ), ursolic acid ( 6 ), cycloeucalenol ( 7 ), stigmasterol ( 8 ), β‐sitosterol ( 9 ), β‐daucosterol ( 10 ), quercetin ( 11 ), quercetin 3‐O‐α‐L ‐arabinoside ( 12 ), quercetin 3‐O‐α‐L ‐rhamnoside ( 13 ), catechin ( 14 ), gitoxigenin 3‐O‐α‐L ‐rhamnoside ( 15 ), gitoxigenin 3‐O‐α‐D ‐glucoside ( 16 ), and digitoxigenin 3‐O‐α‐L ‐rhamnoside ( 17 ), was isolated from the leaves of the Southern China mistletoe, Scurrula parasitica Linn parasitic on Nerium indicum Mill . Their structures were elucidated by spectroscopic analyses, including 2D‐NMR techniques. Cytotoxic activities of compounds 1 – 7 and 11 – 17 were evaluated against three cancer cell lines, PANC‐1, HL‐60, and SGC‐7901, revealing that compounds 4, 6, 11 , and 15 – 17 exhibited effective cytotoxicities, while others were inactive. A structure? activity relationship study of compounds 1 – 5 indicated that the 3‐OH group in lupeol‐based triterpenoids is essential for antitumor activity.     

The synthesis of β-heteroarylamino-α,β-dehydro-α-amino acid derivatives via thiazolones

2-Alkoxy-4-heteroarylaminomethylene-5(4H)-thiazolones 4 were converted with various nucleophiles into β-heteroarylamino-α,β-dehydro-α-amino acid derivatives 11, 14, 15, 16, 17, 18 , and 19 . Reduction of 4 with sodium borohydride in ethanol saturated with gaseous ammonia afforded the corresponding β-heteroaryl-amino substituted alanyl amides 20 . Thiazoledione derivative 7a was transformed with sodium methoxide in methanol into 1-(4,6-dimethylpyrimidinyl-2)-4-mercaptocarbonylimidazol-2(3H)-one ( 8a ).     

Three New C21 Steroidal Glycosides from the Stems of Marsdenia tenacissima

Three new glycosides, (3β,5α,8α,11α,12β,14β,17α,20R)‐3‐[(2,6‐dideoxy‐4‐O‐(6‐deoxy‐3‐O‐methyl‐β‐D ‐allopyranosyl)‐3‐O‐methyl‐β‐D ‐arabino‐hexopyranosyl)oxy]‐12‐O‐tigloyl‐8,20 : 11,20‐diepoxypregnane‐12,14‐diol ( 1 ), (3β,5α,8α,11α,12β,14β,17α,20R)‐3‐[(2,6‐dideoxy‐4‐O‐(6‐deoxy‐3‐O‐methyl‐β‐D ‐ allopyranosyl)‐3‐O‐methyl‐β‐D ‐arabino‐hexopyranosyl)oxy]‐12‐O‐(2‐methylbutanoyl)‐8,20 : 11,20‐diepoxypregnane‐12,14‐diol ( 2 ), and (3β,5α,11α,12β,14β,17α)‐12‐acetoxy‐3‐[(2,6‐dideoxy‐4‐O‐(6‐deoxy‐3‐O‐methyl‐β‐D ‐allopyranosyl)‐3‐O‐methyl‐β‐D ‐arabino‐hexopyranosyl)oxy]‐20‐oxo‐8,14‐epoxypregnan‐ 11‐yl isobutyrate ( 3 ) were isolated from the stems of Marsdenia tenacissima. The structures of the new compounds were elucidated by means of spectral data, including HR‐ESI‐MS, and 1D‐ and 2D‐NMR.