iso-PsE, a new pseudopterosin

We describe the discovery of a new member of the pseudopterosin class of marine natural products. Its structure is isomeric with that of pseudopterosin E and has therefore been given the name iso-PsE.     

Synthese von N-Methyl- und N,N-Dimethylmerucathin sowie von N-Methyl- und N,N-Dimethylpseudomerucathin aus L-Alanin

Synthesis of N-Methyl- and N,N-Dimethylmerucathine and of N-Methyl- and N,N--Dimethylpseudomerucathine Starting from L -Alanine Starting form L -alanine, N-methylmerucathine (= (3R,4S)-4-(methylamino)1-phenyl-1-penten-3-ol; (3R,4S,)- 6 ), N,N-dimethylmerucathine (= (3R,4S)-4-(dimethylamino)-1-phenyl-1-penten-3-ol; (3R,4S)- 9 ), N-methylpseudomerucathine (= (3S,4S)-4-(methylamino)-1-phenyl-1-penten-3-01; (3S,4S)-6), and N,N-dimethylpseudomerucathine (= (3S,4S)-4-(dimethylamino)-1-phenyl-1-penten-3-ol; (3S,4S)- 9 ) were synthesized. The four compounds were analyzed by HPLC and compared with a natural khat extract.     

Nine New Sesquiterpenes from Dendrobium nobile

Nine new sesquiterpenes, i.e., dendronobilins A–I ( 1 – 9 ), with copacamphane‐type ( 1 ), picrotoxane‐type ( 2 – 6 ), muurolene‐type ( 7 ), alloaromadendrane‐type ( 8 ), and cyclocopacamphane‐type ( 9 ) skeletons, were isolated from the 60% EtOH extract of the stems of Dendrobium nobile. Their structures were established as (1R,2R,4S,5S,6S,8S,9R)‐2,8‐dihydroxycopacamphan‐15‐one ( 1 ), (2β,3β,4β,5β)‐2,4,11‐trihydroxypicrotoxano‐3(15)‐lactone ( 2 ), (2β,3β,5β,9α,11β)‐2,11‐epoxy‐9,11,13‐trihydroxypicrotoxano‐3(15)‐lactone ( 3 ), (2β,3β,5β,12R*)‐2,11,13‐trihydroxypicrotoxano‐3(15)‐lactone ( 4 ), (2β,3β,5β,12S*)‐2,11,13‐trihydroxypicrotoxano‐3(15)‐lactone ( 5 ), (2β,3β,5β,9α)‐9,10‐cyclo‐2,11,13‐trihydroxypicrotoxano‐3(15)‐lactone ( 6 ), (9β,10α)‐muurol‐4‐ene‐9,10,11‐triol ( 7 ), (10α)‐alloaromadendrane‐10,12,14‐triol ( 8 ), and (5β)‐cyclocopacamphane‐5,12,15‐triol ( 9 ) on the basis of spectroscopic analysis. The absolute configuration of compound 1 was tentatively assigned as (1R,2R,4S,5S,6S,8S,9R) according to its CD spectrum and the octant rule. Compounds 1 and 4 – 9 were inactive in our preliminary in vitro immunomodulatory bioassay.     

Efficient route to 2H-1,3-oxazines through ring expansion of isoxazoles by rhodium carbenoids

Studies related to the total synthesis of elisabethin C led to the discovery of a rhodium-catalyzed cascade sequence involving isoxazole ring expansion and a [4+3] cycloaddition. The scope of the isoxazole ring expansion was explored, resulting in the synthesis of a range of 2H-1,3-oxazines in 47-96% yield.     

Carotenoids of Rhizobia. IV. Isolation and structure elucidation of the carotenoids of a mutant of Rhizobium lupini

The structures of the main carotenoid pigments from the mutant 1-207 of Rhizobium lupini were elucidated by spectroscopic techniques (UV./VIS., CD., 270 MHz ¹H-NMR., and MS.). Ten carotenoids were identified, namely β,β-carotene ( 1 ), β,β-caroten-4-one (echinenone, 2 ), β,β-carotene-4,4′-dione (canthaxanthin, 3 ), (3S)-3-hydroxy-β,β-caroten-4-one ((3S)-3-hydroxyechinenone, 4 ), (2R, 3R)-β,β-carotene-2,3-diol ( 5 ), (3S)-3-hydroxy-β,β-carotene-4,4′-dione ((3S)-adonirubin, 6 ), (2R, 3S)-2,3-dihydroxy-β,β-caroten-4-one ( 7 ), (2R, 3S)-2,3-dihydroxy-β,β-caroten-4,4′-dione ( 8 ), (2R, 3S, 2′R, 3′R)-2,3,2′,3′-tetrahydroxy-β,β-caroten-4-one ( 9 ) and the corresponding (2R, 3S, 2′R, 3′S)-4,4′-dione ( 10 ). Structures 5, 7, 8 and 10 have not been reported before. From the observed carotenoid pattern it is concluded that in this mutant the oxidation to 4-oxo compounds is favoured compared to the hydroxylation at C(3) and C(2).     

Three New Triterpenoids from Lycopodium japonicum Thunb

Three new triterpenoids, (3β,8β,14α,21α)‐26,27‐dinoronocerane‐3,8,14,21‐tetrol ( 1 ), (3β,8β,14α,21β)‐26,27‐dinoronocerane‐3,8,14,21‐tetrol ( 2 ), and lycopodiin A ( 3 ), together with four known compounds, lycoclavanol ( 4 ), lycoclaninol ( 5 ), α‐onocerin ( 6 ), and 3‐epilycoclavanol ( 7 ), were isolated from Lycopodium japonicum Thunb (Lycopodiaceae). Their structures were established by means of spectroscopic analyses. Compounds 3 and 7 showed moderate antitumor activity. Compounds 4 and 6 exhibited acetylcholinesterase inhibition activity.     

Breaking the Mirror: pH‐Controlled Chirality Generation from a meso Ligand to a Racemic Ligand

To study the conversion from a meso form to a racemic form of tetrahydrofurantetracarboxylic acid (H₄L), seven novel coordination polymers were synthesized by the hydrothermal reaction of Zn(NO₃)₂ ? 6 H₂O with (2S,3S,4R,5R)‐H₄L in the presence of 1,10‐phenanthroline (phen), 2,2′‐bipyridine (2,2′‐bpy), or 4,4′‐bipyridine (4,4′‐bpy): [Zn₂{(2S,3S,4R,5R)‐L}(phen)₂(H₂O)] ? 2 H₂O ( 1 ), [Zn₄{(2S,3R,4R,5R)‐L}{(2S,3S,4S,5R)‐L}(phen)₂(H₂O)₂] ( 2 ), [Zn₂{(2S,3S,4R,5R)‐L}(H₂O)₂] ? H₂O ( 3 ), [Zn₄{(2S,3R,4R,5R)‐L}{(2S,3S,4S,5R)‐L} (2,2′‐bpy)₂(H₂O)₂] ? 2 H₂O ( 4 ), [Zn₂ {(2S,3S,4R,5R)‐L}(2,2′‐bpy)(H₂O)] ( 5 ), [Zn₄{(2S,3R,4R,5R)‐L}{(2S,3S,4S,5R)‐L} (4,4′‐bpy)₂(H₂O)₂] ( 6 ), and [Zn₂ {(2S,3S,4R,5R)‐L}(4,4′‐bpy)(H₂O)] ? 2 H₂O ( 7 ). These complexes were obtained by control of the pH values of reaction mixtures, with an initial of pH 2.0 for 1 , 2.5 for 2 , 4 , and 6 , and 4.5 for 3 , 5 , and 7 , respectively. The expected configuration conversion has been successfully realized during the formation of 2 , 4 , and 6 , and the enantiomers of L, (2S,3R,4R,5R)‐L and (2S,3S,4S,5R)‐L, are trapped in them, whereas L ligands in the other four complexes retain the original meso form, which indicates that such a conversion is possibly pH controlled. Acid‐catalyzed enol–keto tautomerism has been introduced to explain the mechanism of this conversion. Complex 1 features a simple 1D metal–L chain that is extended into a 3D supramolecular structure by π–π packing interactions between phen ligands and hydrogen bonds. Complex 2 has 2D racemic layers that consist of centrosymmetric bimetallic units, and a final 3D supramolecular framework is formed by the interlinking of these layers through π–π packing interactions of phen. Complex 3 is a 3D metal–organic framework (MOF) involving meso‐L ligands, which can be regarded as (4,6)‐connected nets with vertex symbol (4⁵.6)(4⁷.6⁸). Complexes 4 and 5 contain 2D racemic layers and (6,3)‐honeycomb layers, respectively, both of which are combined into 3D supramolecular structures through π–π packing interactions of 2,2′‐bpy. The structure of complex 6 is a 2D network formed by 4,4′‐bpy bridging 1D tubes, which consist of metal atoms and enantiomers of L. These layers are connected through hydrogen bonds to give the final 3D porous supramolecular framework of 6 . Complex 7 is a 3D MOF with novel (3,4,5)‐connected (6³)(4².6⁴)(4².6⁶.8²) topology. The thermal stability of these compounds was also investigated.     

Three New Sesquiterpenoids from Echinops ritro L.

From the whole plants of E. ritro L., the three new sesquiterpenoids (3α,4α,6α)‐3,13‐dihydroxyguaia‐7(11),10(14)‐dieno‐12,6‐lactone ( 1 ), (3α,4α,6α,11β)‐3‐hydroxyguai‐1(10)‐eno‐12,6‐lactone ( 2 ), and (11α)‐11,13‐dihydroarglanilic acid methyl ester (=(4β,6α,11α)‐4,6‐dihydroxy‐1‐oxoeudesm‐2‐en‐12‐oic acid methyl ester; 3 ), together with eight known sesquiterpenoids, were isolated. Their structures were elucidated through analysis of spectroscopic data including extensive 2D‐NMR.     

Neoclerodane Diterpenes from Amoora stellato‐squamosa

From the twigs of Amoora stellato‐squamosa, five new neoclerodane diterpenes have been isolated and characterized, methyl (13E)‐2‐oxoneocleroda‐3,13‐dien‐15‐oate (=methyl (2E)‐3‐methyl‐5‐[(1S,2R,4aR,8aR)‐1,2,3,4,4a,7,8,8a‐octahydro‐1,2,4a,5‐tetramethyl‐7‐oxo‐naphthalen‐1‐yl]pent‐2‐enoate; 1 ), (13E)‐2‐oxoneocleroda‐3,13‐dien‐15‐ol (=(4aR,7R,8S,8aR)‐1,2,4a,5,6,7,8,8a‐octahydro‐8‐[(E)‐5‐hydroxy‐3‐methylpent‐3‐enyl]‐4,4a,7,8‐tetramethylnaphthalen‐2(1H)‐one; 2 ), (3α,4β,13E)‐neoclerod‐13‐ene‐3,4,15‐triol (=(1R,2R,4aR, 5S,6R,8aR)‐decahydro‐5‐[(E)‐5‐hydroxy‐3‐methylpent‐3‐enyl]‐1,5,6,8a‐tetramethylnaphthalene‐1,2‐diol; 3 ), (3α,4β,13E)‐4‐ethoxyneoclerod‐13‐ene‐3,15‐diol (=(1R,2R,4aR,5S,6R,8aR)‐1‐ethoxydecahydro‐5‐[(E)‐5‐hydroxy‐3‐methylpent‐3‐enyl]‐1,5,6,8a‐tetramethylnaphthalen‐2‐ol; 4 ), and (3α,4β,14RS)‐neoclerod‐13(16)‐ ene‐3,4,14,15‐tetrol (=(1R,2R,4aR,5S,6R,8aR)‐decahydro‐5‐[3‐(1,2‐dihydroxyethyl)but‐3‐enyl]‐1,5,6,8a‐tetramethylnaphthalene‐1,2‐diol; 5 ), together with two known compounds, (13E)‐neocleroda‐3,13‐diene‐15,18‐diol ( 6 ) and (13S)‐2‐oxoneocleroda‐3,14‐dien‐13‐ol ( 7 ).     

Ceramides Isolated from Helianthus annuus L.

Three new compounds (2R)‐2‐hydroxy‐N‐[(2S,3S,4R,10E)‐1,3,4‐trihydroxyicos‐10‐en‐2‐yl]docosanamide ( 1 ), (2R,3R)‐2,3‐dihydroxy‐N‐[(2S,3S,4R,10E)‐1,3,4‐trihydroxyicos‐10‐en‐2‐yl]docosanamide ( 2 ), N‐(2‐phenylethyl)tetracosanamide ( 3 ), together with a known ceramide, (2R)‐N‐[(2S,3S,4R,8E)‐1‐(β‐D ‐Glucopyranosyloxy)‐3,4‐dihydroxyoctadec‐8‐en‐2‐yl]‐2‐hydroxyhexadecanamide ( 4 ), were isolated from acetone extract of flower disc of Helianthus annuus L. The structures were identified on the basis of chemical and spectroscopic methods.     

Sesquiterpenoids and Lactone Derivatives from Ligularia dentata

Seven new compounds were isolated from the roots of Ligularia dentata, including five bisabolane‐type sesquiterpenoids (bisabolane=1‐(1,5‐dimethylhexyl)‐4‐methylcyclohexane), namely (8β,10α)‐8‐(angeloyloxy)‐5,10‐epoxybisabola‐1,3,5,7(14)‐tetraene‐2,4,11‐triol ( 1 ), (8β,10α)‐8‐(angeloyloxy)‐5,10‐epoxythiazolo[5,4‐a]bisabola‐1,3,5,7(14)‐tetraene‐4,11‐diol ( 2 ), (1α,2α,3β,5α,6β)‐1,5,8‐tris(angeloyloxy)‐10,11‐epoxy‐2,3‐dihydroxybisabol‐7(14)‐en‐4‐one ( 3 ), (1α,2α,3β,5α,6β)‐2,5,8‐tris(angeloyloxy)‐10,11‐epoxy‐1,3‐dihydroxybisabol‐7(14)‐en‐4‐one ( 4 ), and (1α,2β,3β,5α,6β)‐1,8‐bis(angeloyloxy)‐2,3‐epoxy‐5,10‐dihydroxy‐11‐methoxybisabol‐7(14)‐en‐4‐one ( 5 ) (angeloyloxy=[(2Z)‐2‐methyl‐1‐oxobut‐2‐enyl]oxy), and two lactone derivatives, (2α,3β,5α)‐2‐(acetyloxy)‐9‐methoxy‐5‐(methoxycarbonyl)‐2,3‐dimethylheptano‐5‐lactone ( 6 ), and (2β,4β)‐2‐ethyl‐5‐hydroxy‐5‐(methoxycarbonyl)‐4,5‐dimethylpentano‐4‐lactone ( 7 ) (α/β denote relative configurations), together with (2E,4R,5S)‐2‐ethylidene‐5‐(methoxycarbonyl)‐4‐methylhexano‐5‐lactone ( 8 ), a known synthetic compound. Compound 2 is the first sesquiterpenoid derivative containing the uncommon benzothiazole moiety. The structures of 1 – 8 were established by spectroscopic methods, especially 2D‐NMR and MS analyses.     

Syntheses,crystal structures and fluorescent properties of four one-dimensional lanthanide coordination polymers with 3-cyanobenzoato

The hydrothermal reactions of Nd(ClO₄)₃·6H₂O, Gd(ClO₄)₃·6H₂O, Dy(ClO₄)₃·6H₂O, Er(ClO₄)₃·6H₂O with 1,3-dicyanobenzene, give rise to four one-dimensional rare earth-based coordination polymers: [M(3-CNC₆H₄COO)₃(H₂O)₂] _n (where M?=?Nd (1), Gd (2), Dy (3), Er (4), 3-CNC₆H₄COO?=?3-cyanobenzoato), respectively. Their solid-state structures have been characterized by X-ray single-crystal diffraction studies. The results show that 1,3-dicyanobenzene hydrolyzed to give 3-cyanobenzoato under hydrothermal condition, and the four complexes are isomorphous. Crystal data for 1: triclinic, space group P-1, a?=?9.4063(19), b?=?11.485(2), c?=?12.616(3)?Å, α?=?66.38(3), β?=?74.01(3), γ?=?86.96(3)°, V?=?1197.9(4)?ų, Z?=?1, D _c?=?1.704?Mg?m^?3; for 2: triclinic, space group P-1, a?=?9.3712(19), b?=?11.446(2), c?=?12.627(3)?Å, α?=?65.86(3), β?=?73.89(3), γ?=?86.84(3)°, V?=?1184.8(4)?ų, Z?=?1, D _c?=?1.759?Mg?m^?3; for 3: triclinic, space group P-1, a?=?9.3425(19), b?=?11.432(2), c?=?12.703(3)?Å, α?=?65.28(3), β?=?73.80(3), γ?=?86.86(3)°, V?=?1180.6(4)?ų, Z?=?1, D _c?=?1.780?Mg?m^?3; for 4: triclinic, space group P-1, a?=?9.3425(19), b?=?11.432(2), c?=?12.703(3)?Å, α?=?65.28(3), β?=?73.80(3), γ?=?86.86(3)°, V?=?1180.6(4)?ų, Z?=?1, D _c?=?1.7794?Mg?m^?3. The fluorescence emission spectra of compounds 1 to 4 are also reported.     

New Cadinane‐Type Sesquiterpenes from the Roots of Taiwania cryptomerioides Hayata

Six new cadinane‐type sesquiterpenes, (1β,4β,5α,10α)‐1,4‐epoxymuurolan‐5‐ol ( 1 ), (4α,10β)‐4,10‐dihydroxycadin‐1(6)‐en‐5‐one ( 2 ), (2β,3α,4β,6β)‐2,3‐dihydroxycadin‐1(10)‐en‐5‐one ( 3 ), (2β,3α)‐α‐corocalene‐2,3‐diol ( 4 ), (7S)‐α‐calacoren‐14‐ol ( 5 ), and (8β,9β,10β)‐8,9‐epoxycalamenene‐3,10‐diol ( 6 ) together with one known compound, (8β,9β,10β)‐8,9‐epoxycalamenen‐10‐ol ( 7 ), were isolated from the roots of Taiwania cryptomerioides. The structures of the new constituents were essentially elucidated by spectral evidence.     

Transition Metal Halide Salts and Complexes of 2-Aminopyrimidine: Cobalt(II) and Nickel(II) compounds,Crystal Structures of Bis(2-Aminopyrimidinium)MX4 [M = Co,Ni; X = Cl,Br] and 2-Aminopyrimidinium(+2) [NiBr2(H2O)4]Br2

The reaction of MX₂ (M = Co(II), Ni(II); X = Cl, Br) with 2-aminopyrimidine in aqueous acid yields compounds [(2-apmH)₂MX₄], (2-apmH)₂[MX₄], or (2-apmH₂) [MX₂(H₂O)₄]X₂ (2-apmH = 2-aminopyrimidinium; 2-apmH₂ = 2-aminopyrimidinium(2+)). All compounds have been characterized by single crystal X-ray diffraction. The compounds [(2-apmH)₂MX₄] with M = Co, X = Cl (1); M = Ni, X = Cl (3); and M = Ni, X = Br (4) are isomorphous and crystallize as nearly square planar MX₄ units with the 2-apmH cations coordinated in the axial sites through the unprotonated ring nitrogen. (2-ApmH)₂[CoBr₄] (2) crystallizes as the salt with a nearly tetrahedral CuBr₄ ^2- anion. (2-ApmH₂)[NiBr₂(H₂O)₄]Br₂ (5) forms as a cocrystal of the neutral, six-coordinate nickel complex and (2-ampH₂)Br₂, stabilized by extensive hydrogen bonding. Crystal data (1): monoclinic, P2₁/c, a = 7.540(4), b = 12.954(4), c = 7.277(3) Å, β = 110.09(6), V = 667.4(5) ų, Z = 2, D_calc = 1.955 Mg/m³, μ = 2.079 mm^-1, R = 0.0501 for [|I|≥2(I)]. For (2): triclinic, P-1, a = 7.720(2), b = 7.916(2), c = 14.797(3) Å, α = 97.264(3), β = 104.788(3), γ = 105.171(3)°, V = 825.3(3) ų, Z = 2, D_calc = 2.296 Mg/m³, μ = 10.715 mm^-1, R = 0.0308 for [|I|≥2(I)]. For (3): monoclinic, P2₁/c, a = 7.595(3), b = 12.891(4), c = 7.204(3) Å, β = 111.07(3)°, V = 658.2 ų, Z = 2, D_calc = 1.982 Mg/m³, μ = 2.279 mm^-1, R = 0.0552 for [|I|≥2(I)]. For (4): monoclinic, P2₁/c, a = 7.840(2), b = 13.358(4), c = 7.518(2) Å, β = 110.923(3)°, V = 938.6(3) ų, Z = 2, D_calc = 2.577 Mg/m³, μ = 12.18 mm^-1, R = 0.0280 for [|I|≥2(I)]. For (5): orthorhombic, Pnma, a = 16.776(6), b = 11.943(4), c = 7.079(3) Å, V = 1418.2(9) ų, Z = 4, D_calc = 2.564 Mg/m³, μ = 12.639 mm^-1, R = 0.0381 for [|I|≥2σ(I)].     

Synthetic studies directed toward the pseurotins. Part II. Synthesis of related highly functionalized furan-3(2H)-ones

The synthesis of 2,2-bis(hydroxymethyl)-4-methyl-5-phenylfuran-3(2H)-one ( 9 ), 5-[(1S,2S,Z)-1,2-(ethylidenedioxy)hex-3-enyl]-2,2-bis(hydroxymethyl)-4-methylfuran-3(2H)-one ( 24 ), and 5-[(1S,2S,Z)-1,2-(ethylidenedioxy)hex-3-enyl]-2-(hydroxymethyl)-4-methylfuran-3(2H)-one ( 28 ), which represent more advanced, suitably functionalized intermediates for the synthesis of pseurotin A ( 1 ), a secondary metabolite of Pseudeurotium ovalis STOLK , is described.     

SYNTHESIS OF ANELLATED ANHYDROPYRANOSES ON THE BASIS OF 1,6-ANHYDRO-3-DEOXY-4-METHYLSULFANYL-3-[(METHYLSULFANYL)METHYLENE]-β-D-ERYTHRO-HEXOPYRANOS-2-ULOSE

(Z)-1,6-Anhydro-3-deoxy-4-methylsulfanyl-3-[(methylsulfanyl)methylene]-β-D-erythro-hexopyranos-2-ulose (1) reacted with diethyl malonate, 1,3-diketones, N-aryl-3-oxobutyramides and dialkyl 3-oxoglutarate, respectively, in the presence of potassium carbonate and crown ether to yield diethyl 2-(1,6-anhydro-4-methylsulfanyl—D-arabino-hex-2-ulopyranos-3-ylmethylene) malonate (2), 1-{(1R,2S,8S,9R)-2-hydroxy-4-methyl-8-methylthio-3,11,12- trioxatricyclo7.2.1.0^2,7dodeca-4,6-dien-5-yl} ethanone (3), (1R,2S,12S,13R)-2-hydroxy-12-methylthio-3,15,16-trioxatetracyclo[11.2.1. 0^2,11. 0^4,9] hexadeca- 4(9),10-dien-8-one (4), (1R,8S,9R)-5-acetyl-3-aryl-8-methylthio-11,12-dioxa- 3-azatricyclo-[7.2.1.0^2,7]dodeca-2(7),5-dien-4-ones (5,6) and dialkyl (1R,8S,-9R)-4-hydroxy-8-methylthio-11,12-dioxatricyclo[7.2.1.0^2,7]dodeca-2(7),3,5-triene-3,5-dicarboxylates (7,8), respectively.     

Isolation from the Mediterranean Stolonifern Coral Sarcodictyon roseum of Sarcodictyin C,D, E,and F,novel diterpenodic alcohols esterified by (E)- or (Z)-N(1)-methylurocanic acid. Failure of the carbon-skeleton type as a classification criterion

It is shown here that the stoloniferan coral Sarcodictyon roseum of east Pyrenean waters contains four novel diterpenoids, sarcodictyin C ((?) -3 ), D ((?) -4 ), E ((+)- 5 ), F ((+)- 6 ), which are related to sarcodictyin A ( = (?)-(4R,4aR,7R,10S,11S,12aR,1Z,5E,8Z-7,10-epoxy-3,4,4a,7,10,11,12,12a-octahydro-7-hydroxy-6-(methyoxycarbonyl)-1,10-dimethyl-4-(1-methylethyl)-benzocyclodecen-11-yl (E)-N¹-methylyrocanate; ((?)? 1 ), previously isolated from the same coral. Sarcodictyin C ((?) -3 ) and D ((?) -4 ) and the 3α-hydroxy and 3α-acetoxy derivatives of (?) -1 ), sarcodictyin E ((+) -5 ) is the (Z)-urocanate isomer of (?) -3 ), and sarcodictyin F ((+) -6 ) is the 1α-hydroxy-2-ene isomer of (?) -3 . In all cases, the nine-membered ring is locked, and the molecule stabilized, by the urocanic appendage; when this is removed in MeOH/KOH, the C(11)–O^? function is free to attack at C(5), and retro-condensations then lead to the ring-contracted butenolides 11 (from (?) -3 ) or 10 (from(?) -1 ) with extrusion of the hydroxyfuran nucleus (Scheme 3). Under the same conditions, with (?) -3 , the C(3)-O^? group competitively attacks at C(5), the hydroxyfuran nucleus is expelled, and aldehyde 14 is formed. Peculiarly, in the reaction of (?) -3 with MeOD/KOD, the ring-contracted butenolide 17 contains D at the 4′-ax position. The sarcodictyins are unique in these chemical properties, not shared by the cladiellanes which have the same C-skeleton.     

Artabotryols A – E,New Lanostane Triterpenes from the Seeds of Artabotrys odoratissimus

Six new lanostane triterpenes, artabotryols A, B, C1, C2, D, and E ( 1, 2, 3a, 3b, 4 , and 5 , resp.) have been isolated from the seeds of Artabotrys odoratissimus (Annonaceae). Their structures have been established as (3α,22S,25R)‐3‐hydroxy‐22,26‐epoxylanost‐8‐en‐26‐one ( 1 ), (3α,22S,25R)‐22,26‐epoxylanost‐8‐ene‐3,26‐diol ( 2 ), (3α,22S,25R,26R)‐26‐methoxy‐22,26‐epoxylanost‐8‐en‐3‐ol ( 3a ), (3α,22S,25R, 26S)‐26‐methoxy‐22,26‐epoxylanost‐8‐en‐3‐ol ( 3b ), (3α,22S,25R)‐3,22‐dihydroxylanost‐8‐en‐26‐oic acid ( 4 ) and (3α,7α,11α,22S,25R)‐3,7,11‐trihydroxy‐22,26‐epoxylanost‐8‐en‐26‐one ( 5 ) by spectroscopic studies and chemical correlations.     

Four New Pregnane Steroids from Aglaia abbreviata and Their Cytotoxic Activities

Four new pregnane steroids, aglaiasterols A–D ( 1 – 4 ), have been isolated from the EtOH extract of stems of Aglaia abbreviata. They were identified as (3α,5α,17Z)‐3‐hydroxypregn‐17‐en‐16‐one ( 1 ), (3β,5α,17E)‐3‐hydroxypregn‐17‐en‐16‐one ( 2 ), (3β,5α,17Z)‐3‐hydroxypregn‐17‐en‐16‐one ( 3 ), and (3α,5α,20S*)‐3‐hydroxy‐16‐oxopregnan‐20‐yl acetate ( 4 ) on the basis of spectroscopic methods, including 1D‐ and 2D‐NMR techniques. Compounds 1 – 4 were evaluated for their cytotoxic activities against K562 (human leukemia), MCF‐7 (human breast cancer), and KB (human oral epithelium cancer) cells, and drug‐resistant cells of K562/A02, MCF‐7/ADM, and KB/VCR. These isolates showed weak to moderate inhibitory effects on the growth of the tested cell lines.