Three Escin‐Like Triterpene Saponins: Assamicins VI,VII, and VIII from the Seeds of Aesculus assamica Griff

Three new escin‐like triterpene saponins, assamicins VI ( 1 ), VII ( 2 ), and VIII ( 3 ), were isolated from the seeds of A. assamica, together with a known saponin, isoescin Ib ( 4 ). Their structures were established as 28‐O‐acetyl‐21‐O‐(3,4‐di‐O‐angeloyl‐6‐deoxy‐β‐glucopyranosyl)‐3‐O‐{O‐β‐glucopyranosyl‐(1→2)‐O‐[β‐glucopyranosyl‐(1→4)]‐β‐glucopyranuronosyl}protoaescigenin ( 1 ), 21‐O‐angeloyl‐3‐O‐{O‐α‐rhamnopyranosyl‐(1→2)‐O‐[β‐glucopyranosyl‐(1→3)]‐β‐glucopyranuronosyl}protoaescigenin ( 2 ), and 21‐O‐angeloyl‐3‐O‐{O‐[β‐glucopyranosyl‐(1→3)]‐β‐glucopyranuronosyl}protoaescigenin ( 3 ) on the basis of spectroscopic analysis (protoaescigenin=(3β,4β,16α,21β,22α)‐olean‐12‐ene‐3,16,21,22,23,28‐hexol; angelic acid=(2Z)‐2‐methylbut‐2‐enoic acid).     

Chemical Constituents from the Roots of Schnabelia tetradonta

The new rearranged‐abietane diterpene 1 , the four new triterpenoids 2 – 5 , and the new aminoethylphenyl oligoglycoside 6 , besides 19 known compounds, were isolated from the roots of Schnabelia tetradonta, a Chinese endemic herb. The structures of the new compounds were elucidated on the basis of spectroscopic evidence as 12,17‐epoxy‐11,14,16‐trihydroxy‐17(15→16)‐abeo‐abieta‐8,11,13,15‐tetraen‐7‐one ( 1 ), 21β‐(β‐D ‐glucopyranosyloxy)‐2α,3α‐dihydroxyolean‐12‐en‐28‐oic acid ( 2 ), 2β,3β,16β‐trihydroxy‐15‐oxo‐28‐norolean‐12‐en‐23‐oic acid ( 3 ), 3β‐[(4‐O‐acetyl‐β‐D ‐glucopyranuronosyl)oxy]‐2β,16β‐dihydroxy‐28‐norolean‐15‐oxo‐12‐en‐23‐oic acid ( 4 ), 3β‐[(4‐O‐acetyl‐6‐O‐methyl‐β‐D ‐glucopyranuronosyl)oxy]‐2β,16β‐dihydroxy‐15‐oxo‐28‐norolean‐12‐en‐23‐oic acid ( 5 ), and 4‐[2‐(acetylamino)ethyl]phenyl O‐6‐O‐[(Z)‐p‐methoxycinnamoyl]‐β‐D ‐glucopyranosyl‐(1→2)]‐O‐[β‐D ‐glucopyranosyl‐(1→3)]‐4‐O‐acetyl‐α‐L ‐rhamnopyranoside ( 6 ), respectively.     

Synthesis of 32‐phenyl‐substituted methyl E/Z‐pyropheophorbide‐a's from methyl E/Z‐pyropehophorbide‐a 131‐ketoximes

Methyl E/Z‐pyropheophorbide‐a 13¹‐ketoximes 2a,b and their O‐acetyl derivatives 3a,b were oxidized with osmium(VIII) oxide to give aldehydes 4a,b and 5a,b , respectively. The Wittig reactions of the aldehyde chlorines 4a,b and 5a,b with benzyltriphenylphosphonium chloride were performed to form the corresponding methyl (3¹E/Z,13¹E/Z)‐3²‐phenylpyropheophorbide‐a 13¹‐ketoximes 6aa‐bb and their O‐acetyl derivatives 7aa‐bb ; hydrolysis of these ketoximes 6aa,ba and 6ab,bb in formic acid produced methyl (E/Z)‐3²‐phenylpyropheophorbide‐a's 8a,b .     

Polar Metabolites of the Tropical Green Seaweed Caulerpa taxifolia Which Is Spreading in the Mediterranean Sea: Glycoglycerolipids and Stable Enols (α\=Keto Esters)

Examination of the polar components of the green seaweed Caulerpa taxifolia (Vahl ) C. Agardh , which is heavily spreading in the northeastern Mediterranean, led to two families of compounds. The new (2R)-3-O-β-D -galactopyranosyl-1-O-[(7Z,10Z,13Z)-hexadeca-7,10,13-trienoyl]-2-O-[(9Z,12Z,15Z)-octadeca-1,12,15-trienoyl]-sn-glycerol ( 2 ) was isolated in low abundance, like the analogues 1 and 3 already known from freshwater cyanobacteria. The acyl positions in 1 – 3 were determined by enzymatic methods and the absolute configuration from the O-galactosylglycerol obtained upon alcaline methanolysis. More abundant were the (4-hydroxyphenyl)- and (3,4-dihydroxyphenyl)pyruvic acid methyl esters, occurring in the enol (Z) forms 13a and 14a accompanied by very minor (E) forms 13b and 14b . The latter became predominant on UV irradiation of 13a or 14a , allowing the determination of the C=C configuration of these isolatable, stable enols from ¹H,¹³C NMR couplings (larger H−C(3)/C(1) coupling constant in the (E) than in the (Z) isomer). Contrary to literature implications, the O-galactosylglycerolipids 1 – 3 lack any cholinergic or histaminergic activity; similarly, enols (= α-keto esters) 13 and 14 or terpenoids of this seaweed were also devoid of such biological activities (see Table).     

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.     

Palmitoleate (=(9Z)‐Hexadeca‐9‐enoate) Esters of Oleanane Triterpenoids from the Golden Flowers of Tagetes erecta: Isolation and Autoxidation Products

Six oleanane‐type triterpenoid esters were isolated from the golden flowers of Tagetes erecta. Spectral studies characterized their structures as 3‐O‐[(9Z)‐hexadec‐9‐enoyl]erythrodiol ( 1 ), 11α,12α:13β,28‐diepoxyoleanan‐3β‐yl (9Z)‐hexadec‐9‐enoate ( 2 ), 13β,28‐epoxyolean‐11‐en‐3β‐yl (9Z)‐hexadec‐9‐enoate ( 3 ), 28‐hydroxy‐11‐oxoolean‐12‐en‐3β‐yl (9Z)‐hexadec‐9‐enoate ( 4 ), 3‐O‐[(9Z‐hexadec‐9‐enoyl]‐β‐amyrin ( 5 ), and 11‐oxoolean‐12‐en‐3β‐yl (9Z)‐hexadec‐9‐enoate ( 6 ). Compounds 1 – 4 and 6 are new natural products, while the known 5 was isolated for the first time from the genus Tagetes, from which only one triterpenoid has earlier been obtained. Aerial oxidation (autoxidation) converted amyrin 1 into 2 – 4 and transformed amyrin 5 into 6 . The configuration of 1 – 6 and an autoxidation mechanism (Scheme) involving the formation of the intermediate 11α‐hydroxyolean‐12‐ene derivatives 1b and 5b on thermal decomposition of the labile 11α‐OOH derivatives 1a and 5a , respectively, under neutral conditions are discussed. For the first time, the reactivity of the allylic H? C(11) bond of triterpenoids of type 1 and 5 toward aerial oxidation was observed. The long‐chain ester group at C(3) of 1 and 5 may be responsible for their labile nature, as β‐amyrin ( 7 ), erythrodiol ( 8 ), and ursolic acid were found to be inert toward autoxidation.     

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.     

Acylglycerols (=Glycerides) from the Glandular Trichome Exudate on the Leaves of Paulownia tomentosa

Chemical investigations of the glandular trichome exudates on the leaves of Paulownia tomentosa (Scrophulariaceae) led to the identification of the thirty acylglycerols (=glycerides) 1 – 30 , including five known ones ( 2, 3, 6, 9 , and 15 ) (Fig. 1). Spectroscopic analysis combined with GC/MS studies of the glycerides and the liberated fatty acids, in the form of trimethylsilyl ether derivatives and trimethylsilylated methyl esters, respectively, established that the constituents belonged to 1,3‐di‐O‐acetyl‐2‐O‐(fatty acyl)glycerols, 1‐O‐acetyl‐2‐O‐(fatty acyl)‐sn‐glycerols, and 2‐O‐(fatty acyl)glycerols, wherein the fatty acyl moiety was either an eicosanoyl or an octadecanoyl group bearing OH and/or AcO groups at the 3‐, 3,6‐, 3,7‐, 3,8‐, or 3,9‐positions. The 1‐O‐acetyl‐2‐O‐[(3R,6S)‐3‐(acetyloxy)‐6‐hydroxyeicosanoyl]‐sn‐glycerol ( 12 ; 20% of the total glycerides), 2‐O‐[(3R,8R)‐3,8‐bis(acetyloxy)eicosanoyl]glycerol ( 17 ; 14%), 2‐O‐[(3R,9R)‐3,9‐bis(acetyloxy)eicosanoyl]glycerol ( 18 ; 12%), and 2‐O‐[(3R)‐3‐(acetyloxy)eicosanoyl]glycerol ( 10 ; 12%) were relatively abundant constituents. The configurations of the stereogenic centers of the fatty acyl moieties were determined by ¹H‐NMR analysis of the monoesters obtained from (R)‐ and (S)‐2‐(naphthalen‐2‐yl)‐2‐methoxyacetic acid ((R)‐ and (S)‐2NMA? OH and the hydroxy‐substituted fatty acid methyl esters (Fig. 2). The configuration at C(2) of the glycerol moiety of the 1‐O‐acetyl‐2‐O‐(fatty acyl)glycerols was determined to be (2S) by chemical conversion of, e.g., G‐2 (= 2 / 3 1 : 10) to (+)‐3‐O‐[tert‐butyl)diphenylsilyl]‐sn glycerol of known absolute configuration.     

Diterpene Glycosides from the Dry Fronds of Conyza japonica

Phytochemical investigation of the 95% EtOH extract of the dry fronds of Conyza japonica (Thunb .) Less. resulted in the isolation of three new labdane diterpene glycosides, (3β,13S)‐13‐O‐α‐L ‐rhamnopyranosyllabda‐8(17),14‐dien‐3‐yl α‐L ‐rhamnopyranoside ( 1 ), (3β,13S)‐13‐O‐α‐L ‐rhamnopyranosyllabda‐8(17),14‐diene‐3‐yl 2‐O‐acetyl‐α‐L ‐rhamnopyranoside ( 2 ), and (3β,13S)‐13‐O‐α‐L ‐rhamnopyranosylabda‐8(17),14‐dien‐3‐yl 6‐O‐acetyl‐β‐D ‐glucopyranosyl‐(1→2)‐α‐L ‐rhamnopyranoside ( 3 ), together with their aglycone, (13S)‐labda‐8(17),14‐diene‐3,13‐diol ( 4 ). Their structures were characterized by spectroscopic analyses and chemical correlations, including 1D‐ and 2D‐NMR, and HR‐ESI‐MS. Furthermore, compounds 1 – 3 appeared to be promising as active agents against the tested pathogen fungi and oral pathogens as they possessed moderate cytotoxic properties.     

Sesquiterpenoids from Ligularia dentata

Five new compounds were isolated from the roots of Ligularia dentata, including four bisabolane‐type sesquiterpenoids, 1 – 4 , as well a new eudesmane, 5 . The previously isolated 3α,6α,9‐tris(angeloyloxy)‐2α,4β‐dihydroxy‐7,11‐epoxybisabol‐10(15)‐en‐5‐one ( 6 ), when left as an oil in a refrigerator over nine months, gave rise to a mixture of two positional isomers, 7 and 8 . Their formation is rationalized by means of epoxide ring opening and shift of an angeloyl (Ang) group. The structures of compounds 1 – 5, 7 , and 8 were established by in‐depth spectroscopic (UV, CD, IR, 1D‐ and 2D‐NMR) as well as mass‐spectrometric methods.     

Antitumor Sesquiterpenes from Euonymus nanoides

The isolation, structure elucidation, and antitumor activity of four new sesquiterpene polyol esters, i.e., of 6α,13‐bis(acetyloxy)‐9β‐(cinnamoyloxy)‐1β‐(furan‐3‐ylcarbonyl)oxy]‐4α‐hydroxy‐β‐dihydroagarofuran ( 1 ), 13‐(acetyloxy)‐9β‐(benzoyloxy)‐4α‐hydroxy‐1β,6α‐bis[(2‐methylbutanoyl)oxy]‐β‐dihydroagarofuran ( 2 ), 1β,6α,13‐ tri(acetyloxy)‐9β‐(cinnamoyloxy)‐4α‐hydroxy‐β‐dihydroagarofuran ( 3 ), and 6α,13‐bis(acetyloxy)‐9β‐(benzoyloxy)‐4α‐hydroxy‐1β‐[(2‐methylbutanoyl)oxy]‐β‐dihydroagarofuran ( 4 ), and of five known sesquiterpene polyol esters 5 – 9 from the seed oil of Euonymus nanoides Loes. are reported (β‐dihydroagarofuran=octahydro‐2,2,5a,9‐tetramethyl‐2H‐3,9a‐methano‐1‐benzoxepin).     

Triterpene Saponins from Four Species of the Polygalaceae Family

Twelve triterpene saponins were isolated by successive MPLC over silica gel from four species of Polygalaceae: From Polygala ruwenzoriensis, five new saponins 1 – 5 of which 1 – 4 as two pairs of (E)/(Z)‐isomers, together with the four known compounds tenuifoline, (E)‐ and (Z)‐senegasaponin b, (E)‐ and (Z)‐senegin II, and polygalasaponin XXVIII, from the genus Carpolobia, one new saponin 6 from C. alba and the known arilloside ( 11 ) from C. lutea, and another new triterpene glycoside 7 from Polygala arenaria. Their structures were established mainly by 600‐MHz 2D‐NMR techniques (¹H,¹H‐COSY, TOCSY, NOESY, HSQC, HMBC) as 3‐O‐(β‐D ‐glucopyranosyl)presenegenin 28‐{O‐α‐L ‐arabinopyranosyl‐(1 → 4)‐O‐β‐D ‐xylopyranosyl‐(1 → 4)‐O‐α‐L ‐rhamnopyranosyl‐(1 → 2)‐4‐O‐[(E)‐4‐methoxycinnamoyl]‐β‐D ‐fucopyranosyl} ester ( 1 ) and its (Z)‐isomer 2 , 3‐O‐(β‐D ‐glucopyranosyl)presenegenin 28‐{O‐α‐L ‐arabinopyranosyl‐(1 → 4)‐O‐β‐D ‐xylopyranosyl‐(1 → 4)‐O‐α‐L ‐rhamnopyranosyl‐(1 → 2)‐4‐O‐[(E)‐3,4‐dimethoxycinnamoyl]‐β‐D ‐fucopyranosyl} ester ( 3 ) and its (Z)‐isomer 4 , 3‐O‐(β‐D ‐glucopyranosyl)presenegenin 28‐[O‐β‐D ‐galactopyranosyl‐(1 → 4)‐O‐β‐D ‐xylopyranosyl‐(1 → 4)‐O‐α‐L ‐rhamnopyranosyl‐(1 → 2)‐β‐D ‐fucopyranosyl] ester ( 5 ), 3‐O‐(β‐D ‐glucopyranosyl)presenegenin 28‐{O‐α‐L ‐arabinopyranosyl‐(1 → 3)‐O‐[β‐D ‐galactopyranosyl‐(1 → 4)]‐O‐β‐D ‐xylopyranosyl‐(1 → 4)‐O‐α‐L ‐rhamnopyranosyl‐(1 → 2)‐O‐[β‐D ‐apiofuranosyl‐(1 → 3)]‐4‐O‐acetyl‐β‐D ‐fucopyranosyl} ester ( 6 ), and 3‐O‐(β‐D ‐glucopyranosyl)presenegenin 28‐{O‐β‐D ‐galactopyranosyl‐(1 → 4)‐O‐[β‐D ‐glucopyranosyl‐(1 → 3)]‐O‐β‐D ‐xylopyranosyl‐(1 → 4)‐O‐α‐L ‐rhamnopyranosyl‐(1 → 2)‐β‐D ‐fucopyranosyl} ester ( 7 ) (presenegenin = (2β,3β,4α)‐2,3,27‐trihydroxyolean‐12‐ene‐23,28‐dioic acid).     

New Cytotoxic Myrsinane‐Type Diterpenes from Euphorbia prolifera

Four new myrsinol diterpenes, proliferins A–D ( 1 – 4 , resp.) were isolated from the EtOH extracts of the roots of Euphorbia prolifera, along with four known compounds, euphorprolitherin B ( 5 ), euphorprolitherin D ( 6 ), SPr5 ( 7 ), and 14‐desoxo‐3‐O‐propionyl‐5,15‐di‐O‐acetyl‐7‐O‐nicotinoylmyrsinol‐14β‐acetate ( 8 ). Their structures were established on the basis of spectroscopic methods, including HR‐ESI‐MS, and 1D‐ and 2D‐NMR techniques. The cytotoxicity of compounds 1, 3 , and 4 against cancer cells was evaluated, with compound 1 being active against A2780 cancer cells.     

Polyprenylated Phloroglucinol Derivatives from Hypericum sampsonii

Six new prenylated phloroglucinol derivatives, hypersampsones A–F ( 1 – 6 ), were isolated from the aerial part of Hypericum sampsonii, together with 2,4,6‐trihydroxybenzophenone, 2,4,6‐trihydroxybenzophenone 4‐O‐geranyl ether, 2,4,6‐trihydroxybenzophenone 3‐C‐geranyl ether, sampsoniones D and H. Their structures were elucidated by spectroscopic methods, mainly 1D‐ and 2D‐NMR spectroscopy and mass spectrometry.     

Synthesis and Structure of O,O‐Diethyl N‐[(trans‐4‐Aryl‐5,5‐dimethyl‐2‐oxido‐2λ5‐1,3,2‐dioxaphosphorinan‐2‐yl)methyl]phosphoramidothioates

A study on the synthesis of the novel N‐(cyclic phosphonate)‐substituted phosphoramidothioates, i.e., O,O‐diethyl N‐[(trans‐4‐aryl‐5,5‐dimethyl‐2‐oxido‐2λ⁵‐1,3,2‐dioxaphosphorinan‐2‐yl)methyl]phosphoramidothioates 4a – l , from O,O‐diethyl phosphoramidothioate ( 1 ), a benzaldehyde or ketone 2 , and a 1,3,2‐dioxaphosphorinane 2‐oxide 3 was carried out (Scheme 1 and Table 1). Some of their stereoisomers were isolated, and their structure was established. The presence of acetyl chloride was essential for this reaction and accelerated the process of intramolecular dehydration of intermediate 5 forming the corresponding Schiff base 7 (Scheme 2).     

Conversion of substituted 5‐aryloxypyrazolecarbaldehydes into reduced 3,4′‐bipyrazoles: synthesis and characterization,and the structures of four precursors and two products,and their supramolecular assembly in zero,one and two dimensions

The reaction of 5‐chloro‐3‐methyl‐1‐phenyl‐1H‐pyrazole‐4‐carbaldehyde with phenols under basic conditions yields the corresponding 5‐aryloxy derivatives; the subsequent reaction of these carbaldehydes with substituted acetophenones yields the corresponding chalcones, which in turn undergo cyclocondensation reactions with hydrazine in the presence of acetic acid to form N‐acetylated reduced bipyrazoles. Structures are reported for three 5‐aryloxycarbaldehydes and the 5‐piperidino analogue, and for two reduced bipyrazole products. 5‐(2‐Chlorophenoxy)‐3‐methyl‐1‐phenyl‐1H‐pyrazole‐4‐carbaldehyde, C₁₇H₁₃ClN₂O₂, (II), which crystallizes with Z′ = 2 in the space group P, exhibits orientational disorder of the carbaldehyde group in each of the two independent molecules. Each of 3‐methyl‐5‐(4‐nitrophenoxy)‐1‐phenyl‐1H‐pyrazole‐4‐carbaldehyde, C₁₇H₁₃N₃O₄, (IV), 3‐methyl‐5‐(naphthalen‐2‐yloxy)‐1‐phenyl‐1H‐pyrazole‐4‐carbaldehyde, C₂₁H₁₆N₂O₂, (V), and 3‐methyl‐1‐phenyl‐5‐(piperidin‐1‐yl)‐1H‐pyrazole‐4‐carbaldehyde, C₁₆H₁₉N₃O, (VI), (3RS)‐2‐acetyl‐5‐(4‐azidophenyl)‐5′‐(2‐chlorophenoxy)‐3′‐methyl‐1′‐phenyl‐3,4‐dihydro‐1′H,2H‐[3,4′‐bipyrazole] C₂₇H₂₂ClN₇O₂, (IX) and (3RS)‐2‐acetyl‐5‐(4‐azidophenyl)‐3′‐methyl‐5′‐(naphthalen‐2‐yloxy)‐1′‐phenyl‐3,4‐dihydro‐1′H,2H‐[3,4′‐bipyrazole] C₃₁H₂₅N₇O₂, (X), has Z′ = 1, and each is fully ordered. The new compounds have all been fully characterized by analysis, namely IR spectroscopy, ¹H and ¹³C NMR spectroscopy, and mass spectrometry. In each of (II), (V) and (IX), the molecules are linked into ribbons, generated respectively by combinations of C—H…N, C—H…π and C—Cl…π interactions in (II), C—H…O and C—H…π hydrogen bonds in (V), and C—H…N and C—H…O hydrogen bonds in (IX). The molecules of compounds (IV) and (IX) are both linked into sheets, by multiple C—H…O and C—H…π hydrogen bonds in (IV), and by two C—H…π hydrogen bonds in (IX). A single C—H…N hydrogen bond links the molecules of (X) into centrosymmetric dimers. Comparisons are made with the structures of some related compounds.     

Z/E‐Isomerism of 3‐[4‐(dimethylamino)phenyl]‐2‐(2,4,6‐tribromophenyl)acrylonitrile: crystal structures and secondary intermolecular interactions

The Z and E isomers of 3‐[4‐(dimethylamino)phenyl]‐2‐(2,4,6‐tribromophenyl)acrylonitrile, C₁₇H₁₃Br₃N₂, ( 1 ), were obtained simultaneously by a Knoevenagel condensation between 4‐(dimethylamino)benzaldehyde and 2‐(2,4,6‐tribromophenyl)acetonitrile, and were investigated by X‐ray diffraction and density functional theory (DFT) quantum‐chemical calculations. The (Z)‐( 1 ) isomer is monoclinic (space group P2₁/n, Z′ = 1), whereas the (E)‐( 1 ) isomer is triclinic (space group P, Z′ = 2). The two crystallographically‐independent molecules of (E)‐( 1 ) adopt similar geometries. The corresponding bond lengths and angles in the two isomers of ( 1 ) are very similar. The difference in the calculated total energies of isolated molecules of (Z)‐( 1 ) and (E)‐( 1 ) with DFT‐optimized geometries is ∼4.47 kJ mol⁻¹, with the minimum value corresponding to the Z isomer. The crystal structure of (Z)‐( 1 ) reveals strong intermolecular nonvalent Br…N [3.100 (2) and 3.216 (3) Å] interactions which link the molecules into layers parallel to (10). In contrast, molecules of (E)‐( 1 ) in the crystal are bound to each other by strong nonvalent Br…Br [3.5556 (10) Å] and weak Br…N [3.433 (4) Å] interactions, forming chains propagating along [110]. The crystal packing of (Z)‐( 1 ) is denser than that of (E)‐( 1 ), implying that the crystal structure realized for (Z)‐( 1 ) is more stable than that for (E)‐( 1 ).     

Four New Nor‐Diterpenoid Alkaloids from Aconitum brachypodum

Four new C₁₉‐nor‐diterpenoid alkaloids, named brachyaconitines A–D ( 1 – 4 ), were isolated from the roots of Aconitum brachypodum Diels. Their structures were elucidated as 3‐O‐acetyl‐20‐deethyl‐20‐formylaconitine ( 1 ), 3‐O‐acetyl‐19,20‐didehydro‐20‐deethylaconitine ( 2 ), 3‐O‐acetyl‐8‐de(acetyloxy)‐7,8,17,20‐tetradehydro‐20‐deethyl‐7,17‐secoaconitine ( 3 ), and 1‐O‐methylflavaconitine ( 4 ) by means of MS, IR, 1D‐ and 2D‐NMR analyses. The structure of compound 1 was confirmed by an X‐ray diffraction experiment.     

Hydrogen‐Bonding in Cyclic 2‐(3‐Oxo‐3‐phenylpropyl)‐Substituted 1,3‐Diketones: 17O‐NMR Spectra and X‐Ray Structure Determination

Structures of cyclic 2‐(3‐oxo‐3‐phenylpropyl)‐substituted 1,3‐diketones 4a – c were determined by ¹⁷O‐NMR spectroscopy and X‐ray crystallography. In CDCl₃ solution, compounds 4a – c form an eight‐membered‐ring with intramolecular H‐bonding between the enolic OH and the carbonyl O(11)‐atom of the phenylpropyl group, as demonstrated by increased shielding of specifically labeled 4a – c in the ¹⁷O‐NMR spectra (Δδ(¹⁷O(11))=36 ppm). In solid state, intermolecular H‐bonding was observed instead of intramolecular H‐bonding, as evidenced by the X‐ray crystal‐structure analysis of compound 4b . Crystals of compound 4b at 293 K are monoclinic with a=11.7927 (12) Å, b=13.6230 (14) Å, c=9.8900 (10) Å, β=107.192 (2)°, and the space group is P2₁/c with Z=4 (refinement to R=0.0557 on 2154 independent reflections).     

Lanostanoids Isolated from Ganoderma lucidum Mycelium Cultured by Submerged Fermentation

Three new lanostane triterpene acids, 3‐O‐acetylganoderic acid B ( 1 ), 8β,9α‐dihydroganoderic acid C ( 3 ), and 3‐O‐acetylganoderic acid K ( 4 ), as well as two new lanostane triterpene acid ethyl esters, ethyl 3‐O‐acetylganoderate B ( 2 ) and ethyl ganoderate J ( 5 ), were isolated and characterized from Ganoderma lucidum mycelia which was cultured by submerged fermentation method. Their structures were elucidated on the basis of spectroscopic methods. In addition, the identification of two known lanostane triterpene acid methyl esters, methyl O‐acetyl ganoderate C and methyl 3,7,11,15,23‐pentaoxo‐lanost‐8‐en‐26‐oate were identified by comparison of the NMR data with those reported in the literature.