Flavone Glycosides from Strobilanthes Formosanus

Two new flavone glycosides, 3′‐hydroxy‐5,7‐dimethoxyflavone 4′‐O‐β‐D‐apiofuranoside ( 1 ), and 5,7‐dimethoxyflavone 4′‐O‐[β‐D‐apiofuranosyl(1→5)‐ β‐D‐glucopyranoside] ( 2 ) along with four known compounds, 4′‐hydroxy‐5,7‐dimethoxyflavone ( 3 ), 2,6‐dimethoxy‐1,4‐benzoquinone ( 4 ), lupeol ( 5 ) and betulin ( 6 ) were isolated from the stem and roots of Strobilanthes formosanus. Their structures were elucidated on the basis of their spectroscopic evidence.     

Cytotoxic Activity of Capnellene‐8β, 10α‐Diol Derivatives from a Taiwanese Soft Coral Capnella sp.

The sesquiterpene capnellene‐8β, 10α‐diol ( 1 ) was isolated from non‐polar extract of the soft coral Capnella sp. Ten acylation products of capnellene‐8β, 10α‐diol were prepared: 10α‐hydroxy‐8β‐O‐benzoylcapnellene ( 2 ), 10α‐hydroxy‐8β‐O‐p‐toluoylcapnellene ( 3 ), 10α‐hydroxy‐8β‐O‐4‐chlorobenzoyl‐capnellene ( 4 ), 10α‐hydroxy‐8β‐O‐2‐furoylcapnellene ( 5 ), 10α‐hydroxy‐8β‐O‐2‐thiophenoylcapnellene ( 6 ), 10α‐hydroxy‐8β‐O‐4‐fluorobenzoylcapnellene ( 7 ), 10α‐hydroxy‐8β‐O‐4‐propylbenzoylcapnellene ( 8 ), 10α‐hydroxy‐8β‐O‐cinnamoylcapnellene ( 9 ), 10α‐hydroxy‐8β‐O‐4‐nitrobenzoylcapnellene ( 10 ), and 10α‐hydroxy‐8β‐O‐4‐anisoylcapnellene ( 11 ). The structures of capnellene‐8β, 10α‐diol as well as its derivatives were established through standard spectroscopic analysis. The in vitro cytotoxic activities of the eleven compounds were evaluated against Hela, KB, Daoy, and WiDr human tumor cell lines.     

Metabolites with Cytotoxic Activity from the Formosan Soft Coral Cladiella Australis

The metabolites, (24S)‐3β‐acetoxyergost‐5‐en‐21‐oic acid ( 2 ), 5′‐O‐acetylthymidine ( 3 ), 3′‐O‐acetylthymidine ( 4 ), and p‐vinylbenzyl alcohol ( 5 ), along with a known steroid ( 1 ) were isolated from the EtOAc extract of the Formosan soft coral Caldiella australis. The structures of new metabolites were determined on the basis of spectroscopic (including 1D and 2D NMR) analyses and by comparison of their NMR spectral data with those of related compounds. Except for 3 , all compounds exhibited cytotoxic activity of various degrees of potency against a limited panel of human liver and breast cancer cell lines.     

Anthraquinones and Lignans from Cassia occidentalis

One new anthraquinone glycoside, 6‐O‐(α‐L ‐rhamnopyranosyl‐(1→6)‐β‐d‐ glucopyranosyl)emodin ( 1 ), and two new sesquilignans, seslignanoccidentaliols A ( 2 ) and B ( 3 ), were isolated from the whole plant of Cassia occidentalis. The structures of the new compounds were established by means of spectroscopic methods, especially 2D‐NMR data (¹H,¹H‐COSY, HMQC, HMBC, and ROESY), as well as HR‐ESI‐MS analysis. One previously reported sesquilignan, erythro‐guaiacylglycerol‐β‐O‐4′‐(5′)‐methoxylariciresinol, was revised to be seslignanoccidentaliol A ( 2 ). The 6‐O‐(α‐L ‐rhamnopyranosyl‐(1→6)‐β‐d‐ glucopyranosyl)emodin ( 1 ) exhibited moderate anti‐HIV‐1 activity with an EC₅₀ value of 2.90 μg/ml and a therapeutic‐index (TI) value of 260.     

Steroidal Alkaloids from Veratrum dahuricum (Turcz.) Loes. f. with Genotoxicity on Brain Cell DNA in Mice

Two new steroidal alkaloids, 2β‐hydroxyverdine ( 1 ) and tomatillidine 3‐O‐β‐D ‐glucopyranoside ( 2 ), were isolated from the root and rhizome of Veratrum dahuricum (Turcz .) Loes . f., together with four known compounds, i.e., 16‐O‐(2‐methylbutyroyl)germine ( 3 ), veramitaline ( 4 ), jervine ( 5 ), and veratroylzygadenine ( 6 ). Their structures were established by extensive spectroscopic analysis, as well as by comparison with data in literature. Compounds 1 – 6 exhibited genotoxicity on brain cell DNA of the cerebellum and cerebral cortex in mice, evaluated by using single‐cell gel electrophoresis (comet assay).     

Stereocontrolled anionic alternating copolymerization of ethylphenylketene with benzaldehyde by a bisoxazoline ligand

Anionic copolymerization of ethylphenylketene with benzaldehyde with butyllithium or diethylzinc as the initiator proceeded in a perfect 1:1 alternating manner to produce the corresponding polyester, whose repeating unit had two adjacent chiral centers. The relative stereochemistry between these two chiral centers was successfully controlled by the addition of (S,S)‐(‐)‐2,2′‐isopropylidenebis(4‐tert‐butyl‐2‐oxazoline), producing the corresponding polyester that had excellent diastereoselectivity (erythro‐configuration : threo‐configuration = 4:96). The diastereomeric ratio was determined by high‐performance liquid chromatography analysis of the diol, which was obtained by reductive degradation of the polyester while maintaining the configuration of the repeating unit. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5384–5388, 2004     

New Lignans from the Roots of Taiwania cryptomerioides Hayata

The five new lignans designated 3′,4′‐de‐O‐methylenehinokinin ( 1 ), taiwaninolide ( 2 ), 8′‐hydroxysavinin ( 3 ), isoguamarol ( 4 ), and 4′‐O‐methylsalicifolin ( 5 ), as well as the new 4‐(3,4‐dimethoxybenzyl)dihydro‐3‐(4‐hydroxybenzyl)furan‐2(3H)‐one ( 6 ) were isolated from the roots of Taiwania cryptomerioides, besides the three known compounds hinokinin ( 8 ), savinin ( 9 ), and 3,4‐de‐O‐methylenehinokinin ( 7 ). The structures of the new constituents were elucidated through chemical and spectral studies. A compound previously isolated from the heartwood of Chamaecyparis obtusa var. formosana was assigned structure 1 ; however, this structure has now been revised to be 3,4‐de‐O‐methylenehinokinin ( 7 ).     

Chemical Constituents of Ligusticum sinensis Oliv.

The new phenylpropanoid diglycoside ligusinenoside A ( 1 ), and the two new 8,4′‐oxyneolignan(‘8‐O‐4′‐neolignan’) diglycosides ligusinenosides B ( 2 ) and C ( 3 ), together with nine known compounds, were isolated from the rhizomes of Ligusticum sinensis Oliv. The structures of 1 – 3 were elucidated on the basis of spectroscopic analyses.     

Phenolic Compounds from Elsholtzia Bodinieri Van't

Seven phenolic compounds, including one new compound trans‐3,4,3′,5′‐tetrahydroxy‐4′‐methylstilbene 4‐O‐β‐D‐xylopyranosyl‐(1→6)‐β‐D‐glucopyranoside ( 1 ), together with six known compounds (+)‐hinokiol ( 2 ), 6‐hydroxy‐5,7‐dimethoxycoumarin ( 3 ), caffeic acid ( 4 ), vanillic acid ( 5 ), 4‐hydroxy‐2,6‐dimethoxyphenol‐1‐O‐β‐D‐glucopyranoside ( 6 ) and 4‐allyl‐2,6‐dimethoxyphenol‐1‐O‐β‐D‐glucopyranoside ( 7 ), were isolated from the root bark of Elsholtzia bodinieri Van't. Their structures were determined on the basis of spectroscopic and chemical evidence.     

One‐dimensional CuII coordination polymers containing C2h‐symmetric 1,1′:4′,1′′‐terphenyl‐3,3′‐dicarboxylate linkers

Two new one‐dimensional Cu^II coordination polymers (CPs) containing the C_2h‐symmetric terphenyl‐based dicarboxylate linker 1,1′:4′,1′′‐terphenyl‐3,3′‐dicarboxylate (3,3′‐TPDC), namely catena‐poly[[bis(dimethylamine‐κN)copper(II)]‐μ‐1,1′:4′,1′′‐terphenyl‐3,3′‐dicarboxylato‐κ⁴O,O′:O′′:O′′′] monohydrate], {[Cu(C₂₀H₁₂O₄)(C₂H₇N)₂]·H₂O}_n, (I), and catena‐poly[[aquabis(dimethylamine‐κN)copper(II)]‐μ‐1,1′:4′,1′′‐terphenyl‐3,3′‐dicarboxylato‐κ²O³:O^3′] monohydrate], {[Cu(C₂₀H₁₂O₄)(C₂H₇N)₂(H₂O)]·H₂O}_n, (II), were both obtained from two different methods of preparation: one reaction was performed in the presence of 1,4‐diazabicyclo[2.2.2]octane (DABCO) as a potential pillar ligand and the other was carried out in the absence of the DABCO pillar. Both reactions afforded crystals of different colours, i.e. violet plates for (I) and blue needles for (II), both of which were analysed by X‐ray crystallography. The 3,3′‐TPDC bridging ligands coordinate the Cu^II ions in asymmetric chelating modes in (I) and in monodenate binding modes in (II), forming one‐dimensional chains in each case. Both coordination polymers contain two coordinated dimethylamine ligands in mutually trans positions, and there is an additional aqua ligand in (II). The solvent water molecules are involved in hydrogen bonds between the one‐dimensional coordination polymer chains, forming a two‐dimensional network in (I) and a three‐dimensional network in (II).     

Nucleotides. Part LXXIX

Two series of new ribonucleoside 3′‐phosphoramidites (see 36 – 42 ) carrying the photolabile [2‐(2‐nitrophenyl)propoxy]carbonyl group at the 5′‐O‐position were synthesized and characterized as monomeric building blocks for photolithographic syntheses of RNA chips. Base protection was achieved in the well‐known manner by the 2‐(4‐nitrophenyl)ethyl (npe) and the [2‐(4‐nitrophenyl)ethoxy]carbonyl (npeoc) group. The carbohydrate moiety carried in addition the 2′‐O‐(tetrahydro‐4‐methoxy‐2H‐pyran‐4‐yl) group for blocking the 2′‐OH function.     

Steroidal Alkaloids from Veratrum maackii Regel with Genotoxicity on Brain‐Cell DNA in Mice

Two new steroidal alkaloids, 23‐methoxycyclopamine 3‐O‐β‐D ‐glucopyranoside ( 1 ) and isoecliptalbine ( 2 ), were isolated from the root and rhizoma of Veratrum maackii Regel , together with five known compounds, i.e., verussurine ( 3 ), verabenzoamine ( 4 ), verazine ( 5 ), isoverazine ( 6 ), and verazinine ( 7 ). Their structures were established by extensive analysis of spectroscopic data, as well as by comparison with literature data. Compounds 1 – 7 could cause DNA damage in the cerebellum and cerebral cortex of mice in a dose‐dependent manner by using single‐cell gel electrophoresis (comet assay).     

Xanthone O‐Glycosides from the Roots of Pteris Multifida

Two new xanthone glycosides and six known compounds were isolated from the roots of Pteris multifida. Based on spectroscopic and chemical methods, the structures of the new compounds were elucidated as 1‐hydroxy‐4,7‐dimethoxy‐8‐(3‐methyl‐2‐butenyl)‐6‐O‐α‐L‐rhamnopyranosyl‐(1→2)‐[β‐D‐glucopyranosyl‐(1→3)]‐β‐D‐glucopyranosylxanthone ( 1 ), and 1,3‐dihydroxy‐7‐methoxy‐8‐(3‐methyl‐2‐butenyl)‐6‐O‐α‐L‐rhamnopyranosyl‐(1 →2)‐[β‐D‐glucopyranosyl‐(1→3)]‐β‐D‐glucopyranosylxanthone ( 2 ), respectively.     

Oligonucleotides Containing 7‐Deaza‐2′‐deoxyxanthosine: Synthesis,Base Protection,and Base‐Pair Stability

Oligonucleotides incorporating 7‐deaza‐2′‐deoxyxanthosine ( 3 ) and 2′‐deoxyxanthosine ( 1 ) were prepared by solid‐phase synthesis using the phosphoramidites 6 – 9 and 16 which were protected with allyl, diphenylcarbamoyl, or 2‐(4‐nitrophenyl)ethyl groups. Among the various groups, only the 2‐(4‐nitrophenyl)ethyl group was applicable to 7‐deazaxanthine protection being removed with 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) by β‐elimination, while the deprotection of the allyl residue with Pd⁰ catalyst or the diphenylcarbamoyl group with ammonia failed. Contrarily, the allyl group was found to be an excellent protecting group for 2′‐deoxyxanthosine ( 1 ). The base pairing of nucleoside 3 with the four canonical DNA constituents as well as with 3‐bromo‐1‐(2‐deoxy‐β‐D ‐erythro‐pentofuranosyl)‐1H‐pyrazolo[3,4‐d]pyrimidine‐4,6‐diamine ( 4 ) within the 12‐mer duplexes was studied, showing that 7‐deaza‐2′‐deoxyxanthosine ( 3 ) has the same universal base‐pairing properties as 2′‐deoxyxanthosine ( 1 ). Contrary to the latter, it is extremely stable at the N‐glycosylic bond, while compound 1 is easily hydrolyzed under slightly acidic conditions. Due to the pK_a values 5.7 ( 1 ) and 6.7 ( 3 ), both compounds form monoanions under neutral conditions (95% for 1 ; 65% for 3 ). Although both compounds form monoanions at pH 7.0, pH‐dependent T_m measurements showed that the base‐pair stability of 7‐deaza‐2′‐deoxyxanthosine ( 3 ) with dT is pH‐independent. This indicates that the 2‐oxo group is not involved in base‐pair formation.     

Five Aromatics Bearing a 4‐O‐Methylglucose Unit from Cordyceps cicadae

Five new aromatics bearing a 4‐O‐methylglucose unit, namely 3‐methoxy‐1,4‐hydroquinone 1‐(4′‐O‐methyl‐β‐glucopyranoside) (=4‐hydroxy‐3‐methoxyphenyl 4‐O‐methyl‐β‐glucopyranoside; 1 ), 3‐methoxy‐1,4‐hydroquinone 4‐(4′‐O‐methyl‐β‐glucopyranoside) (=4‐hydroxy‐2‐methoxyphenyl 4‐O‐methyl‐β‐glucopyranoside; 2 ), vanillic acid 4‐(4′‐O‐methyl‐β‐glucopyranoside) (=3‐methoxy‐4‐[(O‐methyl‐β‐glucopyranosyl)oxy]benzoic acid; 3 ), 5‐methoxycinnamic acid 3‐O‐(4′‐O‐methyl‐β‐glucopyranoside) (=(2E)‐3‐{3‐methoxy‐5‐[(4‐O‐methyl‐β‐glucopyranosyl)oxy]phenyl}prop‐2‐enoic acid; 4 ), and naphthalene‐1,8‐diol 1,8‐bis(4′‐O‐methyl‐β‐glucopyranoside) (=naphthalene‐1,8‐diyl bis(4‐O‐methyl‐β‐glucopyranoside; 5 ), were isolated from the cultivated Cordyceps cicadae mycelia, together with thirteen known compounds. Their structures were determined by spectroscopic methods. The absolute configurations of the sugar units were not determined.     

7‐Cyclopropyl‐2′‐deoxytubercidin: a carbocyclic side‐chain derivative of 7‐deaza‐2′‐deoxyadenosine

The title compound {systematic name: 4‐amino‐5‐cyclopropyl‐7‐(2‐deoxy‐β‐D‐erythro‐pentofuranosyl)‐7H‐pyrrolo[2,3‐d]pyrimidine}, C₁₄H₁₈N₄O₃, exhibits an anti glycosylic bond conformation, with the torsion angle χ = −108.7 (2)°. The furanose group shows a twisted C1′‐exo sugar pucker (S‐type), with P = 120.0 (2)° and τ_m = 40.4 (1)°. The orientation of the exocyclic C4′—C5′ bond is ‐ap (trans), with the torsion angle γ = −167.1 (2)°. The cyclopropyl substituent points away from the nucleobase (anti orientation). Within the three‐dimensional extended crystal structure, the individual molecules are stacked and arranged into layers, which are highly ordered and stabilized by hydrogen bonding. The O atom of the exocyclic 5′‐hydroxy group of the sugar residue acts as an acceptor, forming a bifurcated hydrogen bond to the amino groups of two different neighbouring molecules. By this means, four neighbouring molecules form a rhomboidal arrangement of two bifurcated hydrogen bonds involving two amino groups and two O5′ atoms of the sugar residues.     

Identification of Three New Flavonoids from the Peels of Citrus unshiu

Three new flavonoids, 5,6,7,8,3′,4′‐hexamethoxyhomoflavone ( 1 ), 5,6,7,8,4′‐pentamethoxyhomoflavone ( 2 ) and 3,6,7,8,2′,5′‐hexamethoxyflavone ( 3 ) were isolated from the peels of mature fruits of Citrus unshiu Marcow (Rutaceae), together with the three known compounds 6,7,8,4′‐tetramethoxyflavone (=6,7,8‐trimethoxy‐2‐(4‐methoxyphenyl)‐4H‐1‐benzopyran‐4‐one), 3,5,7,8,2′,5′‐hexamethoxyflavone (=2‐(2,5‐dimethoxyphenyl)‐3,5,7,8‐tetramethoxy‐4H‐1‐benzopyran‐4‐one), and scopoletin (=7‐hydroxy‐6‐methoxy‐2H‐1‐benzopyran‐2‐one) of which the former two have never been isolated from natural resources, although they have been reported as synthetic compounds. The structures of 1 – 3 were elucidated on the basis of spectroscopic evidence, including 1D‐ and 2D‐NMR analysis.     

Synthesis and Structure of Low‐valent η4‐Cinnamaldehyde Cobalt Complexes

Three η⁴‐(C=C–C=O) coordination cobalt(I) complexes 1 – 3 were synthesized by the reactions of cinnamaldehyde, p‐fluorocinnamaldehyde, and p‐chlorocinnamaldehyde with CoMe(PMe₃)₄. Complex 4 as η²‐(C=C) coordination was prepared by the reaction of chalcone with Co(PMe₃)₄. The structures of complexes 1 – 4 were confirmed by single‐crystal X‐ray diffraction. Although the reactions didn't undergo C–H bond activation and decarbonylation, the formation of complexes 1 – 4 deepens our understanding of the reactions between α,β‐unsaturated aldehyde or ketone with low‐valent central cobalt atom.     

A threefold interpenetrating two‐dimensional zinc(II) coordination polymer: synthesis,crystal structure and selective luminescence sensing properties

The Fe³⁺ ion is the most important element in environmental systems and plays a fundamental role in biological processes. Iron deficiency can result in diseases and highly selective and sensitive detection of trace Fe³⁺ has become a hot topic. A novel two‐dimensional Zn^II coordination framework, poly[[μ‐4,4′‐bis(2‐methylimidazol‐1‐yl)diphenyl ether‐κ²N³:N^3′](μ‐4,4′‐sulfonyldibenzoato‐κ²O:O′)zinc(II)], [Zn(C₁₄H₈O₆S)(C₂₀H₁₈N₄O)]_n or [Zn(SDBA)(BMIOPE)]_n, (I), where H₂SDBA is 4,4′‐sulfonyldibenzoic acid and BMIOPE is 4,4′‐bis(2‐methylimidazol‐1‐yl)diphenyl ether, has been prepared and characterized by IR, elemental analysis, thermal analysis and X‐ray diffraction analysis, the latter showing that the coordination polymer exhibits a threefold interpenetrating two‐dimensional 4⁴‐ sql network. In addition, it displays a highly selective and sensitive sensing for Fe³⁺ ions in aqueous solution.     

Semisynthesis and absolute configuration of a novel rearranged 19,20‐δ‐lactone (9βH)‐pimarane diterpene

Annonalide (3β,20‐epoxy‐3α,16‐dihydroxy‐15‐oxo‐7‐pimaren‐19,6β‐olide, C₂₀H₂₆O₆, 1 ) is the major (9βH)‐pimarane diterpene isolated from tubers of Cassimirella ampla, and it exhibits cytotoxic properties upon interaction with ctDNA. We have prepared new derivatives of 1 by modification of the (9βH)‐pimarane backbone and report here the semisynthesis and absolute configuration of a novel rearranged 19,20‐δ‐lactone (9βH)‐pimarane. Our approach was the reduction of the carbonyl groups of 1 with sodium borohydride, at positions C15 (no stereoselectivity) and C3 (stereoselective reduction), followed by rearrangement of the 6,19‐γ‐lactone ring into the six‐membered 19,20‐δ‐lactone ring in 4a (3β,6β,16‐trihydroxy‐7‐pimaren‐19,20β‐olide monohydrate, C₂₀H₃₀O₆·H₂O). The absolute structure of the new compound, 4a , was determined unambiguously with a Flack parameter x of −0.01 (11), supporting the stereochemistry assignment of 1 redetermined here. Besides the changes in the pattern of covalent bonds caused by reduction and lactone rearrangement, the conformation of one of the three fused cyclohexane rings is profoundly different in 4a , adopting a chair conformation instead of the boat shape found in 1 . Furthermore, the intramolecular hydrogen bond present in 1 is lost in new compound 4a , due to hydrogen bonding between the 3‐OH group and the solvent water molecule.