13C-NMR-Untersuchungen zur Strukturaufklärung von Polysacchariden und deren Methylderivaten

The ¹³C NMR spectra of some polysaccharides and their methyl derivatives have been analysed. The numbers and positions of the assigned ¹³C NMR signals give some information about the structure of the monomer unit and the positions of the glycosidic linkage but no information about the anomeric configuration. In this case the ¹J(C-1, H) coupling constants make it possible to identify the anomeric configuration, because the mean differences of the J values for the α- and β-anomers are 12 Hz (at least 5 Hz) with the higher values for the α-anomers.     

1H NMR Study of Methyl O-Acetyl-α-and-β-D-Xylopyranosides Conformational Studies and Non Additivity of 1H-Shift Increments

Abstract

¹H NMR spectra of the complete series of fully and partially acetylated methyl α-and β-D-xylopyranosides have been studied. The α-anomers occur exclusively in ⁴C₁ chairs but the ¹C₄ chair becomes increasingly populated in the β-forms especially when the OH-3 is not acetylated. Increments used for the prediction of the chemical shifts of ring protons are discussed and compared with the literature data. The predictability for changes in shifts upon acetylation is poor.     

玉米须中的一个新黄酮和两个尿素苷

玉米须是我国传统中药, 具有多种生物活性. 为了寻找玉米须中的生物活性成分, 对玉米须的化学成分进行了研究, 从中分离得到一个新黄酮1和两个尿素苷2和3. 应用多种波谱学方法(¹H NMR, ¹³C NMR, HSQC, HMBC, ¹H-¹H COSY, ESI-MS等), 确定了3个化合物的化学结构. 化合物1为新化合物, 鉴定为6-乙酰基-木犀草素; 化合物2和3是两个新的天然产物, 分别鉴定为鼠李糖尿素苷和1,3-二鼠李糖尿素苷. 首次对两个新天然产物的氢谱和碳谱数据进行了全归属.     

A mycophenolic acid derivative from the fungus Penicillium sp. SCSIO sof101

Abstract

Mycophenolic acid (MPA) is a group of metabolite derived from several species of Penicillium, which shows potent bioactivity. In this study, a new derivative of MPA compound named penicacid D (1), was isolated from the marine derived fungus Penicillium sp. SCSIO sof101, along with seven known compounds (2-8). Their structures were elucidated based on the HR-ESI-MS and NMR data. Moreover, the ¹H and ¹³C NMR data of compound 2 and the ¹³C NMR data of compound 3 are reported. Compounds 1, 4 and 6 exhibited weak activities against Escherichia coli (clinical isolation number 100385570) and Acinetobacter baumannii (clinical isolation number 100069).     

A new lactam alkaloid from Portulaca oleracea L. and its cytotoxity

A new lactam alkaloid named oleraciamide D (1), indentified as (5R)-4-(3-methoxy-4-hydroxyphenyl)-5-(4-hydroxyphenyl)-5,6-dihydropyridin-2(1H)-one, together with five known compounds, indole-3-aldehyde (2), portulacatone (3), N-trans-feruloyloctopamine (4), N-trans-feruloyl-3′-O-methyldopamine (5) and N-trans-feruloyltyramine (6) were isolated from Potulaca oleracea L. Among them, indole-3-aldehyde (2) was isolated from the medicine for the first time. The structure of the new alkaloid was elucidated via UHPLC-ESI-Q-TOF/MS, 1D NMR and 2D NMR. The five known compounds were established by comparing the ¹H-NMR and ¹³C NMR with the reported literature. Oleraciamide D (1) showed cytotoxicity against SH-SY5Y cells when concentration at 50 uM by CCK-8 method.     

Synthesis and PMR specta of α- and β-D-arabinofuranosyluracils

The α- and β-anomers of N¹- and N³-monoglycosylated and N¹,N³-diglycosylated nucleosides have been synthesized by the condensation of 1-OMe- or 1-O-acetyl-2,3,5-tri-O-benzoyl-D-arabinose with bis(trimethylsilyl)uracil in the presence of SnCl₄. The structures of the compounds obtained were established from their NMR spectra.     

Structure of aldose condensation products with 2-hydroxyand 2-sulfanylbenzohydrazides

The structure of the condensation products of 2-hydroxy- and 2-sulfanylbenzohydrazides with a series of aldoses (L-arabinose, D-ribose, L-ramnose, D-galactose, D-glucose, D-mannose) was studied by ¹H and ¹³C NMR spectroscopy. The condensation products of monosaccharides with 2-hydroxybenzohydrazide in DMSO-d ₆ solution exist as equilibrium mixtures of linear hydrazone and cyclic pyranose and furanose forms, the cyclic tautomers being represented by two stereoisomers (α- and β-anomers). The aldose condensation products with 2-sulfanylbenzohydrazide in the crystalline state have cyclic 1,3,4-benzothiadiazepine structure, while in DMSO-d ₆ solution they undergo complete or partial isomerization into cyclic pyranose tautomer.     

Chemical constituents from Curcuma longa L. and their inhibitory effects of nitric oxide production

A new bisabolane-type sesquiterpenoid, turmerone Q (1), along with six known compounds (2–7), were isolated from the rhizomes of Curcuma longa L. The structural elucidation of the new compound was conducted using ¹H NMR, ¹³C NMR, HSQC, HMBC and NOESY spectroscopic analyses. The absolute configuration of 1 was elucidated by comparison of the experimental and calculated ECD spectra. The anti-inflammatory effects of 1–7 were evaluated through lipopolysaccharide-induced nitric oxide (NO) production in RAW 264.7 macrophages assays, and compounds 6 and 7 showed potent inhibitory activity against NO production.     

Synthesis of Mono- and Disaccharide 4-[(ω-Sulfanylalkyl)oxy]benzoylhydrazones as Potential Glycoligands for Noble Metal Nanoparticles

A procedure has been developed for the synthesis of previously unknown aldose 4-[(ω-sulfanylalkyl) oxy]benzoylhydrazones (where alkyl is hexyl or decyl and aldoses are D-glucose, D-galactose, D-maltose, and D-lactose) that a repromising glycoligands for noble metal nanoparticles. According to the ¹H and ¹³C NMR data, 4-[(ω-sulfanylalkyl)oxy]benzoylhydrazones derived from D-glucose, D-maltose, and D-lactose in crystal and in DMSO-d₆ solution have exclusively the cyclic pyranose structure (α- and β-anomers). D-Galactose 4-[(ω-sulfanylalkyl)oxy]benzoylhydrazones in DMSO-d₆ solution exist as tautomeric mixtures of cyclic pyranose and open-chain acylhydrazone structures.

     

A new anthraquinone and eight constituents from Hedyotis caudatifolia Merr. et Metcalf: isolation,purification and structural identification

Hedyotis caudatifolia Merr. et Metcalf. (HC), a folk medicine in Yao nationalities areas in China, was used to investigate the chemical constituents. Through silica gel and Sephadex LH-20 column chromatography, nine compounds were isolated and purified. By physical and chemical properties, IR, MS (EI-MS, high resolution EI-MS), 1D NMR (¹H NMR, ¹³C NMR) and 2D NMR (HSQC, ¹H–¹H COSY, HMBC), their structures were identified as β-sitosterol (1), stigmasterol (2), scopolin (3), 2-hydroxy-1,7,8-trimethoxyanthracene-9,10-dione (4), oleanolic acid (5), ursolic acid (6), methyl barbinervate (7), β-daucosterol (8) and p-Hydroxybenzoic acid (9). These compounds were isolated from HC for the first time, and 4 a new anthraquinone whose biological activities are worth to be investigated in future. These compounds may contribute to the HC’s pharmacological effects on treating diseases, and may be used as candidates for control index in establishing the quality control standard of HC.     

Convenient Synthesis and Purification of N-Trifluoroacetylated Neuraminic Acid Tetraol: A Key Precursor for the Synthesis of New Sialyl Donors Containing Labile O-Acyl Protecting Groups

A convenient synthesis and separation of α- and β-anomers of methyl (phenyl 3,5-dideoxy-2-thio-5-trifluoroacetamido-D-glycero-D-galacto-nonulopyranosid)onate (6a and 6b) on a multigram scale was developed. Both α- and β-isomers of 6 were obtained as crystals suitable for safe storage. The β-isomer forms a crystalline solvate with methanol. Fully O-trichloroacetylated and O-trifluoroacetylated N-trifluoroacetyl thiosialosides were synthesized in an efficient manner from the β-tetraol 6b.     

Synthesis of a New Cavitand. 2 C60 Complex

Abstract

A new cavitand 2 and its complexation with fullerene to afford complex 3 was prepared and characterized by spectroscopic methods. Macrocycle 2 was studied in solution by NMR, and in the solid state by ¹³C CP-MAS, NMR and X-ray diffraction. The macrocycle 2 can host 2 fullerene C₆₀ molecules in its structure. For the complex 3, π-π, CH-π and n-π interactions were observed by ¹³C CP-MAS and FTIR spectroscopy. MM and MD calculations were carried out.     

Antifungal activity against Botrytis cinerea of labdane-type diterpenoids isolated from the resinous exudate of Haplopappus velutinus Remy (Asteraceae)

Two labdane diterpenoids were isolated, from the resinous exudate of Haplopappus velutinus Remy (Asteraceae); the main compound was identified as 7,13-(E)-labdadien-15,18-dioic-acid-18-methyl ester (1) and the minor compound identified as 7-labden-15,18-dioic-acid-18-methyl ester (2). Their structures were obtained using FTIR, MS, HRMS and NMR data: 1D NMR (¹H, ¹³C and DEPT-135), 2D homonuclear NMR (COSY and NOESY) and heteronuclear NMR (HSQC and HMBC). The trans stereochemistry of the decalin moiety of compounds 1 and 2 was established through NOESY experiments of the reduction product of 1; 7-labden-15,18-diol (1a). Diterpenoids 1 and 1a are described for the first time and showed antifungal activity, inhibiting approximately 40% mycelial growth of Botrytis cinerea.     

A new benzofuran from Artemisia halodendron Turcz. ex Bess.

A new benzofuran, methyl (2S,2″S,3′E)-[2-(1″-acetoxypropan-2-yl)-2,3-dihydrobenzofuran-5-yl]acrylate (1), and 13 known compounds (2–14) were isolated from an ethanol extract of Artemisia halodendron Turcz. ex Bess. The chemical structures of these compounds were determined by 1D and 2D NMR (¹H-¹H COSY, HMBC, HMQC and NOESY) and HR-ESI-MS spectra, and results were compared with data from the literature. The effects of compounds 1–14 were measured on NF-κB activation, with compounds 2 and 3 exhibiting inhibitory activities against TNF-α-induced NF-κB reporter gene expression in HeLa cells from 10 to 100 μM.     

柔荑软珊瑚Nephthea sp.中两种具有细胞毒活性的甾醇化合物

采用抗肿瘤活性追踪法对采自中国南海西沙群岛永兴岛柔荑软珊瑚Nephthea sp.中抗肿瘤活性成分进行研究, 报道了两种具有细胞毒活性的甾醇化合物, 经过MS, IR, ¹H NMR, ¹³C NMR (DEPT), HSQC 和HMBC等光谱技术鉴定为: 24-甲基胆甾-5-烯-3β,8β-二醇(1)和24-亚甲基胆甾-4-烯-3β,6β-二醇(2), 化合物1为新化合物, 利用X-ray单晶衍射技术验证化合物2的立体结构. 化合物1对肝癌细胞(BEL-7402), 小鼠白血瘤细胞(P₃₈₈)和人结肠癌细胞(LOVO)作用的IC₅₀值分别为18.0, 25.5和20.6 μg/mL; 化合物2对肿瘤细胞P₃₈₈和人乳腺癌细胞(MCF)作用的IC₅₀值分别为1.0和2.5 μg/mL.     

Synthesis and Characterization of Chloropentaaryloxycyclotriphosphazene Derivatives

Five chloropentaaryloxycyclotriphosphazene derivatives were synthesized by the reaction of hexachlorocyclotriphosphazene with potassium phenoxide in tetrahydrofuran. A satisfactory yield could be obtained when a 5.1 : 1(KOC ₆ H ₄ R : P ₃ N ₃ Cl ₆ ) molar ratio was used. The new compounds were characterized by IR, ¹H NMR, ³¹P NMR, ¹³C NMR, and ESI-MS, and for two of them by HR-MS.     

A new minor diketopiperazine from the sponge-derived fungus Simplicillium sp. YZ-11

Chemical investigation of the cultures of a sponge-derived fungus Simplicillium sp. YZ-11 led to the isolation of a new minor diketopiperazine alkaloid cyclo-(2-hydroxy-Pro-Gly) (1) and a natural lactone (S)-dihydro-5-[(S)- hydroxyphenylmethyl]-2(3H)-furanone (2), together with five known ergostane-type sterols (3–7). Their structures were established based on extensive spectroscopic methods (¹H and ¹³C NMR, ¹H-¹H COSY, HSQC and HMBC) and optical rotation analysis.     

Two new hirsutane-type sesquiterpenoids chondrosterins N and O from the marine fungus Chondrostereum sp.

The marine fungus Chondrostereum sp. was collected from a soft coral Sarcophyton tortuosum from the South China Sea. This fungus was cultured in glucose-peptone-yeast (GPY) medium and the culture broth was extracted with EtOAc. By the method of ¹H NMR pre-screening and tracing the diagnostic proton signals of the methyl groups, two new hirsutane-type sesquiterpenoids, chondrosterins N and O (1 and 2) were isolated from the metabolite extracts. Their structures were elucidated on the basis of MS, 1D and 2D NMR data.     

Stereoselektive Synthese von 2′-O-(2-Methoxyethyl)ribonucleosiden: Nachbargruppenbeteiligung der Methoxyethoxy-Gruppe bei der Ribosylierung von Heterocyclen

Stereoselective Synthesis of 2′-O-(2-Methoxythyl)ribonucleosides: Neighboring-Group Participation of the Methoxythoxy Group in the Ribosylation Step A new access to 2′-O-(2-methoxyethyl)ribonucleosides, building blocks for second-generation antisense oligonucleotides, is presented. The influence of various reaction parameters on the coupling reaction of 2-O-(2-methoxyethyl)-D -ribose derivatives with heteroaromatic bases as the key step was investigated, and reaction conditions were optimized with regard to formation of the desired β-D -anomers. With Sn²⁺ salts as promotors in polar solvents, these β-D -anomers were formed with a high degree of steroselectivity.     

Owariensisone: a new iridolactone from the whole plant of Brillantaisia owariensis P. Beauv

From the whole plant of Brillantaisia owariensis P. Beauv, a new iridolactone, owariensisone (1) together with six known compounds (nepetin-7-O-glucoside, choline, sucrose, mannitol, xylitol, 1-O-palmitoyl-2-eicosanoyl-3-O-(6-amino-6-deoxy)-β-d-glucopyranosyl-glycerol) were isolated. Structures of these compounds were established by direct interpretation of their spectral data, mainly HR-TOFESIMS, 1-D NMR (¹H and ¹³C) and 2-D NMR (¹H-¹H COSY, HSQC, HMBC, NOESY, TOCSY and DOCSY) and by comparison with the literature.