A New Biflavonoid from Stellera chamaejasme L.

A new biflavonoid, stelleranol, was isolated from the roots of Stellera chamaejasme L..Its structure was determined by the analysis of MS and NMR data, especially 2D NMR spectra.     

Monepaloside K,a New Triterpenoid Saponin from Morina nepalensis var.alba Hand.—Mazz.

One new triterpenoid saponin,monepaloside K(1) was isolated from the water-soluble part of the whole plant of a famous Tibetan medicinal herb,morina neplaensis var. alba Hand.-Mazz.Its structure was determined to be 3-O-α-L-arabinopyranosyl-(1→3)-β-D-xylopyranosyl siaresinolic acid on the basis of spectroscopic evidences,especially 2D NMR techniques.     

A Nove Asymmetric ent—Kauranoid Dimer from Isodon enanderianus

Further investigation on the aerial parts of Isodon enanderianus afforded a novel asymmetric ent-kauranoid dimer,enanderi-nanin J(1).The structure of the dimer was elucidated by means of spectroscopic methods (including 2D NMR tecniques ),Enanderinanin J was a dimer of xerophilusin A and probably formed by [4 2] cycloaddition.     

A new eudesmane sesquiterpene glycoside from Parepigynum funingense

A new eudesmane sesquiterpene glycoside,1α,6β-dihydroxy-5,10-bis-epi-eudesm-4(15)-ene-6-O-β-D-glucopyranoside(2), together with a known analogue compound,1α,6β-dihydroxy-5,10-bis-epi-eudesm-3-ene-6-O-β-D-glucopyranoside(1),were isolated from the roots of Parepigynumfuningense.The structure of 2 was determined by 1D and 2D NMR spectroscopy.Compound 1 was isolated from this plant for the first time.     

A New Isomalabaricane Triterpenoid from Sponge Jaspis sp.

From the marine sponge Jaspis sp., a new isomalabaricane triterpenoid 22, 23-dihydrostellettin D (1) was isolated, and its structure was established on the basis of IR, MS and extensive 2D NMR spectroscopic analysis. It is a unique skeleton compound rarely obtained from Chinese marine organisms.     

Study on the Total Synthesis of Et 743 and its Analogues： Synthesis of a Tricyclic Intermediate and its 11-Epimer

The tricyclic compound 1, a key intermediate of the pentacyclic core of Et 743 and its analogues, was synthesized. Its 11-epimer was found as the product of racemization when BOP was used as the coupling agen4 but not when BOP-Cl used in the same reaction. The stereochemistry of both isomers was confirmed on basis of the ^1H NMR and NOE-difference spectra.     

A new cycloartane nortriterpenoid from Quercus variabilis Blume

The leaves and stems of Quercus variabilis Blume afforded a new cycloartane nortriterpenoid,3α-acetyloxy-4α,14α-dimethyl-9β, 19-cycloergost-24-oic acid(1),along with five known compounds(2-6).The structure of 1 was elucidated by 1D and 2D NMR and mass spectroscopy.     

A Novel Fortunate A from Cryptomerica fortunei

A novel compound, named fortunate A, was isolated from the ethanol extract of the stem bark of Cryptomerica fortunei. Its structure was established on the basis of the spectral evidences including 1D and 2D NMR spectrum.     

Structureal Study of Inclusion COmplex of Adrographolide with β-Cyclodextrin Prepared under Microwave Irradiation

An inclusion complex of β-cyclodextrin with andrographolide (Andro) was prepared by using a convenient method of microwave irradiation.The structure of the inclusion complex was determined by the ^1H NMR,2D NMR spectroscopy as well as the elemental analysis.     

Synthesis and Properties of Gemini Cationic Surfactants with Amide Spacers

Four gemini cationic surfactants {N,N‘-di[2-(lauryldimethylamino)acetyl]polymethylenediamine dichloride, LAA-s-LAA, s = 2,3,4,6 } were synthesized by using four bis (a-chloroacetamide)s and N, N-dimethyl-laurylamine, respectively. The molecular structures were characterized by means of IR, ^1H NMR. ^13C NMR and MS, and the behavior of their aqueous solutions was studied. The critical micell concentrations (CMC) of LAA-s-LAA were one order of magnitude lower than that of dodecyltrimethyl ammonium chloride (DTAC). With the change of the length of spacer chain(s), their CMC values change, and CMC reaches the top value at s=4.     

A New Flavonol Oligosaccharide from the Seeds of Aesculus chinensis

Aesculus chinensis is a traditional chinese medicinal plant widely distributed in China, which has been used to treat stomach disease. From recent research its seeds contain many flavonoids and proanthocyanidin A2, which have potential venotonic and vasoprotective action and powerful antioxidant activity. In this paper, we report the isolation and the structure elucidation of a new flavonol oligosacchride. Bioassay results showed that the compound exhibited an antivirus activity. …     

Ultrafast Single-Scan 2D NMR Spectroscopic Detection of a PHIP-Hyperpolarized Protease Inhibitor

Two-dimensional NMR spectroscopy is one of the most important spectroscopic tools for the investigation of biological macromolecules. However, due to the low sensitivity of NMR spectroscopy, it takes usually from several minutes to many hours to record such spectra. Here, the possibility of detecting a bioactive derivative of the sunflower trypsin inhibitor-1 (SFTI-1), a tetradecapeptide, by combining parahydrogen-induced polarization (PHIP) and ultrafast 2D NMR spectroscopy is shown. The PHIP activity of the inhibitor was achieved by labeling with O-propargyl-l -tyrosine. In 1D PHIP experiments a signal enhancement of a factor of approximately 1200 compared to standard NMR was found. This enhancement permits measurement of 2D NMR correlation spectra of low-concentrated SFTI-1 in less than 10 seconds, employing ultrafast single-scan 2D NMR detection. As experimental examples PHIP-assisted ultrafast single-scan TOCSY spectra of SFTI-1 are shown.     

Monofunctionalized pillar[5]arene-based stable [1]pseudorotaxane

A new monofunctionalized pillar[5]arene bearing imidazolium moiety that formed stable [1]pseudorotaxane even at high concentration (100 mmol/L) was reported. [1]Rotaxane was obtained effi ciently through thiol-ene reaction from [1]pseudorotaxane which further confi rmed the formation of [1]pseudorotaxane.     

石杉碱O的结构鉴定

蛇足石杉[Huperziaserrata(Thunb.)Trev.]中,R~f与石杉碱甲相近部位分离得到一个新生物碱,经IR,MS,1D和2DNMR确定了其化学结构,为一个有内氢键烯醇型新的lycopodine类生物碱,命名为石杉碱O(HuperzineO)。     

Preparation and study on the solid inclusion complex of cloxacillin sodium with beta-cyclodextrin

The interaction of cloxacillin sodium with beta-cyclodextrin (beta-CD) has been studied by several analytical techniques, including (1)H NMR, fluorescence spectroscopy, infrared spectroscopy. In this paper, solid inclusion complex of cloxacillin sodium with beta-CD was synthesized by the coprecipitation method. In addition, the characterization of the inclusion complex has been proved by fluorimetry, infrared spectroscopy and 1D, 2D NMR. The experimental results confirmed the existence of 1:1 inclusion complex of cloxacillin sodium with beta-CD. The formation constant of complex was determined by fluorescence method and (1)H NMR. Spacial configuration of complex has been proposed on 2D NMR technique.     

利用选择性激发核磁共振对混合物中的两种化合物进行结构解析

利用现代NMR的1D、2D技术对一个混合物进行了分析。结果表明：混合物由两种化合物组成。为了同时准确确定两种化合物的结构，本工作应用了1D-TOCSY技术，利用该技术选择性强的特点来补充常规的1D、2DHMR实验所提供的分子结构的信息。在没有进行预分离的条件下，顺利地完成了样品中两种化合物的核磁信号归属，并最终确定了它们的结构。     

Trachylobagibberellin类似物的化学合成研究（Ⅰ）──12．16R－环赤霉低酸甲酯的合成

Ｔｒａｃｈｙｌｏｂａｇｉｂｂｅｒｅｌｌｉｎ类似物的化学合成研究（Ⅰ）──１２．１６Ｒ－环赤霉低酸甲酯的合成谢文革，崔育新，马建泰，潘鑫复（兰州大学化学系，兰州大学应用有机化学国家重点实验室，兰州，７３００００）关键词Ｔｒａｃｈｙｌｏｂａｇｉｂｂｅｒｅ...     

1H and 13C NMR assignments for four triterpenoid saponins from Albizziae cortex

Four triterpenoid saponins were isolated from Albizziae cortex, and a complete assignment of their (1)H and (13)C NMR spectra was carried out using 1D and 2D NMR ((1)H-(1)H COSY, HSQC, HMBC, and HSQC-TOCSY) methods. Their (1)H NMR assignments were reported for the first time and some of their (13)C NMR spectral data reported in literature were corrected.     

Bishyoscyamine, one unusual dimeric tropane alkaloid from Anisodus acutangulus

One unusual dimeric tropane alkaloid, bishyoscyamine, was isolated from the roots of Anisodus acutangulus, whose structure including the absolute stereochemistry was unambiguously determined based on extensive 1D NMR and 2D NMR, HR-ESI-MS [α]D and CD spectroscopic analyses. To our knowledge, bishyoscyamine is the first example of tropane alkaloid dimer condensed by a C-N bond.     

Automated structure verification based on a combination of 1D (1)H NMR and 2D (1)H - (13)C HSQC spectra

A method for structure validation based on the simultaneous analysis of a 1D (1)H NMR and 2D (1)H - (13)C single-bond correlation spectrum such as HSQC or HMQC is presented here. When compared with the validation of a structure by a 1D (1)H NMR spectrum alone, the advantage of including a 2D HSQC spectrum in structure validation is that it adds not only the information of (13)C shifts, but also which proton shifts they are directly coupled to, and an indication of which methylene protons are diastereotopic. The lack of corresponding peaks in the 2D spectrum that appear in the 1D (1)H spectrum, also gives a clear picture of which protons are attached to heteroatoms. For all these benefits, combined NMR verification was expected and found by all metrics to be superior to validation by 1D (1)H NMR alone. Using multiple real-life data sets of chemical structures and the corresponding 1D and 2D data, it was possible to unambiguously identify at least 90% of the correct structures. As part of this test, challenging incorrect structures, mostly regioisomers, were also matched with each spectrum set. For these incorrect structures, the false positive rate was observed as low as 6%.