DEPT Experiments Research Articles

New Withanolides and Other Constituents from the Fruit of Withania somnifera

AbstractFor Abstract see ChemInform Abstract in Full Text.

New taxane diterpenoids from the leaves and twigs of Taxus sumatrana.

Two new taxoids, taxumairol Q (1) and 13-O-acetyl wallifoliol (2), have been isolated from the leaves and twigs of Taxus sumatrana. Taxuspine F and wallifoliol (10) have been isolated for the first time from the yew T. sumatrana. Seventeen known taxoid diterpenoids have also been isolated. The new derivatives, 9,13-diacetyltaxumairol W (3), 10,13-dibenzoyltaxacustin (4), 7,13-diacetylwallifoliol (5), 7,13-dibenzoylwallifoliol (6), and 7,9-dibenzoyltaxumairol P (7), have been prepared by acylation of a crude mixture of taxoids. All structures were established primarily on the basis of 1D and 2D NMR techniques, including DEPT, COSY, and HMBC experiments, as well as chemical correlation with known compounds. Wallifoliol (10) exhibited significant cytotoxicities against both Hepa 59 T/VGH (human liver carcinoma) and KB (human oral epidermoid carcinoma) tumor cells. Taxuspine F and compound 5 possessed moderate activity against Hepa cells only, while 3, 6, 7, and 10-deacetylbaccatin III showed only marginal activity against Hepa cells.

New withanolides and other constituents from the fruit of Withania somnifera.

Two new steroidal lactones of the withanolide-type, 5beta, 6alpha, 14alpha, 17beta, 20beta-pentahydroxy-1-oxo-20 S, 22R-witha-2, 24-dienolide (1)and 6alpha, 7alpha-epoxy-5alpha, 14alpha, 17alpha, 23beta-tetrahydroxy-1-oxo-22R-witha-2, 24-dienolide (2), were isolated from the fruit of Withania somnifera (L.) Dunal (Solanaceae) growing in Southern Egypt, together with two known coumarins, scopoletin (3)and aesculetin (4), a known triterpene, viz. Beta-amyrin (5), and two known phytosterols, viz. stigmasterol (6) and sitosterol (7). The structures of the isolated compounds have been elucidated by spectroscopic methods including UV, IR, (1)H-, (13)C-NMR, DEPT experiments, HRFAB-, FAB-, and EI-mass spectrometry. The in vitro antimicrobial activity of the new withanolide (1) and the alcoholic fruit extract are discussed.

Complete assignment of 1H and 13C NMR spectra of new pentacyclic triterpene acid benzyl esters

AbstractComplete assignments of 1H and 13C NMR chemical shifts for newly synthesized benzyl esters of oleanolic, ursolic and crataegolic acid based on DEPT, HSQC, HMBC, COSY, TOCSY, NOE and ROESY experiments are reported. Copyright © 2002 John Wiley & Sons, Ltd.

Iristectorone K, a novel monocyclic triterpene ester from Iris germanica rhizomes growing in Turkey

A new monocyclic triterpene ester (1) was isolated from the rhizomes of Iris germanica from Turkey. Structure elucidation of compound (1) was carried out by the combined application of HMQC, HMBC, DEPT, COSY and NOESY experiments and named as iristectorone K.

Kaempferol triosides from Silphium perfoliatum

Two apiose-containing kaempferol triosides, together with nine known flavonoids were isolated from the leaves of Silphium perfoliatum L. Their structures were elucidated by acid hydrolysis and spectroscopic methods including UV, LSI MS, FAB MS, CI MS, 1H, 13C and 2D-NMR, DEPT, HMQC and HMBC experiments. The two new compounds were identified as kaempferol 3- O-β- d-apiofuranoside 7- O-α- l-rhamnosyl-(1‴′→6‴)- O-β- d-galactopyranoside and kaempferol 3- O-β- d-apiofuranoside 7- O-α- l-rhamnosyl-(1 ⁗→ 6‴)- O-β- d (2‴- O- E-caffeoylgalactopyranoside).

Isolation and identification of antioxidants from Sophora japonica

A new flavonol triglycoside, kaempferol 3- O - f - l -rhamnopyranosyl-(1 M 6)- g - d -glucopyranosyl-(1 M 2)- g - d -glucopyranoside ( 1 ), as well as two known kaempferol 3- O -[ f - l -rhamnopyranosyl-(1 M 6)]-[ g - d -glucopyranosyl-(1 M 2)]- g - d -glucopyranoside ( 2 ) and kaempferol 3- O - g - d -glucopyranosyl-(1 M 2)- g - d -glucopyranoside-7- O - f - l -rhamnopyranoside ( 3 ), were isolated from the n -BuOH extract of the pericarps of Sophora japonica by bioassay-guided fractionation. The structure of compound 1 was established by UV, IR, MS, and one- and two-dimensional NMR spectroscopy, including DEPT, NOESY, DQF-COSY, TOCSY, HMQC, and HMBC experiments. Compounds 1 - 3 showed antioxidative activity in DPPH and cytochrome-c assay using HL-60 cell system.

Controlled alternating copolymerization of St with MAh in the presence of DBTTC

The copolymerization of styrene (St) with maleic anhydride (MAh) performed at 22 °C in the presence of dibenzyl trithiocarbonate exhibits controlled nature evidenced by: narrow molecular weight distribution, controlled molecular weight and first-order polymerization kinetics. The composition analysis of the copolymers obtained by 13C NMR spectra shows the molar fraction of St in obtained copolymers is almost equal to 0.5 throughout the copolymerization. The sequence structure of the copolymer was obtained from DEPT experiments by recording the spectra at π/4 and 3π/4, and then combining them together, the results showed that the copolymers obtained possessed well-defined alternating structure. The experiment shows that charge-transfer-complex formed from St and MAh participates in both initiation and chain growth throughout the copolymerization.

NMR analysis of a series of photochromic pyranocarbazoles

AbstractThe study of the 1H and 13C resonance spectra of a series of 13 photochromic pyranocarbazoles was carried out using two‐dimensional methods. 1H and 13C resonances were deduced from the concerted application of HSQC, HMBC and DEPT experiments. Copyright © 2001 John Wiley & Sons, Ltd.

Quantitative (13)C NMR analysis of lignins with internal standards.

Novel protocols for acquiring quantitative (13)C NMR spectra of lignins have been developed using the internal reference compounds 1,3,5-trioxane and pentafluorobenzene. Trioxane offers a convenient internal standard for collecting inverse gated proton decoupled (13)C NMR spectra for lignins, whereas pentafluorobenzene can be used to provide information on the amount of methine carbon using the DEPT experiment. In each case, the internal reference compounds provide single, un-overlapped sharp signals in the middle of the spectral region, permitting facile integration. These integrals could be used to determine the amounts of different structural features of lignins, expressed in absolute units of millimoles per gram. The optimum parameters for these experiments were validated for a variety of spectrometer platforms, and standard errors were determined for different spectral areas using lignin model compounds and "standard" lignins. In addition, the data derived for the International Round Robin "standard" lignins showed good agreement with the data from quantitative (31)P NMR spectroscopy and published data, obtained by independent laboratories using independent methods of analysis.

Kaempferol triosides from Reseda muricata

A flavonoid trioside and its coumaryl ester together with seven known flavonoids and five phenolic acids were isolated from the leaves of Reseda muricata. Their structures were elucidated by spectroscopic methods including UV, FAB MS, 1H, 13C and 2D-NMR, DEPT, HMBC and HMQC experiments. The two compounds were identified as kaempferol 3- O-β- d-glucopyranosyl-(1‴ → 2″)- O-α- l-rhamnopyranoside 7- O-β- d-glucopyranoside and kaempferol 3- O-β- d-glucopyranosyl-(1‴ → 2″)- O-α- l rhamnopyranoside 7- O-β- d-(6 ⁗- O- E-coumarylglucopyranoside), respectively.

Reactions of 6‐aminopyrimidines with 2‐dimethylaminomethylenetetralone. Regiospecific Synthesis Of 5,6‐Dihydrobenzo [h]pyrimido [4,5‐b] quinolines

AbstractBenzo[h]pyrimido[4,5‐b]quinolines (3) have been synthesized via a regiospecific cyclocondensation reaction between 6‐aminopyrimidines (1) and 2‐dimethylaminomethylentetralone hydrochloride (2). The linear structure of the final compounds were determined by nmr measurements, especially by 1H,1H, 1H,13C COSY and DEPT experiments.

Chlorogentisylquinone, a new neutral sphingomyelinase inhibitor, produced by a marine fungus.

Chlorogentisylquinone, a new inhibitor of neutral sphingomyelinase activity, was purified from the culture broth of a fungal strain FOM-8108 isolated from a marine environment by solvent extraction, silica gel chromatography and Sephadex LH-20 chromatography. Its chemical structure was elucidated by spectroscopic studies including 1H, 13C, DEPT, HMQC and HMBC NMR experiments. Chlorogentisylquinone inhibited neutral sphingomyelinase activity of rat brain membranes with an IC50 value of 1.2 microM.

Structural elucidation of two [1.4]metacyclophanes isomers by 2D NMR analysis

The acid-catalysed condensation of diethyl benzene-1,3diyldioxy diacetate and p-methyl-benzaldehyde provides an hydroxy-derivatised resorcinarene or [1.4]metacyclophane as a mixture of two isomeric compounds ( IIa and IIb), which were separated by recrystallisation and column chromatography. Under homogeneous as well as under heterogeneous acidic conditions, we obtained the same isomer ( IIa) as the main product of the reaction. The 1H NMR assignments were made with the help of 2D COSY-45 and HC COSY. The 13C-multiplicities were established by carrying out DEPT experiments whereas the stereochemistry has been determined by a series of NOESY and NOE difference experiments. The results revealed that IIa isomer has a cis– trans– trans configuration (in a chair like conformation) and IIb isomer has a cis– cis– cis configuration (in a boat like conformation). The spectral properties (MS, IR and UV) are also presented.

A new acylated flavonol triglycoside from Carrichtera annua.

A new acylated flavonol triglycoside, quercetin 3-O-[(6-feruloyl-beta-glucopyranosyl)-(1-->2)-beta-arabinopyran oside] -7-O-beta-glucopyranoside (1), as well as the known flavonoid quercetin, were isolated from the whole plants of Carrichtera annua. The structure of 1 was established by UV, MS, and 1D and 2D NMR spectroscopy, including DEPT, DQF-COSY, TOCSY, HSQC, HSQC-TOCSY, and HMBC experiments.

Synthesis and surface properties of new dicephalic saccharide‐derived surfactants

AbstractA new group of nonionic dicephalic saccharide amides, N‐dodecyl‐N,N‐bis[(3‐d‐gluconylamido)propyl]‐amine, N‐dodecyl‐N,N‐bis[(3‐d‐glucoheptonylamido)propyl]‐amine, and N‐alkyl‐N,N‐bis[(3‐lactobionylamido)propyl]amines (alkyl: n‐C12H25′n‐C16H33′, n‐C18H37) were synthesized and characterized. Their structure and purity were confirmed by means of 1H and 13C nuclear magnetic resonance analysis and electrospray ionization mass spectrometry. Carbon spectra were verified using a DEPT experiment. The surface and interfacial properties such as critical micelle concentration (CMC), standard free energy of micellization, ΔGCMC, surface excess concentration, ΓCMC, and surface area demand per molecule, ACMC, were determined. The tertiary nitrogen atom seems to have a surprising effect on surfactnat packing at the interface.

Buzonamine, a new alkaloid from the defensive secretion of the millipede, Buzonium crassipes.

GC-MS analysis of the defensive secretion from the millipede Buzonium crassipes showed three volatile components, beta-pinene (35%), limonene (6%) and a new alkaloid, buzonamine (59%). Buzonamine had an HRMS molecular ion at m/z=221.1785 (calculated for C(14)H(23)NO, 221.1781), 14 carbons in the 13C-NMR and 23 hydrogens by SFORD, DEPT and APT experiments. All distinct 1H nuclei were assigned to 13C resonances with 2D 1H-13C COSY data, and the final structure was determined by 1H-1H COSY, 1H-13C HMBC and nOe experiments. Buzonamine contains four rings including an epoxy group and a tertiary nitrogen. beta-Pinene, limonene or buzonamine, kept the mound nesting ant, Formica obscuripes, from eating mealworms (Tenebrio molitor) treated with 1mg of the chemical. A 150mg millipede expels 4mg of secretion.

Koelpinin- A, B and C — three triterpenoids from Koelpinia linearis

Three new triterpenoids, designated as koelpinin - A, B and C and characterised as 28- nor-lup-12,17-dien-3β,16α-diol,3β-acetoxy-28- nor-lup-12,17-dien-16α-ol and 28- nor-lup-12,17-dien-3β-ol-16-one, respectively, together with 30- nor-lup-3β-ol-20-one, taraxeryl acetate and germanicol, were isolated, from the aerial parts of Koelpinia linearis. 13 C -NMR shifts were assigned after performing APT and DEPT experiments.

Synthesis and characterization of poly(ethylene-co-norbornadiene)

The norbornadiene/ethylene copolymerization was studied using [Ph2C(Ind)(Cp)ZrCl2] and [Cp2ZrCl2] catalysts in the presence of methylaluminoxane as a cocatalyst. The polymerizations were carried out using a semiflow method, and the comonomer was charged batchwise into the reactor. Polymerizations were run at 60°C at an ethylene pressure of 2.5 bar. The activities of both catalysts decreased when the norbornadiene/ethylene ratio in the reaction increased. The structural characterization of the copolymer was performed by DEPT and 1H-13C 2D NMR experiments. The copolymerization of norbornadiene was shown to occur via both double bonds of norbornadiene. The polymers with high norbornadiene content were amorphous and transparent.

Isolation, identification, and antifungal activity of a macrolide antibiotic, oligomycin A, produced by Streptomyces libani

The antibiotic As1A, strongly inhibitory to Phytophthora capsici Leonian in vitro and in vivo, was isolated from the broth culture of Streptomyces libani Baldacci & Grein using various chromatographic procedures. The molecular formula of the antibiotic As1A was deduced to be C45H74O11 (M+H, m/z 791.5307) by high resolution fast atom bombardment - mass spectroscopy. The analysis of 1H-NMR (nuclear magnetic resonance) and 13C-NMR spectroscopy, DEPT experiment, and two-dimensional NMR spectral data revealed that the antibiotic is a macrolide antibiotic having a 26-membered alpha, beta-unsaturated macrolactone ring with a conjugated diene fused to a bicyclic spiroketal. Based on the comparison of NMR data and other chemical properties, the antibiotic As1A turned out to have the same structure as oligomycin A. The antibiotic As1A showed a high level of inhibitory activity against Botrytis cinerea Pers.: Pers., Cladosporium cucumerinum Ellis & Arthur, Colletotrichum lagenarium (C.P. Robin) Berkhout, Magnaporthe grisea (Herb.) Barr, and P. capsici, ranging from 3 to 5 µg·mL-1 of MICs. However, no antimicrobial activity was found against yeasts and bacteria. In further evaluation under greenhouse conditions, developments of the Phytophthora disease, anthracnose, and leaf blast were markedly inhibited on pepper (Capsicum annuum L. cv. Hanbyul), cucumber (Cucumis sativus L. cv. Baekrokdadaki), and rice (Oryza sativa L. cv. Nakdong) plants by treatments with the antibiotic As1A, respectively. Control efficacies of the antibiotic As1A against these plant diseases were in general similar to those of metalaxyl, chlorothalonil, and tricyclazole. The antibiotic As1A did not show any phytotoxicity on pepper, cucumber, and rice plants even at 500 µg·mL-1.Key words: Streptomyces libani, oligomycin A, antifungal activity, plant disease control.