Chemical constituents of Piper betle Linn. (Piperaceae) roots

Column chromatography of the alcoholic extract of Piper betle roots furnished aristololactam A-II and a new phenyl propene, characterized as 4-allyl resorcinol, while the petroleum-ether extract yielded a diketosteroid, viz. stigmast-4-en-3,6-dione. All these compounds were characterized by spectroscopic means. Isolation of these compounds from this source is being reported here for the first time.     

1H and 13C NMR assignments and X-ray structures for three monocyclic benzoannelated dilactam polyethers

Three monocyclic polyether dilactams, 17,18-dihydro-5H, 9H-dibenzo[e,n]1,4,10,7,13trioxadiazacyclopentadecine-6,10(7H,11H)-dione (1); 9,10,20,21-tetrahydro-5H, 12H-dibenzo[e,q]1,4,10,13,7,16tetraoxadiazacyclooctadecine-6, 13(7H,14H)-dione (2); and 6,7,9,10-tetrahydro-16H, 20H-dibenzo[h,q]1,4,7,13, 10,16tetraoxadiazacyclooctadecine-17, 21(18H,22H)-dione (3) were isolated during the synthesis of several benzoannelated cryptands. The complete assignments of the 1H and 13C NMR spectra of 1, 2 and 3 in CDCl3 were made using gCOSY, gHMBC, gHMQC, HMQC, HSQC, and NOESY 1D techniques. The ortho (H2) benzene protons show significant downfield shifts (1.16-1.43 ppm) that are consistent with an exodentate orientation for the amide carbonyl groups. The X-ray crystal structures of 1, 2 and 3 show that the carbonyl groups adopt an exodentate conformation in the solid state.     

Preparation and fungitoxicity of 3,6-dichloro-and 3,6-dibromo-8-quinolinols

Summary 3,6-Dichloro- and 3,6-dibromo-8-quinolinols were prepared by direct halogenation of 8-nitroquinoline by N-halosuccinimide in acetic acid or by halogenation of the corresponding 6-halo-8-nitroquinoline prepared via aSkraup reaction. The nitro group was reduced to amino and the amine was hydrolyzed to the phenol in 70% sulfuric acid at 220°C. The fungitoxicity of 3,6-dichloro- and 3,6-dibromo-8-quinolinols, as well as intermediates in their preparation, againstAspergillus niger, Aspergillus oryzae, Myrothecium verrucaria, Trichoderma viride, andMucor cirinelloides was determined. 3,6-dichloro-8-quinolinol is the most fungitoxic analogue of this class of compounds observed to date.

---

Herstellung und Fungitoxizität von 3,6-Dichlor- und 3,6-Dibrom-8-chinolinen

Zusammenfassung 3,6-Dichlor- und 3,6-Dibrom-8-chinoline wurden durch direkte Halogenierung von 8-Nitrochinolin mit N-Halogensuccinimid in Essigsäure oder durch Halogenierung der entsprechenden nachSkraup synthetisierten 6-Halogen-8-nitrochinoline hergestellt. Die Nitrogruppe wurde zum Amin reduziert und die Aminofunktion in 70% iger Schwefelsäure bei 220°C zum Phenol hydrolysiert. Die Fungitoxizität der 3,6-Dichlor- und 3,6-Dibrom-8-chinoline und jene der bei ihrer Herstellung auftretenden Zwischenstufen gegenAspergillus niger, Aspergillus oryzae, Myrothecium verrucaria, Trichoderma viride undMucor cirinelloides wurde bestimmt. 3,6-Dichlor-8-chinolin ist der derzeit stärkste bekannte fungitoxische Vertreter dieser Substanzklasse.

     

The reaction of 3,6-di-tert-butyl-1,2-benzoquinone and 3,6-di-tert-butylcatechol withtert-butyl hydroperoxide

Reaction of 3,6-di-tert-butyl-1,2-benzoquinone and 3,6-di-tert-butylcatechol withtert-butyl hydroperoxide in aprotic solvents leads to the generation of semiquinone (SQ^.H), alkylperoxy (ROO^.), and alkyloxy radicals. The reaction of SQ^.H and ROO^. produces 2,5-di-tert-butyl-6-hydroxy-1,4-benzoquinone, 3,6-di-tert-butyl-1-oxacyclohepta-3,5-diene-2,7-dione, and 2,5-di-tert-butyl-3,6-dihydroxy-1,4-benzoquinone. The radical generated from solvent attacks SQ^.H at position 4 with C−C bond formation. 4-Benzyl-2,5-di-tert-butyl-6-hydroxycyclohexa-2,5-diene-1-dione produced in this way is transformed into 4-benzyl-3,6-di-tert-butyl-1,2-benzoquinone under the reaction conditions. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 943–946, May, 1999.     

Unambiguous structural characterization of hydantoin reaction products using 2D HMBC NMR spectroscopy

Data from two-dimensional (2D) NMR experiments were used to identify the reaction products resulting from the opening of pyroglutamates with isocyanates or thioisocyanates. The reaction has the potential to produce compounds that would have very similar one-dimensional proton ((1)H) or carbon-13 ((13)C) NMR spectra. Careful analysis of (1)H--(1)H COSY, (1)H--(1)H NOESY, and HMBC data, including chemical shifts and coupling constants, were used to distinguish correctly between carbamoyl-2-pyrrolidinone, hydantoin, and perhydro-1,3-diazepine-2,4-dione type structures that could result from this reaction. This work describes their preparation and subsequent identification using 2D NMR spectroscopy, and includes complete (13)C assignments of the reaction products. The 2D NMR techniques and analysis described here can be applied successfully to other synthetic reactions with the potential to produce isomeric products.     

Novel Synthesis of 2-(2-(3-Hydroxy-5-oxo-4-phenylthiophen-2(5H)-ylidene)-2-phenylacetamido)propanoic Acid Analogues and Their Anti-Inflammatory Properties

This article describes the reaction of 3,6-diphenyl-thieno[3,2-b]furan-2,5-dione 1 with different amino acids 2a–j in glacial acetic acid which afforded the 2-(2-(3-hydroxy-5-oxo-4-phenylthiophen-2(5H)-ylidene)-2-phenylacetamido)propanoic acid analogues 3a–j and also describes the reaction of 3,6-diphenyl-thieno[3,2-b]thiophene-2,5-dione 4 with different amino acids 5a–e in acidic medium to give 2-(2-(3-mercapto-5-oxo-4-phenylthiophen-2(5H)-ylidene)-2-phenylacetamido)propanoic acid analogues 6a–e. All the compounds have been screened for their anti-inflammatory activity against the carrageenan induced rat paw edema in albino rats. In the primary screening, some of the compounds exhibited appreciable activity.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Assignments of 1H and 13C NMR spectral data for ondansetron and its two novel metabolites, 1-hydroxy-ondansetron diastereoisomers

Assignments of 1H and 13C NMR chemical shifts were made by means of heteronuclear single quantum coherence (HSQC) and heteronuclear multiple bond correlation (HMBC) experiments for ondansetron, and by means of 1H-1H correlation spectroscopy (1H-1H COSY) and two-dimensional nuclear Overhauser effect spectroscopy (NOESY) experiments for two novel metabolites (M1 and M2) of ondansetron. These two metabolites were isolated for the first time from Mucor circinelloides.     

一种新的六氢嘧啶并嘧啶二酮衍生物的核磁共振分析

采用氢谱(1H NMR)、碳谱(13C NMR)、梯度场氢氢化学位移相关谱(1H-1H COSY)、梯度场质子检测异核单量子化学位移相关谱(HSQC)、梯度场质子检测异核多重键化学位移相关谱(HMBC)等多种NMR分析方法,确证了8a-对甲氧苯基-4,5-双(对氯苯基)六氢嘧啶[4,5-d]并嘧啶-2,7(1H,3H)-二酮的结构,对它的1H和13C NMR谱信号进行了归属,为其结构鉴定提供了重要依据。     

Condensation of 1,4-diacetylpiperazine-2,5-dione with aldehydes

Condensation of 1,4-diacetylpiperazine-2,5-dione with aldehydes has been applied to the synthesis of albonoursin and unsymmetrical 3,6-diarylidenepiperazine-2,5-diones. The reaction has been extended to 1,4-diacetyl-3,6-dimethylpiperazine-2,5-dione, which gives derivatives of 2-methyl-3- phenylserine. The mechanism and stereochemistry are discussed; cis 1-acetyl-3-isobutylidene- piperazine-2,5-dione has been isolated.     

A new oleanane glycoside from the roots of Astragalus caprinus

A novel oleanane-type triterpene saponin (1) together with two known molecules, soyasapogenol B and astragaloside VIII were isolated from the roots of Astragalus caprinus. Their structural elucidation was performed mainly by 2D NMR techniques (COSY, TOCSY, NOESY, HSQC, HMBC) and mass spectrometry. Compound 1 was determined as 3-O-[alpha-L-rhamnopyranosyl-(1 --> 2)-beta-D-glucuronopyranosyl]-22-O-beta-D-apiofuranosyl-soyasapogenol B.     

Boldenone, testosterone and 1,4-androstadiene-3,17-dione determination in faeces from horses, untreated and after administration of androsta-1,4-diene-3,17-dione (boldione)

Faeces, which could be a potential alternative medium for doping control, have been used for the detection of 1,4-androstadiene-3,17-dione administration to the horse. Semi-quantitative analyses of 1,4-androstadiene-3,17-dione, testosterone, 17alpha- and 17beta-boldenone have been conducted in pre- and post-administration faeces, and in controls (untreated stallions, geldings and mares). Sample preparation comprised diethyl ether extraction, lipid removal, HPLC purification and derivatisation. 1,4-Androstadiene-3,17-dione, testosterone, 17alpha- and 17beta-boldenone were analysed by GC-EI/MS/MS. Quantitative limits of detection were 0.1 ng/g for 1,4-androstadiene-3,17-dione, and 0.025 ng/g for testosterone, 17alpha- and 17beta-testosterone. In post-administration samples from geldings and mares, peak levels of 1,4-androstadiene-3,17-dione, 17alpha-, 17beta-boldenone and testosterone were attained 24 h after administration. In untreated geldings and mares (in di- or anoestrus), 17alpha- and 17beta-boldenone and testosterone were not detected. Faeces from females in oestrus had detectable levels of boldenone isomers and testosterone. 1,4-Androstadiene-3,17-dione was undetectable in faeces collected from untreated horses, but the presence of this androgen was recently reported in faeces from untreated swine and it would therefore be advisable to check for its possible presence in a larger number of individual faecal samples.     

Antimutagenic constituents from the thorns of Gleditsia sinensis

Antimutagenic activity-guided fractionation of an extract prepared from the thorns of Gleditsia sinensis LAM. led to the isolation of one triterpenoid and four steroids, which were identified as D:C-friedours-7-en-3-one (1), stigmast-4-ene-3,6-dione (2), stigmastane-3,6-dione (3), stigmasterol (4), and beta-sitosterol (5). Triterpenoid 1 was found for the first time in a natural source and the steroids 2-5 were first isolated from this plant. Stigmasterol was the most active antimutagen, showing 51.2% and 64.2% reduction of the induction factor against the mutagens MNNG and NQO, respectively, in the SOS chromotest. Some NMR data of the steroids 2 and 3 obtained have to be revised.     

Studies of the Photochemical Degradation Kinetics of BaP on Different Substrates: Formation of Oxygenated Compounds

Abstract

The rate constant for BaP decomposition induced by exposure to UV rays and rate constants for BaP1,6; 3,6; 6,12 diones formation were determined. Experiments were conducted by depositing the BaP on clean glass fiber-filter and on airborne paniculate collected by filter. The BaP half-life appears to be positively correlated with filter loading and airborne particulates protect BaP from UV degradation. Our results suggest that BaP1,6dione, BaP3,6dione, BaP6,12dione are not the main by-products of BaP photodegradation induced by UV.     

Structure elucidation of a new friedelane triterpene from the mangrove plant Hibiscus tiliaceus

From the stem and bark of the mangrove plant Hibiscus tiliaceus, a new friedelane-type triterpene named 27-oic-3-oxo-28-friedelanoic acid (1) together with eight known triterpenoids involving five friedelane-type derivatives was isolated. The structure of 1 was determined by extensive 2D NMR (DQF-COSY, HMQC, HMBC, and NOESY) data analyses. All the compounds were obtained from mangrove plants for the first time.     

Synthesis and properties of σ–π conjugated alternating polymers consisting of carbazole and organosilicon units

We have synthesized novel σ–π conjugated polymers with an alternating organosilanylene and π‐electron system, intending to utilize them for hole‐transporting materials of electroluminescent (EL) devices. 3,6‐Di(lithioethynyl)carbazoles were co‐polymerized with organodichlorosilanes to give the corresponding polymers with molecular weights of M_W = 2000–5000. Another type of polymer with a thienylene unit was also synthesized by the nickel‐catalyzed reaction of the di‐Grignard reagent of 1,2‐bis[2‐(5‐bromothienyl)]tetraethyldisilane with 3,6‐dibromocarbazole, the molecular weight being M_n = 3100. The EL devices with a double‐layer system composed of tris(8‐quinolinolato)aluminum(III) and the present polymers as the emitting‐electron‐transporting and hole‐transporting layers, respectively, emit green EL with a maximum intensity of the order of 10³ cd m^?2. Of these, the device with the thienylene–carbazole polymers exhibited the highest luminance of 1480 cd m^?2. Copyright © 2001 John Wiley & Sons, Ltd.     

Novel and stereoselective asymmetric synthesis of an amino sugar analogue, furanodictine A

A novel and efficient strategy is described for the asymmetric synthesis of the first 3,6-anhydrosugar to be isolated from natural sources, furanodictine A. The synthetic process is based on requisite stereodefined manipulation of the functionalized amino alcohol obtained through nucleophilic addition of vinyl Grignard reagent to the aminal incorporating the d-arabinofuranose-derived skeleton in a complete stereoselective manner.     

Self‐Assembly of 3,6‐Bis(4‐triazolyl)pyridazine Ligands with Copper(I) and Silver(I) Ions: Time‐Dependant 2D‐NOESY and Ultracentrifuge Measurements

Two 3,6‐bis(R‐1H‐1,2,3‐triazol‐4‐yl)pyridazines (R=mesityl, monodisperse (CH₂ CH₂O)₁₂CH₃) were synthesized by the copper(I)‐catalyzed azide–alkyne cycloaddition and self‐assembled with tetrakis(acetonitrile)copper(I) hexafluorophosphate and silver(I) hexafluoroantimonate in dichloromethane. The obtained copper(I) complexes were characterized in detail by time‐dependent 1D [¹H, ¹³C] and 2D [¹H‐NOESY] NMR spectroscopy, elemental analysis, high‐resolution ESI‐TOF mass spectrometry, and analytical ultracentrifugation. The latter characterization methods, as well as the comparison to analog 3,6‐di(2‐pyridyl)pyridazine (dppn) systems and their corresponding copper(I) and silver(I) complexes indicated that the herein described 3,6‐bis(1H‐1,2,3‐triazol‐4‐yl)pyridazine ligands form [2×2] supramolecular grids. However, in the case of the 3,6‐bis(1‐mesityl‐1H‐1,2,3‐triazol‐4‐yl)pyridazine ligand, the resultant red‐colored copper(I) complex turned out to be metastable in an acetone solution. This behavior in solution was studied by NMR spectroscopy, and it led to the conclusion that the copper(I) complex transforms irreversibly into at least one different metal complex species.     

Two isomeric epoxysitosterols from Rhododendron formosanum: 1H and 13C NMR chemical shift assignments

1H and 13C NMR assignments of the two isomeric epoxysitosterols, 5,6 alpha-epoxy-5 alpha-stigmastan-3 beta-ol (1) and 5,6 beta-epoxy-5 beta-stigmastan-3 beta-ol (2), isolated from the leaves of Rhododendron formosanum Hemsl were achieved by 1D and 2D techniques such as DEPT, HMBC, HMQC, COSY and NOESY.     

NMR assignments and X-ray diffraction spectra for two unusual kaurene diterpenes from Erythroxylum barbatum

The structural characterization of two new, unusual kaurene diterpenes isolated from roots of Erythroxylum barbatum is described. 1D NMR and several 2D shift-correlated NMR pulse sequences (1H,1H-COSY, HMQC, HMBC and NOESY) were used for structure elucidation and the unambiguous 1H and 13C chemical shifts assignments. Single crystal X-ray diffraction analysis was also used to confirm the final relative configuration of the compounds possessing the C-20 methyl and the CH2-15 methylene groups in cis-orientation.     

Complete assignments of 1H and 13C NMR data for rings A,B-seco limonoids from the seed of Aphanamixis polystachya

Seven rings A,B-seco limonoids 1-7 were isolated from the EtOH extract of the seed of Aphanamixis polystachya. Their structures were identified as rohituka-7 (1), dregeana-1 (2), rohituka-15 (3), Tr-B (4), rohituka-3 (5), rohituka-5 (6), and rohituka-14 (7) by MS and NMR spectroscopy. The complete assignment of proton and carbon signals was achieved by 1D and 2D NMR experiments including DEPT, HSQC, 1H--1H COSY, HMBC, and NOESY.