Iridoids and phenylethanoid from Pedicularis kerneri Dalla Torre growing in Dolomites,Italy

In this study, we report the first phytochemical analysis of polar fraction of Pedicularis kerneri Dalla Torre growing in Dolomites, Italy. Several iridoid glucosides were isolated, namely aucubin (1), monomelittoside (2), plantarenaloside (3), euphroside (4), mussaenosidic acid (5) and 8-epiloganic acid (6), showing a composition in accordance with previous study on this genus. The studied samples, collected from Dolomites, presented a chemotype already recognised in species from North America, characterised by euphroside (4) and aucubin (1) as main components, but the main character was the presence of monomelittoside (2) never reported in this genus. The identification of verbascoside (7), leucosceptoside A (9) and echinacoside (10) complete the systematic framing of this species since is ascertained the co-occurrence of phenylethanoid glycosides with iridoids in Lamiales species.     

Correlated and idempotent Dirac first-order density matrices with identical diagonal Fermion density: a route to extract a one-body potential energy in TDDFT

After a brief introduction to the use of the idempotent Dirac first-order density matrix (DM), its time-dependent generalization is considered. Special attention is focused on the equation of motion for the time-dependent DM, which is characterized by the one-body potential V(r, t) of time-dependent density functional theory. It is then shown how the force –∇ V(r, t) can be extracted explicitly from this equation of motion. Following a linear-response treatment in which a weak potential V(r, t) is switched on to an initially uniform electron gas, the non-linear example of the two-electron spin-compensated Moshinsky atom is a further focal point. We demonstrate explicitly how the correlated DM for this model can be constructed from the idempotent Dirac DM, in this time-dependent example.     

Unusual molecular pattern in Ajugoideae subfamily: the case of Ajuga genevensis L. from Dolomites

We analysed the ethanolic extract from Ajuga genevensis L. (Lamiaceae) growing in Dolomites, part of Italian Alps. Three new compounds for this species were identified: rosmarinic acid (1), oleanolic acid (2) and maslinic acid (3), representative of two different classes of chemical compounds (phenylpropanoids and pentacyclic triterpenes). A. genevensis resulted to be a valuable source of these compounds endowed with interesting biological activities (i.e. antioxidant, neuroprotective, anti-inflammatory, antiproliferative). The recognition of compounds (1), (2) and (3) may also confirm the ethnomedicinal uses of this plant. From a chemotaxonomical point of view, it is worth noting that iridoids were not evidenced in this accession. Iridoids are considered chemotaxonomic marker in Lamiales, and, in contrast with a previous study on this species, the presence of aucubin was not confirmed. In addition, the presence of large amounts of rosmarinic acid (1) was unexpected for a species that does not belong to subfamily Nepetoideae.     

Synthesis and characterization of two cobalt(II) complexes based on 4,6-bis(2-pyridyl)-1,3,5-triazin-2-ol

Two cobalt(II) complexes based on 4,6-bis(2-pyridyl)-1,3,5-triazin-2-ol (HOBPT), [Co₃(OBPT)(μ³?OH)(SO₄)₂(H₂O)₃]·2H₂O (1) and [Co(OBPT)₂]·2H₂O (2) were obtained. Single-crystal X-ray diffraction analyses indicate that 1 is a two-dimensional (2D) structure and the ligand adopts mono/bis-bidentate coordination; this coordination mode of this ligand was never found before. Magnetic properties of 1 have been studied, showing that 1 is a spin canted belt. Much different from 1, 2 is a discrete structure with tridentate ligand with its hydroxyl group deprotonated but uncoordinated. Lattice water molecules in 2 link to four-membered water clusters, which linked the [Co(OBPT)₂] to 1-D chains along the b axis.     

ORGANISCHE PHOSPHORVERBINDUNGEN 80 HERSTELLUNG VON TRIAZOLYLMETHYL-PHOSPHONATEN UND VON TRIAZOLYL-METHYLPHOSPHONIUMSALZEN UND DEREN VERWENDUNG IN DER WITTIG-HORNER REAKTION

Abstract

Attempts to prepare 1H-1,2,4-triazol-1-ylmethylphosphonates (4 and 5) by a Mannichtype reaction or by transesterification of 1-hydroxymethyl-1H-1,2,4-triazol 1 with tertiary phosphites failed. On the other hand 4 and 5 are obtained by a Michaelis-Becker reaction from 1-chloromethyl-1H-1,2,4-triazol 3 and sodium phosphites in high yield. The Michaelis-Arbuzov reaction is less suited for the preparation of 4 and 5. 3 is obtained in good yield as a water clear liquid, b.p. 52–54°C/0.2 torr, from the interaction of 1 with thionyl chloride followed by treatment with a base. On standing at 0° or 20°C it decomposes within hours and yields the unsymmetrical methylen-bis(triazol) 3a in addition to other products. However an acetonitrile solution of 3 is stable for months. Heating this solution with tertiary phosphines gives triazolylsubstituted phosphoniumsalts 6 to 8. The Wittig-Horner reaction with 4 to 6 gives the olefinically substituted triazols 9–12 as a Z/E mixture in high yield. Alkylation of 4 with methyl-and ethyl iodide gives the corresponding alkylated diethyl-1H-1,2,4-triazol-1-yl-ethyl-1-and-propyl-1-phosphonates 14 and 15 which on hydrolysis with HCI yield 1H-1,2,4-triazol-1-yl-ethyl-1-and propyl-1-phosphonic acids 17 and 18, respectively. Hydrolysis of 4 gives the unsubstituted 1H-1,2,4-triazol-1-ylmethyl-phosphonic acid, 16.     

Spectral Assignment of Phenanthrene Derivatives Based on 6H-Dibenzo[C,E][1,2] Oxaphosphinine 6-Oxide by NMR and Quantum Chemical Calculations

Abstract

Organophosphorus compounds such as 6H-dibenzo[c,e][1,2]oxaphosphinine 6-oxide (DOPO, 1) and its derivatives are important and versatile compounds for a broad field of applications. However, a thorough spectral assignment is often subordinate to its chemical properties. This article presents and unambiguously attributes the ¹H and ¹³C NMR spectra of DOPO (1), selected products yielded from the Atherton–Todd reaction (2–4), DOPO-HQ (5) as well as sulfur derivatives (6–7) via a set of 1D- and 2D-NMR experiments. The complex P-C and P-H coupling patterns are discussed and compared with the derivatives possessing different chemical environments around the phosphorus atom. In addition, we compared our results with density functional theory calculations. Even though the prediction of NMR data of organophosphorus compounds via molecular modeling is limited, this study presents a method that yields good results for this class of heterocycles. This knowledge should help to quickly assign NMR spectroscopic data of other DOPO (1) derivatives and can be extrapolated to organophosphorus compounds in general.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental resource: NMR Spectra of Compounds 1-7 (Figures S1 - S15).     

Synthesis and electropolymerization of EDOT modified 1,3-bis(5-methyl-2-thiazolylimino)isoindolinato palladium(II) complex for electrochemical detection of hydrogen peroxide

1,3-Bis(5-methyl-2-thiazolylimino) isoindoline derivative (EDOT-BTI) containing an electropolymerizable group is prepared using the Linstead method. According to this two-step method phthalonitrile derivative EDOT-Pht is converted to 1,3-diiminoisoindoline EDOT-DII first then EDOT-DII is reacted with 2-amino-5-methylthiazole in ethanol during 5 day reflux. Palladium(II) complex (EDOT-PdBTI) of EDOT-BTI is synthesized in benzene using [Pd(PhCN)₂Cl₂] as the palladium(II) precursor and triethylamine as auxiliary base. In order to show the H₂O₂ sensing properties of EDOT-PdBTI, electrochemical characterizations of EDOT-BTI and EDOT-PdBTI are performed and then modified glassy carbon electrode is constructed with electropolymerization of EDOT-PdBTI. GCE/PEDOT-PdBTI shows a wave at 0.215 V. With increasing H₂O₂ concentration, this wave shifts to ?0.075 V. A linear range is observed between 0.72 and 13.6 μmol dm^?3 with a limit of detection of 0.21 μmoldm^?3 and sensitivity of 0.0153 mV μmol^?1 dm^?3. These data illustrate possible use of the electrode as a potentiometric H₂O₂ sensor.     

Reaktionen von Arylidentetralonen mit Cyanessigsäurederivaten

Some reactions of 2-arylidene-tetralones1 with cyanoacetamide and alkyl cyanoacetates under basic conditions are described. From1 and cyanoacetamide the benzo[h]quinoline-2-ones3 are formed by cyclization with the carboxamide group, the intermediate addition product2 is not isolable. The addition products5 from1 and cyanoacetates however are crystalline compounds, which are converted by cyclization via the ester group to lactones6, and then oxidized to7. The expected products from a cyclization with the cyanide group are not found. The possibility of this cyclization path is shown by reaction of5 to the tetracyclus10 whose structure is found to be analogue to that of the reaction product from11-obtained by reaction from1 and malononitrile-to12.

3. Mitt.:H.-H. Otto, O. Rinus undH. Schmelz, Synthesis1978, 681.     

Synthesis of an Advanced Precursor of Demethoxyviridin

The synthesis of a potential precursor 3 to demethoxyviridin (1b) is described. The centerpiece of this strategy was the conversion of the previously described dibromoolefin 6 to the masked alkyne β-hydroxyaldehyde 5 in a single step. Further elaboration then produced the alkyne oxazole 4, which on thermolysis, followed by in situ tautomerization and silylation, led directly to 3.

Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for full experimental and spectral details.     

A new oxathiolane from Enterobacter cloacae

Enterobacter cloacae is a versatile bacterial species inhabiting a wide variety of niches and is capable of metabolising a wide variety of substances as energy resources. The fermentation culture of this bacterial species has successfully yielded one new compound, Rimboxa (1) and three known compounds, i.e. indole-3-carboxaldehyde (2), indole-3-acetic acid (3) and 3,4-di-t-butylaniline (4). Rimboxa (1) is shown to possess the 1,2-oxathiolane core structure. 3,4-Di-t-butylaniline (4) is isolated for the first time from a natural resource. These compounds were isolated and characterised using extensive chromatographic and spectroscopic methods, and were subjected to cytotoxicity evaluations.     

Three-block bi-focal PLS (3BIF-PLS) and its application in QSAR

When X and Y are multivariate, the two-block partial least squares (PLS) method is often used. In this paper, we outline an extension addressing a special case of the three-block (X/Y/Z) problem, where Z sits "under" Y. We have called this approach three-block bi-focal PLS (3BIF-PLS). It views the X/Y relationship as the dominant problem, and seeks to use the additional information in Z in order to improve the interpretation of the Y-part of the X/Y association. Two data sets are used to illustrate 3BIF-PLS. Example I relates to single point mutants of haloalkane dehalogenase from Sphingomonas paucimobilis UT26 and their ability to transform halogenated hydrocarbons, some of which are found as organic pollutants in soil. Example II deals with soil remediation capability of bacteria. Whole bacterial communities are monitored over time using "DNA-fingerprinting" technology to see how pollution affects population composition. Since the data sets are large, hierarchical multivariate modelling is invoked to compress data prior to 3BIF-PLS analysis. It is concluded that the 3BIF-PLS approach works well. The paper contains a discussion of pros and cons of the method, and hints at further developmental opportunities.     

Prediction of paper permanence by accelerated aging II. Comparison of the predictions with natural aging results

Accelerated aging tests are credible and useful to predict paper permanence only if such tests can be shown to correlate with natural aging. In the first part of this study, a kinetic model was developed based on the accelerated aging results. In this report, we have shown that this kinetic model can indeed predict the natural aging results of lignin-free sheets with a statistical confidence. This is the first quantitative comparison of accelerated aging with natural aging.     

A green synthetic process for the preparation of water-soluble drugs: pegylation of menadiol and podophyllotoxin

Abstract

Pegylation of drugs is a frequently employed strategy used to improve the pharmacokinetics and pharmacodynamics of drugs. Despite this, the virtues of pegylation as a green synthetic approach to enhance the water solubility of drugs has not been discussed. Using two well-known active pharmaceutical ingredients, menadiol sodium diphosphate (1) and the semisynthetic natural product, etoposide phosphate (3), green metrics for the processes of pegylation versus phosphorylation are presented and discussed. Menadiol (2) was prepared by an ultrasound mediated reduction of menadione (9). In a study done by the National Cancer Institute, PEG podophyllotoxin 12 was screened for activity against 60 different human cancer cell lines and the desired anticancer properties of podophyllotoxin (5) were retained. As podophyllotoxin (5) is a natural product, the concept of “green drugs” is espoused.     

N-Alkylamides from Piper longum L. and their stimulative effects on the melanin content and tyrosinase activity in B16 melanoma cells

Abstract

Piper longum L., known as long pepper, is an edible and medicinal plant used as spice and for the treatment of stomach disease and analgesia in traditional Chinese medicine. N-Alkylamides are the major secondary metabolites in this plant. Sixteen known N-alkylamides were isolated from P. longum. Their structures were established on the basis of spectroscopic data and comparison to reported literatures. Among them, five compounds were isolated from this plant for the first time. Ethanol extract, compounds 1, 2, 3, 7 and 11 exhibited potent ability to increase the melanin content and weak stimulative effect on the tyrosinase activity in a concentration-dependent manner. Moreover, compound 2 also presented strong capacity to increase the tyrosinase activity in a concentration-dependent manner. These results indicated that P. longum might be a good natural source of lead compound for skin disorder diseases.     

SELECTIVE ALKYLATION/ACYLATION OF DI- OR TRIANIONS: EXPEDITIOUS DERIVATIZATION OF ENDOTHELIN ANTAGONISTS[1]

ABSTRACT

Sitaxsentan sodium (1, TBC11251Na) is an ET_A selective endothelin antagonist under clinical development for pulmonary arterial hypertension and congestive heart failure. Second generation compounds, as exemplified by TBC2576 (2) are currently under development in our laboratories. To rapidly access analogs of 1 and 2, a route was developed for the selective alkylation or acylation of the corresponding di- or trianions derived from these two highly functionalized compounds. We report here on this straightforward, yet effective, procedure consisting of treating the di- or trianions with an excess amount of electrophiles, followed by a rapid quench. In this manner, selective alkylation or acylation of 1 and 2 was achieved with satisfactory yields.     

Chemical composition and antioxidant activity of a polar extract of Thymelaea microphylla Coss. et Dur.

Thymelaea microphylla Coss. et Dur. (Thymelaeaceae) is a rare medicinal plant endemic to Algeria. In order to continue our studies on this species, herein we report the isolation and characterisation of 20 compounds from a hydroalcoholic extract (EtOH–H₂O 7:3) of the aerial parts. They include monoterpene glucosides (1–3), phenolic acid derivatives (4, 8 and 9), phenylpropanoid glucosides (5 and 6), flavonoids (7, 10 and 11), a benzyl alcohol glucoside (12), ionol glucosides (13–16), lignans (17–19) and a bis-coumarin (20). All the structures were elucidated by spectroscopic methods including 1D and 2D NMR experiments, as well as ESI-MS analysis. Moreover, the extract of T. microphylla showed a significant and concentration-dependent free radical-scavenging activity in vitro, correlated to the presence of phenolic and chlorogenic acid derivatives (8, 9 and 4).     

PHOSPHORORGANISCHE VERBINDUNGEN 1171, EINE NEUE METHODE ZUM NACHWEIS DER FUNKTIONELLEN GRUPPEN: OH,NH2 UND SH DURCH AUSLOSUNG VON FLUORESZENZ

Abstract

Covalently with a fluorescence support linked nitroarylester groups quench the fluorescence. The substitution of the fragment with the quenching group by an other functional group initiates fluorescence. If this substitution reaction is chemoselective, a reagent for the selective detection of a special functional group is available.

The non fluorescent compounds 1a and 1b are OH-(resp. F^(-)) selective; the compounds 5 and 7 are NH-selective and the compounds 8 and 9 are SH-selective. Dansyl-nitroimidazolide 7a discriminates between neutral and basic α-amino acids.     

Amberinone,a new guaianolide from Amberboa ramosa

The Amberboa is a medicinally important genus present in the family Asteraceae; members of this genus are mainly distributed in Pakistan and India. It has been used in different systems of traditional medicines for different diseases. Amberinone (1), a new sesquiterpene lactone, has been isolated from the ethyl acetate (EtOAc) soluble fraction of Amberboa ramosa together with chrysin (2), quercitine (3), eriodictyol (4) and keamferol (5). This is the first report of these compounds from this species. The structures of the isolated compounds have been elucidated by 1D and 2D ¹H ¹³C NMR spectroscopy.     

Zur Synthese von 4-Aryl-5,6-dihydro-benzo[h]chinolinen

A new route to the benzo[h]quinoline system3 byMichael-addition of malononitrile to 2-arylidene-1-tetralones1 is presented. The mechanism of this reaction is elucidated by isolation of the intermediate 4H-naphtho[1,2—b]-pyrane2 and its reaction to3. The reaction is proposed to be a sequence of addition, cyclisation,Dimroth-rearrangement and disproportionation.

1. Mitt.:H.-H. Otto, Arch. Pharm. [Weinheim]307, 444 (1974).     

Theoretical and Quantitative Structural Relationship Studies of Electrochemical Properties of the Nanostructures of Cis-Unsaturated Thiocrown Ethers and Their Supramolecular Complexes [X-UT-Y][M@C82] (M˭Ce,Gd)

The endohedral lanthanidofullerenes, an important type of organolanthanides, are stabilized by the delocalization of the negative charges on the cages of fullerenes. Since the discovery of these classes of carbon compounds and their unusual structures and properties of these molecules, many potential applications have been suggested. Unsaturated thiocrown ethers with cis-geometry are a group of crown ethers that, in light of the size of their cavities and their conformational restriction compared to a corresponding saturated system (1–9), demonstrate interesting properties for physicochemical studies. Endohedral lanthanidofullerenes M@C_x (x = 82 and M = Ce, Gd) were introduced as a new class of the spherical fullerene group with unique properties. Formation of endohedral metallofullerenes is thought to involve the transfer of electrons from the encapsulated metal atom(s) to the surrounding fullerene cage. Two of these molecules are the Ce@C₈₂ (10) and Gd@C₈₂ (11). The supramolecular complexes of 1–9 with Ce@C₈₂ (10) and Gd@C₈₂ (11) have been shown to possess a host–guest interaction for electron transfer processes, and these behaviors have previously been reported. Topological indices have been successfully used to construct effective and useful mathematical methods for finding good relationships between structural data and the various chemical and physical properties. To establish a good structural relationship between the structures of 1–9 and M@C_x that were introduced here, an index that is represented as μ_cs was utilized. This index is the ratio of summation of the number of carbon atoms (n_c ) and the number of sulfur atoms (n_s ) to the product of these two numbers for 1–9. In this study, the relationship between this index and oxidation potential ( ^oxE₁ ) of 1–9, as well as the free energy of electron transfer (ΔG_et , by the Rehm-Weller equation) between 1–9 and 10 and 11 as [X-UT-Y][Ce@C₈₂] (12) and [X-UT-Y][Gd@C₈₂] (13) complexes, is presented.

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.