Propenyl Group Research Articles

Preparation and antiviral properties of new acyclic, achiral nucleoside analogues: 1- or 9-[3-hydroxy-2-(hydroxymethyl)prop-1-enyl]nucleobases and 1- or 9-[2,3-dihydroxy-2-(hydroxymethyl)propyl]nucleobases.

Acyclic, achiral nucleoside derivatives 1b-e of adenine, cytosine, 5-methylcytosine, and guanine, containing a 3-hydroxy-2-(hydroxymethyl)prop-1-enyl group on N-1 or N-9, have been prepared analogously to the previously described thymine derivative 1a. In contrast to the adenine and guanine derivatives, the cytosine derivative 9 was unstable, and was obtained in a low yield due to side reactions. These include cleavage of the propenyl group from the base, and the formation of a bicyclic compound. The thymine derivative, although stable under neutral conditions, likewise underwent a reversible cyclization reaction (Michael addition) in the presence of acids or bases. The 5-methylcytosine derivative was stable under neutral and basic conditions. Four other nucleoside derivatives 26a-d containing a 2,3-dihydroxy-2-(hydroxymethyl)propyl group on N-1 or N-9, three of which are new, have likewise been prepared. All compounds were evaluated as antiviral agents against HIV-1 and HSV-1 but were devoid of antiviral activity.

New monascus metabolites with a pyridine structure in red fermented rice.

Monascus purpureus produces several hitherto unknown compounds in addition to pigments and the mycotoxin citrinin. In red fermented rice (angkak, red koji) obtained as cultures of M. purpureus DSM1379 and DSM1603, we detected two compounds with identical UV absorption spectra and maxima at 306-307 nm. They were isolated by HPLC, and their structures were elucidated by intensive MS and NMR studies. Monascopyridine A (3) contains a gamma-lactone, propenyl group, hexanoyl side chain, and a pyridine ring, whereas the more lipophilic compound, monascopyridine B, is a higher homologue of monascopyridine A with the more lipophilic octanoyl instead of the hexanoyl side chain. This is the first report of Monascus metabolites with a pyridine ring.

High‐performance bismaleimide matrices: cure kinetics and mechanism

AbstractKinetics and mechanism of equifunctional 4,4′‐(N,N′‐bismaleimide)‐diphenylmethane/2,2′‐diallyl‐bisphenol A (BMDM/DABPA) and model (phenylmaleimide/2,2′‐diallylphenol) (PMI/AP) systems have been studied in the temperature range 140–400 °C using IR‐, 1H‐ and ­13C‐NMR spectroscopy, gas chromatography–mass spectrometry GCMS), differential scanning calorimetry (DSC) and isothermal calorimetry. It was established that the cure mechanism consists a unique combination of step‐wise and chain polymerization and polycondensation reactions: step‐wise “ene” addition reaction of allyl group to maleimide one and consecutive/parallel chain polymerization of maleimide and propenyl groups generated by first reaction. The latter reaction is the main crosslinking reaction. The second source of crosslinking is a dehydration reaction of phenol groups that proceeds with mandatory participation as one of the component 1:1 adduct (product of step‐wise polymerization). Homopolymerization of maleimide groups proceeds autocatalytically under the action of free radicals generated by thermal decomposition of maleimide‐propenyl groups' donor–acceptor pairs. Steric hindrance in 2,2′‐diallyl‐bisphenol A prevents the reversible Diels–Alder reaction but this reaction proceeds in model systems. Some thermodynamic and kinetic parameters of the reactions are determined. Copyright © 2003 John Wiley & Sons, Ltd.

New monascus metabolite isolated from red yeast rice (angkak, red koji).

Red yeast rice (angkak, red koji) obtained as cultures of Monascus purpureus on rice was extracted and analyzed by HPLC. In addition to the known red, orange, and yellow pigments and the mycotoxin citrinin, a new Monascus metabolite was detected. It is present in the original red yeast rice and formed in higher amounts when red yeast rice is heated. High-resolution mass spectrometry indicated the molecular formula C(15)H(12)O(4). The chemical structure was elucidated by analysis of NMR data. The new compound, named monascodilone, is characterized by a propenyl group on a pyrone ring, an aromatic ring, and a gamma-lactone group.

Synthesis and characterization of novel aromatic ether nitrile monomer containing propenylphenoxy groups and properties of its copolymer with 4,4′‐bismaleimidodiphenylmethane

A novel aromatic ether nitrile monomer containing propenyl groups, 2,6-di{2-[(E)-1-propenyl]phenoxy} benzonitrile (DPPB), was synthesized by the reaction of 2,6-dichlorobenzonitrile and 2-allylphenol using anhydrous potassium carbonate as the acid acceptor, N-methyl pyrrolidone as the dipolar aprotic solvent, and toluene as the dehydrating agent. The chemical structure of DPPB was characterized by FTIR and 1H-NMR. The monomer was used to modify a popular commercial bismaleimide, 4,4-bismaleimidodiphenylmethane (BMDPM), to improve the shear strength of the resin. The results showed that DPPB could effectively improve the shear strength of the BMDPM resin without decreasing the heat resistance of BMDPM. A better result was obtained when the composition of DPPB in the copolymer was 45 wt %. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1465–1472, 2002

Intramolecular Hydroalkylation as a Route to Strained Dicationic Bis(arene) [3]Ruthenocyclophanes

Base-promoted intramolecular hydroalkylation of the carbon−carbon triple bond in the ruthenium bis(arene) complexes [(p-cymene)Ru(η6-C6H5C⋮CR)][OTf]2 (1, R = Et; 2, R = Ph; OTf = O3SCF3) generates the strained [3]ruthenocyclophane complexes 3 and 4, in which a propenyl (−CH2CRCH−) group bridges the two arene ligands. The presence of the propenyl bridge results in a bent-metallocene structure for the [3]ruthenocyclophane cation in 4, with an angle of 11.8° between the arene ligands.

Synthesis and characterization of novel aromatic ether nitrile monomer containing propenylphenoxy groups and properties of its copolymer with 4,4′‐bismaleimidodiphenylmethane

AbstractA novel aromatic ether nitrile monomer containing propenyl groups, 2,6‐di{2‐[(E)‐1‐propenyl]phenoxy} benzonitrile (DPPB), was synthesized by the reaction of 2,6‐dichlorobenzonitrile and 2‐allylphenol using anhydrous potassium carbonate as the acid acceptor, N‐methyl pyrrolidone as the dipolar aprotic solvent, and toluene as the dehydrating agent. The chemical structure of DPPB was characterized by FTIR and 1H‐NMR. The monomer was used to modify a popular commercial bismaleimide, 4,4‐bismaleimidodiphenylmethane (BMDPM), to improve the shear strength of the resin. The results showed that DPPB could effectively improve the shear strength of the BMDPM resin without decreasing the heat resistance of BMDPM. A better result was obtained when the composition of DPPB in the copolymer was 45 wt %. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1465–1472, 2002

Syntheses and crystal structures of Cu(II) and Zn(II) complexes of 2,2′-dipyridyl( N-propenyl)amine

Reaction between copper(II)- and zinc(II)-nitrates and 2,2′-dipyridyl( N-propenyl)amine (Prdpa) affords 1:1 complexes M(Prdpa)(NO 3) 2 (M=Cu, 1; M=Zn, 5) for both metal ions and a 1:2 adduct M(Prdpa) 2(NO 3) 2 ( 2) for copper only. In ethanol 1 dissociates to form 2 and copper nitrate. X-ray diffraction studies on 1, 2 and 5, and on the 2,2′-dipyridylamine (Hdpa) analogue of 1, Cu(Hdpa)(NO 3) 2 ( 4), are reported. The metal centres exhibit square pyramidal ( 1) or distorted octahedral ( 2, 4, 5) primary coordination spheres. Bridging nitrate groups linking Cu atoms in 1 and 4 result in CuONOCu chains, which in the case of 4 are extensively cross-linked by N−H⋯ONO 2 H-bonding into 3D-arrays. Intermolecular C−H⋯ONO 2 interactions are apparent in the solid-state structure of 2. The structural effects of replacing the NH atom on Hdpa by a propenyl group in 6-coordinate Cu(II) complexes are assessed.

The polyaddition, chain, and polycondensation machanisms of formation of networks based on bismaleimides

The kinetics and mechanisms of polymerization of equifunctional 4,4'-(N,N'-bismaleimide)-diphenylmethane/2,2'-diallyl-bisphenol A (BMDM/DABPA) and model (phenylmaleimide/2-allylphenol) (PMI/AP) systems have been studied in the temperature range 140 – 400 °C using IR-, 1H and 13C NMR spectroscopy, GC/MS, DSC, and isothermal calorimetry. It was established that the cure mechanism consisted of a unique combination of step-wise and chain polymerization of maleimide and propenyl groups generated by the first reaction. The last reaction was the main branching reaction. The second source of branching was the dehydration reaction of phenol groups (polycondensation reaction) that proceeds with the participation of the 1:1 “ene” adduct as one of the component. Homopolymerization of maleimide groups proceeded autocatalytically, initiated by free radicals generated by thermal decomposition of the maleimide-propenyl group's donor–acceptor pairs. The steric hindrance in 2,2'-diallyl-bisphenol A prevented the reversible Diels–Alder reaction, but the reaction proceeded in model systems. Some thermodynamic and kinetics parameters of the reactions have been determined.

Synthesis and characterization of functionalized thermoplastics as reactive modifiers for bismaleimide resins

The preparation and characterization of a series of chemically functionalized oligosulphones (of approximate M n 5000–17 000 g mol−1) bearing propenyl groups substituted into the main aromatic backbone is reported. The thermal characterization of the oligomers using differential scanning calorimetry was carried out and the main features of the thermally-initiated process are presented. Blends of the oligomers were formed with a commercial bismaleimide and their thermal characteristics are also discussed. © 2001 Society of Chemical Industry

Additional cytotoxic neolignans from Persea obovatifolia

Four additional neolignans, comprising obovatifol [(2 S,3 S)-2,3-dihydro-2-(3,4-dihydroxy-5-methoxyphenyl)-7-methoxy-3-methyl-5- trans-propenyl benzofuran], obovaten [2-(3,4-dihydroxy-5-methoxyphenyl)-7-methoxy-3-methyl-5- trans-propenyl benzofuran], perseal C [(2 S,3 R)-2,3-dihydro-2-(3,4-methylenedioxyphenyl)-5-formyl-3-hydroxymethy-7- methoxy benzofuran] and perseal D [2-(3,4-dihydroxy-5-methoxyphenyl)-5-formyl-7-methoxy-3-methyl benzofuran] were isolated in a continuing study of the leaves of Persea obovatifolia. Obovatifol had been reported previously in a mass spectrometric analysis without any other spectroscopic data. Obovaten and perseals C and D are new compounds, bearing a C-1′ formyl side-chain, instead of a propenyl group. Their structures were elucidated from spectroscopic data; they showed significant cytotoxic activities against P-388, KB16, A549 and HT-29 cancer cell lines in vitro.

Zirconocene-(μ-Organyl)borate Betaines Derived by Treatment of a (σ-Alkenyl)(σ-alkynyl)zirconocene Complex with Tris(pentafluorophenyl)borane⋆

Hydrozirconation of propyne followed by treatment with propynyllithium yields the (σ-propenyl)(σ-propynyl)zir-conocene complex 11. Its treatment with the organometallic Lewis acid B(C6F5)3 results in transfer of the σ-propynyl group from zirconium to boron followed by insertion of the alkynylborate triple bond into the zirconium carbon bond of the remaining metallaallyl cation to furnish the zirconocene–(μ-hydrocarbyl)borate betaine complex 14. This reacts with three molar equivalents of tert-butyl isocyanide to give 16. Complex 16 contains a five-membered carbocyclic ring, formed by carbon-carbon coupling of the former propenyl and propynyl groups with the C≡N–R reagent, to which a (η2-iminoacyl)(ĸ-tert-butyl isocyanide)zirconocene moiety is attached. Complex 16 was characterized by an X-ray crystal structure analysis.

Electrochemical and spectroscopic studies on nickel(II/III) complexes with novel 14-membered hexaaza macrocycle functionalized with propenyl groups

A nickel(II) macrocyclic complex functionalized with propenyl groups, [Ni(1,8-di( n-propenyl)-1,3,6,8,10,13-hexaazacyclotetradecane)] 2+ {abbreviated as [Ni(A)] 2+}, has been synthesized by a simple template condensation reaction of the Ni 2+ ion, ethylenediamine, allylamine and formaldehyde in methanol. Spectral and electrochemical properties of the [Ni(A)] 2+ complex in various media have been investigated and compared with those of [Ni(1,8-dialkyl-1,3,6,8,10,13-hexaazacyclotetradecane)] 2+ complexes. The interaction of olefinic groups appended to the macrocycle with the nickel metal center is recognized by the spectral and electrochemical studies; in acetonitrile solution, the molar extinction coefficient of [Ni(A)] 2+ at λ max=458 nm grows up gradually and attains a maximum, and at the same time the cyclic voltammetric peak currents for the [Ni(A)] 2+/3+ redox couple decrease slowly with a concomitant growth of a new redox wave at more positive potentials. The first-order kinetic rate constants for the time dependent decrease of the peak currents of [Ni(A)] 2+/3+ redox couple are determined.

Synthesis of 3-Position-Modified Analogues of myo-Inositol 1,4,5-Trisphosphate, Tools for Investigation of the Polyphosphoinositide Pathway of Cellular Signaling.

Methods for the synthesis of 3-O-(carboxymethyl)- and 3-O-alkylated myo-inositol 1,4,5-trisphosphates in racemic form from myo-inositol have been devised. For DL-3-O-(carboxymethyl)-myo-inositol 1,4,5-trisphosphate, an analogue of myo-inositol 1,3,4,5-tetrakisphosphate, DL-3-O-allyl-2,6-di-O-benzyl-1-O-(p-methoxybenzyl)-4,5-O-isopropylidene-myo-inositol (14) was prepared from myo-inositol in seven steps. The triol DL-3-O-allyl-2,6-di-O-benzyl-myo-inositol (26), which was obtained after treatment of 14 with acid, was phosphitylated and the product oxidized to give the fully protected trisphosphate 27. The efficient oxidative cleavage of the 3-O-allyl ether of 27 in the presence of the cyanoethyl-protected phosphate triesters was achieved by treatment of 27 with NaIO(4)/RuCl(3).hydrate to afford the fully protected 3-O-(carboxymethyl) trisphosphate 28. After deblocking, DL-3-O-(carboxymethyl) trisphosphate 6 was obtained. For DL-3-O-alkylated myo-inositol 1,4,5-trisphosphate analogues, the fully protected 14 was isomerized to the cis-prop-1-enyl derivative 15. The propenyl group was removed to give DL-2,6-di-O-benzyl-1-O-(p-methoxybenzyl)-4,5-isopropylidene-myo-inositol (16). The 3-O-methyl ether 17, 3-O-ethyl ether 18, and 3-O-n-propyl ether 19 derivatives were synthesized by treatment of the anion of 16 with methyl iodide, ethyl iodide, or n-propyl iodide, respectively. Removal of the isopropylidene and p-methoxybenzyl groups afforded 3-O-alkylated triols 20, 21, or 22, which were phosphitylated and the products oxidized to give the respective fully protected 3-O-alkylated trisphosphates 23-25. Deprotection furnished 3-O-methyl- (3), 3-O-ethyl- (4), or 3-O-n-propyl-myo-inositol 1,4,5-trisphosphate (5). These compounds will be useful pharmacological tools to explore the interaction of myo-inositol 1,4,5-trisphosphate with its receptor and metabolic enzymes.

(E,Z)-2-(2-chloro-5-nitrostyryl)-1-(1-propenyl)benzimidazole.

The title compound, C18H14ClN3O2, was synthesized by the condensation of 2-chloro-5-nitrobenzaldehyde with 2-methyl-1-propenylbenzimidazole, and the molecule comprises a 2-chloro-5-nitrobenzene and a 1-(Z)-propenylbenzimidazole. The two aromatic moieties are conjugated through the vinyl group. The dihedral angle between the two rings is 1.4(6) degrees. The propenyl group lies out of the benzimidazole plane with a dihedral angle of 112.9(9) degrees.

Thermal Chemistry of Dihalopropanes on Ni(100) Single-Crystal Surfaces: Formation of Cyclopropane, Propene, and Propane

The thermal chemistry of 1,3-diiodopropane, 1-chloro-3-iodopropane, 1-iodopropane, 1-chloropropane, 3-chloropropene, propene, and cyclopropane on Ni(100) surfaces has been studied under ultrahigh vacuum conditions by using temperature-programmed desorption (TPD) and X-ray photoelectron spectroscopy (XPS). Cyclopropane, propene, propane, and hydrogen are all produced by thermal activation of the diiodopropane at low coverages, and iodopropane and molecular desorption are also seen at higher coverages. In contrast with this, only cyclopropane, propene, and chloropropanebut no propanewere observed after thermal activation of 1-chloro-3-iodopropane. Both I 3d and Cl 2p XPS spectra suggest that the adsorption of the dihaloalkanes is molecular below 100 K and that at low coverages both halogen atoms interact directly with the surface. They also point to the fact that the C−I (C−Cl) bonds break between 140 and 180 K in steps that most likely lead to the generation of a three-carbon metallacycle on the surface. These metallacycles may then undergo either intramolecular coupling to form cyclopropane or a dehydrogenation step to generate propenyl groups on the surface, and propenyl moieties, produced either by thermal activation of the metallacycle mentioned above or directly via the surface decomposition of 3-chloropropene, dehydrogenate to propene. Finally, some iodopropyl species are generated at high 1,3-diiodopropane coverages, and those incorporate a surface hydrogen to produce iodopropane (which either desorbs or undergoes a second C−I bond scission to give propyl species, the same as when starting directly with 1-iodopropane). 1-Chloro-3-iodopropane loses an iodine atom first, and some of the resulting 3-chloropropyl yields 1-chloropropane and 3-chloropropene, while the rest reacts further to produce cyclopropane and propene, as in the diiodopropane case. Nevertheless, very little cyclopropane is detected at high 1-chloro-3-iodopropane coverages or in the presence of coadsorbed hydrogen, presumably because the formation of metallacycle species is not favorable in that case. Finally, 1-chloropropane mostly desorbs molecularly and does not yield any hydrocarbon products.

New Trifluoromethyl Ketones as Potent Inhibitors of Esterases:19F NMR Spectroscopy of Transition State Analog Complexes and Structure–Activity Relationships

A variety of trifluoromethyl ketones (TFMKs) have been studied as inhibitors of the antennal esterases of the Egyptian armywormSpodoptera littoralis.The chemicals behaved as tight slow-binding inhibitors, the β-thio derivatives being the most potent ones, particularly 3-octylthio-1,1,1-trifluoropropan-2-one (OTFP) with an IC50of 0.08 μM. Other TFMKs, containing a propenyl group at the non-polar end of the molecule as in the natural pheromone structure (compounds4, 8and9), were also notably active. Correlation studies of inhibition with lipophilicity (log P) indicated that the optimum log P values for activity of the β-thio compounds are in the range of 3.03–5.11, while a higher lipophilicity (range 5.37-5.89) was required among the devoid of sulfur ketones.19F NMR studies, carried out with OTFP, showed that the inhibitor binds the enzyme in a reversible manner, forming an adduct (probably a hemiacetal) of tetrahedral geometry with the active site of the enzyme. To our knowledge, this is the first time that such a study on a natural esterase extract has been undertaken.

Synthesis of L-scyllo-inositol 1,2,4-trisphosphate, scyllo-inositol 1,2,4,5-tetrakisphosphate and phosphorothioate and DL-2-deoxy-2-fluoro-myo-inositol 1,4,5-trisphosphate: optical resolution of DL-1-O-allyl-3,6-di-O-benzyl-4,5-O-isopropylidene-scyllo-inositol

Routes for the synthesis of scyllo-inositol tris-and tetrakis-phosphates and 2-deoxy-2-fluoro-myo-inositol 1,4,5-trisphosphate from myo-inositol have been devised. For DL-scyllo-inositol 1,2,4-trisphosphate, DL-1-O-allyl 1–3,6-di-O-benzyl-4,5-O-isopropylidene-scyllo-inositol was prepared from the triflate of DL-1-O-allyl-3,6-di-O-benzyl-4–5-O-isopropylidene-myo-inositol by inversion at C-2. Removal of the isopropylidene group and phosphorylation gave the protected trisphosphate. Deblocking with sodium in liquid ammonia afforded racemic scyllo-inositol 1,2,4-trisphosphate. DL-1-O-Allyl-3,6-di-O-benzyl-4,5-O-isopropylidene-scyllo-inositol was resolved into its enantiomers by means of the crystalline 2-O-camphanate ester. The structure of one diastereoisomer, 1D-O-allyl-3,6-di-O-benzyl-2-O-[(–)-camphanate]-4,5–0-isopropylidene-scyllo-inositol was determined by single-crystal X-ray crystallography. 1D-(+)-1-O-Allyl-3,6-di-O-benzyl-4,5-O-isopropylidene-scyllo-inositol was used to prepare 1L(–)-scyllo-inositol 1,2,4-trisphosphate in a fashion analogous to the racemic modification. DL-1-O-Allyl-3,6-di-O-benzyl-scyllo-inositol was isomerised to the (Z)-prop-1-enyl derivative. The propenyl group was then removed to give the meso-1,4-di-O-benzyscyllo-inositol. Phosphitylation followed by oxidation or sulfoxidation gave the fully protected tetrakis-phosphate or -phosphorothioate, respectively. After deblocking and purification, scyllo-inositol 1,2,4,5-tetrakisphosphate and scyllo inositol 1,2,4,5-tetrakisphosphorothioate were obtained. DL-1-O-Allyl-3,6-di-O-benzyl-4,5-O-isopropylidene-scyllo-inositol was isomerised to the 1-O-[(Z)-prop-1-enyl] derivative which was converted into the 2-O-triflate. Displacement of the triflate using tetrabutylammonium fluoride proceeded with inversion of configuration to give DL-3,6-di-O-beflzyl-2-deoxy-2-fluoro-4,5-O-isopropylidene-1-O-([(Z)-prop-1-eny]-myo-inositol. Removal of propenyl and isopropylidene groups afforded DL-3,6-di-O-benzyl-2-deoxy-2-fluoro-myo-inositol, which was phosphitylated and the product oxidised to give the fully protected 2-fluoro trisphosphate. Deprotection furnished DL-2-deoxy-2-fluoro-myo-inositol 1,4,5-trisphosphate. These compounds will be useful probes for investigation of the polyphosphoinositide pathway of cellular signalling.

Volatile Components of Cooked Onions.

The headspace volatiles (HSV) of cooked onions and the odor concentrates of those which were prepared by simultaneous distillation and extraction (SDE) were analyzed by capillary gas chromatography (GC)and gas chromatography/mass spectrometry (GC-MS). As for the HSV analyses, a thermal desorption cold trapping method was used on injection to GC column. Both sliced and whole onion bulbs were used for sample preparation. Boiled, baked and microwave cooked onions were prepared. A total of 50 volatile compounds were identified from these cooked onions. The main component of cooked onion slices was dipropyl trisulfide which was scarcely found in cooked whole onion. Disulfides and trisulfides containing propenyl group were main components of the latter. Furans, including furfural, were the main compounds of baked onion which possessed a very sweet odor. The thermal degradation products of sugars Seemed to contribute to the sweet flavor of cooked onion.

Synthesis, characterization, and polymerization of propenyl ether analogues

AbstractA series of aromatic monomers bearing cationically polymerizable propenyl groups were prepared and characterized using the readily available starting materials: isoeugenol and o‐allyl phenol. Monomers with both propenyl and vinyl ether functional groups were also synthesized by the reaction of these starting materials with chloroethyl vinyl ether. The reactivity of the resulting monomers in photoinitiated cationic polymerization was studied using differential scanning photocalorimetry and photogel point measurements. Their thermal properties were determined using thermogravimetric analysis. © 1994 John Wiley & Sons, Inc.