Four new 2-(2-phenylethyl)chromone derivatives from withered wood of Aquilaria sinensis

Four new chromone derivatives, 5-hydroxy-6-methoxy-2-(2-phenylethyl)chromone (1), 6-hydroxy-2-(2-hydroxy-2-phenylethyl)chromone (2), 8-chloro-2-(2-phenylethyl)-5,6,7-trihydroxy-5,6,7,8-tetrahydrochromone (3), 6,7-dihydroxy-2-(2-phenylethyl)-5,6,7,8-tetrahydrochromone (4) were isolated from the MeOH extract of withered wood of Aquilaria sinensis, together with seven known constituents of agarwood.     

Enantioselective Resolution of (±)-l-Phenylethyl Acetate by Using the Whole Cells of Deep-sea Bacterium Bacillus sp. DL-2

Bacillus sp. DL-2 was isolated from the deep sea of the Western Pacific and further utilized as novel biocatalysts to efficiently asymmetrically hydrolyze (±)-1-phenylethyl acetate. After the optimization of hydrolytic reactions, chiral chemicals (R)1-phenylethanol and (S)-l-phenylethyl acetate were obtained with high optical purities (96% and 99.8%, respectively). Our research is about the asymmeric hydrolysis of (±)-1-phenylethyl acetate using whole-cell biocatalysts. In addition, the optical purity of (S)-l-phenylethyl acetate generated through the kinetic resolution of (±)-1-phenylethyl acetate using the whole-cells of Bacillus sp. DL-2 was the highest report so far. Using the whole cells of deep sea bacterium Bacillus sp. DL-2 as the biocatalysts is an enviromnentally friendly method and will play critical roles in industrial asymmetric synthesis.     

Six new 2-(2-phenylethyl)chromones from Agarwood

Six new chromones, 6-methoxy-2-[2-(3-methoxy-4-hydroxyphenyl)ethyllchromone (2), 6,8-dihydroxy-2-(2-phenylethyl)chromone (3), 6-hydroxy-2-[2-(4-hydroxyphenyl)ethyl]chromone (4), 6-hydroxy-2-[2-(2-hydroxyphenyl)ethyl]chromone (5), 7-hydroxy-2-(2-phenylethyl)chromone (6), and 6-hydroxy-7-methoxy-2-(2-phenylethyl)chromone (7) were isolated from the ether extract of agarwood in addition to a known compound, 2-(2-phenylethyl)chromone or flidersiachromone (1). Their structures were determined by spectroscopic methods including UV, IR, and NMR spectral data and comparisons with the calculated values using the hydroxyl and methoxyl substituent increments of the chromone ring.     

Reactions of N-(2,2-Dichloro-2-phenylethylidene)arenesulfonamides with Aromatic and Heterocyclic Compounds

Benzene, toluene, and 2-chlorothiophene regioselectively react with N-(2,2-dichloro-2-phenyl- ethylidene)arenesulfonamides in the presence of oleum to give N-[1-aryl(or hetaryl)-2,2-dichloro-2-phenylethyl]arenesulfonamides. Analogous C-amidoalkylation products are formed by the action of N-(2,2-dichloro- 1-hydroxy-2-phenylethyl)- and N-(1-arylsulfonylamino-2,2-dichloro-2-phenylethyl)arenesulfonamides on toluene and 2-chlorothiophene in concentrated sulfuric acid.     

A stable chiral diaminocyclopropenylidene

The chiral carbene bis[bis(R-1-phenylethyl)amino]cyclopropenylidene 2 and its dicarbene-silver complex [Ag(2)2]BF4 (3) have been isolated in good yields from the reactions of bis[bis(R-1-phenylethyl)amino]cyclopropenylium tetrafluoroborate (1)BF4 with potassium bis(trimethylsilyl)amide or with Ag2O, respectively; the molecular structures of (1)ClO4, 2 and 3 have been determined by X-ray diffraction analyses.     

Retention stereochemistry in ligand coupling reaction of optically active (1 R)-phenylethyl 2-quinolyl (R)- and (S)-sulfoxide with methylmagnesium bromide

Reactions of (+)-(1R)-phenylethyl 2-quinolyl (R)- sulfoxide 7a and (−)-(1R)-phenylethyl 2-quinolyl (S)- sulfoxide 7b with methylmagnesium bromide were examined. The reaction gave (R)-2-(1-phenylethyl)quinoline 9 as a ligand-coupling product, and a mixture of methyl(1R)-phenylethyl(R)-and (S)-sulfoxide 11a and 11b as ligand exchange products. The other (S) stereoisomer at the 1-phenylethyl carbon center was not detected in the reaction products. That is, both the ligand coupling and ligand exchange reactions proceeded with retention of configuration at the asymmetric carbon center.     

Studies on model oligosulfides to understand polysulfide polymers

1-bromo-1-phenylethane was reacted with aqueous sodium disulfide or sodium tetrasulfide to form the 1-phenylethyl polysulfides of sulfur rank 2 or 4 respectively. The distribution of the 1-phenylethyl polysulfides thus formed was studied using¹H NMR and GC-MS analysis. Apart from 1-phenylethyl disulfide and 1-phenylethyl tetrasulfide being produced in large amounts when aqueous sodium disulfide and sodium tetrasulfide were used respectively, the formation of 1-phenylethyl monosulfide in the former case and both mono and disulfide in the latter case, in minor amounts, is also observed. Also, it was found that the undetection of the molecular ion peaks of 1-phenylethyl polysulfides having rank above 2 is due to their thermal decomposition to elemental sulfur, 1-phenylethyl mono and disulfide, under the heating conditions employed for GC-MS analysis.     

Ligand coupling through σ-sulfurane — complete retention of configuration of 1-phenylethyl group in the reaction of 1-phenylethyl 2-pyridyl sulfoxide with grignard reagent1

The reaction of benzyl or 1-phenylethyl 2-pyridyl sulfoxide with Grignard reagent proceeds via a σ-sulfurane as an intermediate to give the coupling product, 2-benzylpyridine or 2-(1-phenylethyl)pyridine in quantitative yield. Stereochemistry for this reaction is complete retention at the benzylic carbon atom.     

Some reactions of 1-methyl-(2-phenylethyl)-1,2,3,4-tetrahydropyridines with organic azides. Synthesis of 1-methyl-(2-phenylethyl)piperidylidene-2-sulfonamides

The 1,3-dipolar cycloaddition reaction of 1-methyl- and 1-(2-phenylethyl)-1,2,3,4-tetrahydropyridines 7 with organic azides 8 afforded the respective 1-substituted-piperidylidene-2-sulfon(cyan)amides 9. Nitration of the 1-(2-phenylethyl) analogue 9o yielded the 1-[2-(4-nitrophenyl)ethyl] derivative 9r which on reduction with palladium-on-charcoal and hydrazine gave the 1-[2-(4-aminophenyl)ethyl] analogue 9s.     

Synthesis of four stereoisomers of protected 1,2-epiimino-3-hydroxypropylphosphonates

Enantiomerically pure protected 1,2-epiimino-3-hydroxypropylphosphonates were synthesised from hydroxy-1-{[(R)- or (S)-1-phenylethyl]aziridin-2-yl}methylphosphonates via regioselective ring opening with acetic acid followed by a stereospecific intramolecular cyclisation of 3-acetoxy-1-mesyloxy-2-(1-phenylethyl)aminopropylphosphonates and hydrogenolytic removal of the 1-phenylethyl group in the presence of Boc₂O. The trans-isomers of 3-acetoxy-[N-(1-phenylethyl)-1,2-epiimino]propylphosphonates exist as a 2:1 mixture of invertomers, which were fully structurally characterised based on their ¹H and ¹³C NMR spectroscopic data. Large differences in the ¹J_C-P values in N-(1-phenylethyl)aziridine-2-phosphonates were noticed depending on the spatial arrangement of the nitrogen lone pair and the phosphorus atom (syn-periplanar—ca. 215 Hz; anti-periplanar—182 Hz).     

Three 2-(2-phenylethyl) chromones and two terpenes from agarwood

A new Chromone, 7,8-dimethoxy-2-[2-(3'-acetoxyphenyl)ethyl]chromone (1) was isolated from an acetone extract of the Cambodian agarwood along with two known chromones, 6-methoxy-2-(2-phenylethyl)chromone (2) and 6,7-dimethoxy-2-(2-phenylethyl)chromone (3). In addition, an abietane ester (4) and the sesquiterpene dehydrofukinone (5) were isolated from the agarwood oil of the same origin. Structural elucidation of all isolated compounds was made based on IR, 1H and 13C NMR spectroscopic data.     

Preconcentration of gold,silver, palladium,platinum, and ruthenium with organophosphorus extractants

Extraction of noble metals in acid media with new tertiary phosphines and phosphine chalcogenides was examined. Tristyrylphosphine, tristyrylphosphine sulfide tris(2-phenylethyl)phosphine oxide, tris-(2-phenylethyl)phosphine sulfide, bis(2-phenylethyl)[2-(propylthio)ethyl]phosphine oxide, bis(2-phenylethyl)-[2-(butylthio)ethyl]phosphine oxide, and tris[2-(butylthio)ethyl]phosphine oxide were used as extractants. The suitability of the extractants for determination of Au, Ag, and Pd in rock and ore samples was elucidated.     

Reactions of zinc enolates derived from 1-aryl-2-bromo-2-phenylethanone and 2-bromoindan-1-one with alkyl 2-oxochromene-and 6-bromo-2-oxochromene-3-carboxylates

Zinc enolates derived from 1-aryl-2-bromo-2-phenylethanone react with alkyl 2-oxochromene-3-carboxylates and methyl 6-bromo-2-oxochromene-3-carboxylate to give, respectively, alkyl 4-(2-aryl-2-oxo-1-phenylethyl)-2-oxochroman-3-carboxylates and methyl 6-bromo-4-(2-aryl-2-oxo-1-phenylethyl)-2-oxochroman-3-carboxylate as a single stereoisomer. Zinc enolates derived from 2-bromoindan-1-one react with alkyl 2-oxochromene-3-carboxylates to give alkyl 2-oxo-4-(1-oxoindan-2-yl)chroman-3-carboxylates as a single stereoisomer.     

C3-chiral tripodal amido complexes

A comprehensive study into the coordination chemistry of two C3-chiral tripodal amido ligands has been carried out. The amido ligands contain a trisilylmethane backbone and chiral peripheral substituents. The amine precursors. HC(SiMe2NH[(S)-1-phenylethyl]]3 (1) and HC[SiMe2NH[(R)-1-indanyl]]3 (2) were found to be in equilibrium in solution with the cyclic diamines HC[SiMe2N[(S)-1-phenylethyl]2](SiMe2NH-[(S)-1-phenylethyl]] (3) and HC[SiMe2NH[(R)-1-indanyl]][SiMe2NH[(R)-1-indanyl]) (4), which are generated upon ejection of one molecule of the chiral primary amine. Reaction of these equilibrium mixtures with three molar equivalents of butyllithium instantaneously gave the trilithium triamides HC[SiMe2N(Li)[(S)-1-phenylethyl]]3 (5) and HC[SiMe2N(Li)[(R)-1-indanyl]]3 (6), both of which were characterised by an X-ray diffraction study. Both lithium compounds possess a central heteroadamantane core, in which the two-coordinate Li atoms are additionally weakly solvated by the three aryl groups of the chiral peripheral substituents, the Li-C contacts being in the range of 2.65-2.73 A. Reaction of 5 and 6 with [TiCl4(thf)2] and ZrCl4 gave the corresponding amido complexes [TiCl-[HC[SiMe2N[(S)-1-phenylethyl]]3]] (7), [TiCl(HC[SiMe2N[(R)-1-indanyl]]3]] (8), [ZrCl[HC[SiMe2N[(S)-1-phenylethyl]]3]] (9) and [ZrCl[HC[SiMe2N[(R)-1-indanyl]]3]] (10), respectively. Of these, compound 7 was structurally characterised by X-ray structure analysis and was shown to possess a C3-symmetrical arrangement of the tripod ligand. The chiral anionic dinuclear complex [Li-(OEt2)4][Zr2Cl3[HC[SiMe2N[(S)-1-phenylethyl]]3]2] (11) was isolated from reaction mixtures leading to 9. An X-ray diffraction study established its dimeric structure, in which the chiral amido ligands cap the two metal centres, which are linked through three symmetrically arranged, bridging chloro ligands. Reaction of 9 and 10 with a series of alkyl Grignard and alkyllithium reagents yielded the corresponding alkylzirconium complexes. X-ray structure analyses of [Zr(CH3)[HC[SiMe2N[(S)-1-phenylethyl]]3]] (12) and [Zr(CH3)-[HC[SiMe2N)[(R)-1-indanyl]]3]] (20) established their detailed molecular arrangements. While the reaction of 12 with the aryl ketones PhC(O)R (R = CH = CHPh, iPr, Et) gave the corresponding C-O insertion products, which contain an additional chiral centre in the alkoxy group, with low stereoselectivity (0-40% de). The corresponding conversions with several aryl aldehydes yielded the alkoxo complexes with high stereoselectivity. Upon hydrolysis, the chiral alcohols were isolated and shown to have enantiomeric excesses between 68 and 82%. High stereodiscrimination was also observed in the insertion reactions of several chiral ketones and aldehydes. However, this was shown to originate primarily from the chirality of the substrate. In analogous experiments with carbonyl compounds, the ethyl- and butyl-zirconium analogues of 12 did not undergo CO insertion into the metal-alkyl bond. Instead, beta-elimination and formal insertion into the metal-hydride bond occurred. It was found that the elimination of the alkene was induced by     

Well‐defined phosphonate‐functional copolymers through RAFT copolymerization of dimethyl‐p‐vinylbenzylphosphonate

Dibenzyltrithiocarbonate‐mediated RAFT polymerization of dimethyl‐p‐vinylbenzylphosphonate and its copolymerization with styrene are studied in order to access well‐defined statistical and block copolymers containing controlled amounts of dimethylphosphonate groups. NMR and SEC analysis of the (co)polymers confirm the controlled character of the polymerizations. ABA triblock copolymers are treated with TMSiBr/MeOH in order to transform the dimethylphosphonate groups into phosphonic acids while keeping the midchain trithiocarbonate group and triblock nature unaffected. Alternatively, the combination of trithiocarbonate aminolysis with TMSiBr/MeOH treatment of the same triblock copolymers leads to phosphonic acid‐functional diblock copolymer counterparts. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2616‐2624     

Reactions of <Emphasis Type="Italic">N</Emphasis>-(2,2,2-trichloroethylidene)- and <Emphasis Type="Italic">N</Emphasis>-(2,2-dichloro-2-phenylethylidene)arenesulfonamides with biuret

N-(2,2,2-Trichloroethylidene)- and N-(2,2-dichloro-2-phenylethylidene)arenesulfonamides react with an equimolar amount of biuret to give 1-(1-arylsulfonylamino-2,2,2-trichloroethyl)- or 1-(1-arylsulfonylamino-2,2-dichloro-2-phenylethyl)biurets. The reactions with 2 equiv of N-(polychloroethylidene)arenesulfonamides involve both amino groups in the biuret molecule, yielding the corresponding 1,5-bis(1-arylsulfonylamino-2,2,2-trichloroethyl)- and 1,5-bis(1-arylsulfonylamino-2,2-dichloro-2-phenylethyl)biurets.     

Synthesis and structure of bis(2-phenylethyl) phosphine selenide

Bis(2-phenylethyl)phosphine selenide was obtained with 86% yield from bis(2-phenylethyl)phosphine and selenium. XRD, IR, UV, and multinuclear NMR spectroscopic studies revealed that the phosphorus atom in the bis(2-phenylethyl)phosphine selenide molecule is four-coordinated irrespective of the phase state (crystals or solution).     

On the easy oxidation of (R)-2-[N-(1-phenylethyl)amino]-1-cyclopentenedithiocarboxylic acid to its disulfide dimer

The physical and spectroscopic data of (R)-2-[N-(1-phenylethyl)amino]-1-cyclopentenedithiocarboxylic acid are reviewed and the synthesis of (R)-di-[2-(N-(1-phenylethyl)amino]-1-cyclopentenedithiocarboxylic acid disulfide is described. The product resulting from the conjugate addition of the dithioacid to 2(5H)-furanone is also characterised.     

Cycloaddition of primary phosphines to divinyl sulfide

Primary phosphines reacted with divinyl sulfide under radical initiation conditions (AIBN, 65–70°C, reactant molar ratio 1:1) according to the addition-cyclization pattern to give 4-substituted 1,4-thiaphosphinanes which underwent almost quantitative oxidation with oxygen or elemental sulfur, yielding the corresponding 4-substituted 1,4-thiaphosphinane oxides (sulfides). The reaction of 4-(2-phenylethyl)-1,4-thiaphosphinane with methyl iodide afforded 4-methyl-4-(2-phenylethyl)-1,4-thiaphosphinanium iodide with high chemoselectivity.     

Separation and identification of positively charged and neutral nucleoside adducts by capillary electrochromatography-microelectrospray mass spectrometry

Capillary electrochromatography (CEC) is shown to be capable of separating mixtures containing both positively charged and neutral styrene oxide–adenosine adducts. In a study of the mechanism of deamination of positively charged 1-(2-hydroxy-1-phenylethyl) adenosine using ¹⁸O-labeled water, possible contamination of the chromatographically purified deamination product, 1-(2-hydroxy-1-phenylethyl) inosine, with the positively charged 1-(2-hydroxy-1-phenylethyl) adenosine was observed. Because the deamination product and the presumed contamination have the same molecular weights and similar structures, CEC-microelectrospray mass spectrometry (CEC-μESI/MS) was used to confirm the presence and identity of the suspected impurity. A trace amount of the positively charged 1-(2-hydroxy-1-phenylethyl) adenosine, which could not be observed by either HPLC-UV or CEC-UV, was detected by CEC-μESI/MS. This discriminatory ability of CEC-μESI/MS is attributed to the fact that positive ion mode ESI-MS is a more sensitive detector for a positively charged compound than a UV detector, and that the combination of electroosmotic and electrophoretic flows and hydrophobic interactions with the stationary phase contributes to the separation of the positively charged compound. As a result, the positively charged compound was observed to elute much earlier and with much sharper peaks than the neutral compounds for which electroosmotic flow is the only “pumping” force for the solvent.