bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dissolution Behavior of Optical Isomers of fac-Tris(aniono)cobalt(III) of Some α-Amino Acids in Water
Authors: Yoshimura Yasuki 
Published: July 2006

Abstract
fac-Tris(aniono)cobalt(III) of d-alanine, d-valine, d-leucine, l- and d-prolines, and l- and d-serines was synthesized, and the separation of the diastereoisomers of these chelates was attempted. The solubilities of these isomers in water were determined over the temperature range of 5 to 55 °C. The thermodynamic parameters of solution at 25 °C, such as the free energy (ΔGs°), enthalpy (ΔHs°), and entropy (ΔSs°), were estimated from the temperature dependence of the solubilities. Also, the dissolution behavior of these chelate in water was considered in terms of these thermodynamic parameters. Plot of ΔHs° against TΔSs° gave separate correlation lines for the groups comprising less soluble chelates and more soluble chelates. An increase in the solubility within the respective groups was caused by an increase in TΔSs°. Both ΔHs° and TΔSs° for the chelates of less hydrophobic glycine and serine were larger than those for the chelates of more hydrophobic amino acids.
Reaction of Vinylphosphonium Salts with Sulfoxonium Ylides. Synthesis of Cyclopropylphosphonium Salts
Authors: Okuma Kentaro , Ikari Komei , Ono Masaaki , Sato Yasunari , Kuge Seiji , Ohta Hiroshi , Machiguchi Takahisa 
Published: July 2006

Abstract
Reactions of (dimethylamino)phenylsulfoxonium methylide with triphenylvinylphosphonium salts gave the corresponding cyclopropyltriphenylphosphonium salts (E-form) in high yields, when 1,8-diazabicyclo[5.4.0]undec-7-ene was used as a base. Reactions of cyclopropyltriphenylphosphonium salts with sodium hydride in the presence of tris[2-(2-methoxyethoxy)ethyl]amine afforded the corresponding ylides, which further reacted with aldehydes to give alkylidenecyclopropanes in high yields.
Efficient Oxidation of Organic Compounds with Sodium and Silver Bromates NaBrO3, AgBrO3, in Non-Aqueous Solvents in the Presence of Lewis Acids
Authors: Firouzabadi Habib , Mohammadpoor-Baltork Iraj 
Published: July 2006

Abstract
The synthetic utility of sodium and silver bromates in the presence of Lewis acids as catalysts in organic solvents is described. They are efficient for the oxidation of alcohols, acyloins, and hydroquinones to their corresponding carbonyl compounds. The oxidation coupling of thiols performs well in the absence of the catalysts. Silver bromate is able to transform primary benzylic and saturated alcohols, aldehydes, and primary benzylic carbon–hydrogen bonds to their carboxylic acids efficiently. Secondary benzylic carbon–hydrogen bonds are oxidized to their carbonyl compounds with sodium and silver bromates.
Synthesis of Glucose-Containing Linear Oligosaccharides Having α(1→4) and α(1→6) Linkages Using Stereoselective Dehydrative Glycosylation
Authors: Koto Shinkiti , Haigoh Hisamitsu , Shichi Sonoko , Hirooka Motoko , Nakamura Teiko , Maru Chika , Fujita Misuzu , Goto Ayano , Sato Tomoko , Okada Masato , Zen Shonosuke , Yago Kazuo , Tomonaga Fumiya 
Published: July 2006

Abstract
Glycogen-storage-disease-relating linear tetra-, hexa-, and octasaccharides of d-glucose having α(1→4) and α(1→6) linkages were synthesized using a stereoselective dehydrative glycosylation with a reagent mixture of p-nitrobenzenesulfonyl chloride, silver trifluoromethanesulfonate, N,N-dimethylacetamide, and triethylamine. A cross-condensation of a quasi-stoichiometric amount of a donor and an acceptor of an octasaccharide, followed by deprotection, afforded a glucohexadecasaccharide.
Topochemical Photopolymerization of 4-[2-(Unsubstituted and Methyl-Substituted Pyrazinyl)ethenyl]cinnamates and -thiocinnamates in the Crystalline State
Authors: Saigo Kazuhiko , Sukegawa Makoto , Maekawa Yasunari , Hasegawa Masaki 
Published: July 2006

Abstract
Topochemical photopolymerization of 4-[2-(unsubstituted and methyl-substituted pyrazinyl)ethenyl]cinnamates and -thiocinnamates were carried out in the crystalline state. Upon photoirradiation, ethyl 4-[2-(unsubstituted and methyl-substituted pyrazinyl)ethenyl]cinnamates and S-ethyl 4-[2-(unsubstituted and methyl-substituted pyrazinyl)ethenyl]thiocinnamates gave α-hetero-type crystalline linear polymers, whereas methyl 4-[2-(methyl-substituted pyrazinyl)ethenyl]cinnamates afforded mixtures of β-type oligomers. The X-ray crystallographic analyses of the monomers revealed that the thioesters were more favorable monomers than the corresponding esters from the viewpoint of close packing in a crystal. The following factor(s) would play an important role in determining their molecular arrangements: 1) The close contact between the central 1,4-phenylene ring and the alkoxy oxygen of the ester group or the alkylthio sulfur of the thioester group, 2) the hydrogen bond between the interstacked pyrazinyl groups, and/or 3) the gearing of the alkyl group in the ester moiety with the methylpyrazinyl group.
Friedel–Crafts Acylation of Arenes Catalyzed by Bromopentacarbonylrhenium(I)
Authors: Kusama Hiroyuki , Narasaka Koichi 
Published: July 2006

Abstract
The intermolecular Friedel–Crafts acylation of aromatic compounds (such as toluene, m-xylene, and anisole) with various acid chlorides proceeds by using a catalytic amount of bromopentacarbonylrhenium(I) to afford aryl ketones. Intramolecular acylation is also catalyzed by the above-mentioned catalyst to give indanone and tetralone derivatives.
A Practical Synthesis of Mannosaminyl-β(1→4)-glucosyl-α(1→2)-rhamnose, the Trisaccharide Repeating Unit of a Streptococcus pneumoniae Capsular Polysaccharide
Authors: Kaji Eisuke , Lichtenthaler Frieder W , Osa Yumiko , Takahashi Keiko , Zen Shonosuke 
Published: July 2006

Abstract
An efficient chemical synthesis is described for the title trisaccharide repeating unit of the capsular polysaccharide of Streptococcus pneumoniae Type 19F. The key intermediate was a well-accessible indirect β-d-mannosaminyl donor, i.e. 2-(benzoyloxyimino)-2-deoxy-α-d-arabino-hexopyranosyl bromide, which underwent glycosidations with 20 : 1 β-selectivities; the benzoyloxyimino group was reduced with essential manno specificity. The ManNAc-β(1→4)-Glc disaccharide, thus obtained in suitably blocked form, was subsequently converted into 1-fluoride, with which a l-rhamnosyl acceptor was glycosylated by an α(1→2) linkage to yield the target trisaccharide in an altogether 6% overall yield for the 13 steps required from d-glucose.
Photodissociation and Vibrational Dynamics of OCS in the VUV Region
Authors: Yamanouchi Kaoru , Ohde Kyoko , Hishikawa Akiyoshi , Pibel Charles D 
Published: July 2006

Abstract
The photofragment excitation (PHOFEX) spectrum of jet-cooled OCS was remeasured for the 154.5 nm peak in the 1Σ+–1Σ+ transition by scanning a tunable vacuum ultraviolet (VUV) laser wavelength in the deep VUV region and by probing the S(1S) product with a second laser. Due to the efficient cooling of the sample in the free-jet expansion and the high-resolving power of the VUV laser, the homogeneous broadening of the dissociative state was derived directly from the observed PHOFEX spectrum. Based on the measured peak width, the lifetime (τ) of the dissociative state was determined to be τ 0.14 ps. The profile of the PHOFEX peak was found to be asymmetric and was fit to a Fano line profile to derive the value of the asymmetry parameter, q = −3.5(9), which indicates a considerable mixing of the continuum and discrete states in that particular energy region. A Fourier-transform analysis was also performed for the whole distinct absorption feature in the 160—140 nm region measured by McCarthy and Vaida [J. Phys. Chem., 92, 5875 (1988)], and the period of the vibrational motion on the dissociative potential-energy surface was derived to be 41 fs. Using these pieces of experimental evidence, the dissociation dynamics on the repulsive 1Σ+ surface in the 154.5 nm region was inferred.
A Zinc(II)–Cyclen Complex Attached to an Anthraquinone Moiety that Acts as a Redox-Active Nucleobase Receptor in Aqueous Solution
Authors: Tucker James H R , Shionoya Mitsuhiko , Koike Tohru , Kimura Eiichi 
Published: July 2006

Abstract
Recently, we demonstrated that a zinc(II) macrocyclic tetraamine complex, ZnII–cyclen (cyclen = 1,4,7,10-tetraazacyclododecane), could bind to thymidine (dT) and uridine (U) selectively among the DNA/RNA bases in aqueous solution at physiological pH. This paper describes the design and synthesis of the zinc(II) complex of an anthraquinone-pendant cyclen. The interaction of this complex with a variety of nucleosides has been studied by potentiometric pH titration, 1H NMR, and a polarographic technique. The effect of the anthraquinone functionality in this complex is an enhanced 1 : 1 association with N(3)-deprotonated dT (log K = 6.6 ± 0.1against 5.6 for ZnII–cyclen system at 25 °C with I = 0.10 (NaNO3)) and its congeners, implying an additional anthraquinone-thymine aromatic stacking π–π interaction. This complex, moreover, can electrochemically recognize thymidine and other related organic substrates in aqueous solution, and is therefore a new prototype for electrochemical oligonucleotide recognition.
Thermal Dissociation of Disilenes into Silylenes
Authors: Suzuki Hiroyuki , Tokitoh Norihiro , Okazaki Renji 
Published: July 2006

Abstract
Extremely hindered and stable disilenes (Tbt(Mes)Si=Si(Mes)Tbt {Tbt = 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl, Mes = 2,4,6-trimethylphenyl. (Z)-1: cis-isomer, (E)-1: trans-isomer}) underwent dissociation under very mild conditions (ca. 70 °C) into a divalent silicon species (Tbt(Mes)Si: (2)), which was trapped by methanol, triethylsilane, 2,3-dimethyl-1,3-butadiene, elemental sulfur, and elemental selenium to afford the corresponding adducts in good yields. Silylene 2 reacted with some carbon–carbon multiple-bond compounds to afford the corresponding [1 + 2] cycloadducts, among which the adduct with 3,3,6,6-tetramethylthiacyclohept-4-yne was established by an X-ray diffraction analysis. Silylene 2 also reacted with naphthalene and benzene to give the corresponding adducts, 15 and 17, respectively, the molecular structures of which were confirmed by X-ray crystallographic analyses. The formation of 15 and 17 represents the first example of [1 + 2] cycloaddition of silylenes to aromatic compounds. The thermolysis of 15 and 17 regenerated silylene 2, which was trapped with triethylsilane. A kinetic study of the thermal dissociation of 1 gave the activation parameters, which were compared with those for E Z isomerization of previously reported disilenes.
Photoelectrochemical Properties of RuS2-Coated TiO2 Electrodes
Authors: Ashokkumar Muthupandian , Kudo Akihiko , Sakata Tadayoshi 
Published: July 2006

Abstract
Photoelectrochemical studies of RuS2-coated TiO2 electrodes showed semiconductor sensitization by RuS2 fine particles on TiO2. RuS2 particles of ca. 100 nm size were observed from a scanning electron micrograph of the RuS2/TiO2 electrode surface. RuS2-coated TiO2 electrodes showed continuous wide absorption in the visible spectral region. Photoelectrochemical measurements of several RuS2/TiO2 electrodes, prepared under different conditions, were carried out. The electron-transfer efficiency from RuS2 to TiO2 was affected by the number of RuS2 colloid coatings and the preparation temperature of the RuS2 colloids. A schematic study was carried out on the effect of a heat treatment in order to find the optimum temperature for the maximum sensitization efficiency. A comparison of the absorption and action spectra of the RuS2/TiO2 electrode showed that only small RuS2 particles with a critical size distribution could transfer the photo-generated electrons to TiO2. A band-gap value of ca. 2.8 eV was evaluated (from the photocurrent action spectrum) for the RuS2 particles with high sensitization efficiency. A scheme which shows the energy diagram for RuS2 fine particles has been proposed by considering the flat-band potential values derived from the photocurrent onset potentials and the above-mentioned band-gap value.
Critical Demicellization Concentration of Diethylammonium Perfluorononanoate and Diethylammonium Tetradecyl Sulfate Mixture in Aqueous Solution
Authors: Asakawa Tsuyoshi , Shiraishi Tsugunori , Sunazaki Shinichi , Miyagishi Shigeyoshi 
Published: July 2006

Abstract
The micellar pseudophase diagram of diethylammonium perfluorononanoate (DEAPFN) and diethylammonium tetradecyl sulfate (DEATS) was determined by both conductivity and fluorescence probe methods. The conductivity measurements gave unusually low dissociation degrees of counter ion for DEAPFN-rich regions in contrast to those for DEATS-rich region. The micelles in a DEAPFN-rich region have high microviscosities, suggesting a micellar growth. The existence of the second cmc indicated the presence of two types of mixed micelles, but the mutual solubility of fluorocarbon and hydrocarbon surfactants in micellar pseudophase showed significant differences between DEAPFN–DEATS and LiPFN–LiTS systems. Third inflection points on both conductivity and fluorescence intensity curves were observed for DEAPFN–DEATS system. This suggests the presence of a critical demicellization concentration (CDC).
Molecular Dynamic Study of Conformational Properties of Cyclopenta[a]phenanthren-17-ones. Comparison of Theoretical Structures to X-Ray Structures
Authors: Kingsford-Adaboh Robert , Kashino Setsuo 
Published: July 2006

Abstract
The conformational analysis of a group of carcinogenic cyclopenta[a]phenanthren-17-ones has been done using quenched molecular dynamics to simulate built models. Optimum energy conformers have been searched within 300 to 600 K. The results are presented and compared to structures derived from X-ray experiments. While the pattern of distortion is similar for the simulated molecules to the crystalline state, the conformers corresponding to minimum energy show more molecular distortions in the free state than the crystalline at the bay regions. From the results, it emerges that the observed out-of-plane distortions are an inherent feature of the bay region substituted compounds.
Solid Solutions in Metal Complexes. Solubility Phase Diagrams and X-Ray Crystal Structures of trans(N,t-N)-[Co(norleucinato)(tren)]I2 and trans(N,t-N)-[Co(methioninato)(tren)]I2 [tren = tris(2-aminoethyl)amine]
Authors: Yamanari Kazuaki , Fuyuhiro Akira 
Published: July 2006

Abstract
Ternary solubility diagrams of trans(N,t-N)-[Co(n-leu)(tren)]I2 and trans(N,t-N)-[Co(met)(tren)]I2[t-N = tertiary amine nitrogen, n-leu = norleucinate(1-), met = methioninate(1-), and tren = tris(2-aminoethyl)amine] were determined at 25.0 °C. A single isotherm was found; the tie lines do not converge to any apexes of the enantiomers in either system. The solid phases are variable over the entire region from d : l(%) = 100 : 0 to 0 : 100, and both systems form a solid solution. The X-ray crystal structures of trans(N,t-N)-[Co(Dl-n-leu)(tren)]I2 (1; d : l = 50 : 50) and trans(N,t-N)-[Co(Dl-met)(tren)]I2 (3; d : l = 50 : 50) were determined from 3600 and 4699 reflections to R = 0.036 (Rw = 0.046) and R = 0.045 (Rw = 0.068), respectively: space group P21/c with a = 9.204(4), b = 11.057(2), c = 19.576(3) Å, β = 95.95(2)°, and Z = 4 for 1 and space group P21/n with a = 13.032(4), b = 11.210(4), c = 13.535(2) Å, β = 92.62(2)°, and Z = 4 for 3. The results confirm the co-existence of the d- and l-amino acidato complex ions in each site of the unit cell in both complexes. Furthermore, the unit cell comprises two d-rich sites and two l-rich sites: The unequal occupancy of the d- and l-amino acidato complex ions in each site is found irrespective of the racemic composition.
Preparations and 13C and 195Pt NMR Spectra of Platinum(II) Peptide Complexes and Their Growth-Inhibitory Activity against Mouse Meth A Solid Tumor in Vivo
Authors: Watabe Masatoshi , Takayama Toshio , Kuwahara Akira , Kawahashi Takako , Koike Yoshio , Horiuchi Akira , Suzuki Masuko , Watanabe Toshihiko , Mikami Ken , Matsumoto Tatuji , Narusawa Yoshio 
Published: July 2006

Abstract
Several dipeptide complexes of the form K[Pt(x-gly or gly-x)Cl], where x-gly or gly-x stands for a dipeptide anion (where x is glycine, alanine, valine, or leucine) moieties, were synthesized, purified, and characterized by various analytical and spectroscopic techniques (13C, 195Pt NMR and MS(FAB)). The complexes of the form K[Pt(x-gly)Cl] were pale brown and those of K[Pt(gly-x)Cl] were light yellow in solid form or in solution. The former was more labile than the latter in H2O solution. Growth inhibition assays of K[Pt(alagly)Cl], K[Pt(glyala)Cl], and cis-diamminedichloro platinum(II) (Cisplatin) against methylcholanthrene induced Meth A fibrosarcoma (Meth A) solid tumors transplanted in BALB/c mice were measured. In mice in the group administered K[Pt(glyala)Cl] doses of 26 mg kg−1 d−1, 28.9% of slight growth inhibition was observed. The side effects related to the decrease of body weight were mild. Cisplatin did not show any antitumor activity under the present administration conditions. The toxicities of the dipeptide complexes against normal mouse bone marrow cells were measured. All of them exhibited toxicity against bone marrow cells, but K[Pt(alagly)Cl] and K[Pt(glyala)Cl] were 1000 times less toxic than Cisplatin.
Syntheses, Characterization, and Properties of Vanadium(III) Complexes Containing Tripodal Tetradentate Ligands with Single Pyridyl Groups
Authors: Kanamori Kan , Kameda Eiji , Kabetani Takatsugu , Suemoto Taiko , Okamoto Ken-ichi , Kaizaki Sumio 
Published: July 2006

Abstract
The syntheses, characterization, and properties of [V(pda)(OH)(H2O)] (1a), [V2(μ-O)(pda)2(H2O)2] (1b), [V2(μ-O)(bpg)2Br2] (2), and [V2(μ-O)Br2(tpa)2]Br2 (3) are described, where pda (N-(2-pyridylmethyl)iminodiacetate), bpg (N,N-bis(2-pyridylmethyl)glycinate), and tpa (tris(2-pyridylmethyl)amine) are tripodal tetradentate ligands with single pyridyl groups. Complexes 1a, 1b, and 2 were characterized on the basis of their electronic and Raman spectra. The structure of 3 was determined by X-ray crystallography. Complex 3 crystallizes in the space group with the following unit cell dimensions: a = 11.505(5), b = 11.509(5), c = 16.348(7) Å, α = 103.73(2)°, β = 103.71(2)°, γ = 93.26(3)°, and Z = 2. The V–O–V angle is 175.3(2)° and the V–μ-O distances are 1.783(2) and 1.784(2) Å. In complex 3, the four unpaired electrons are ferromagnetically coupled. It was found that there is a positive correlation between 2 × νas(V–O–V) and the energy of the oxo-to-V(III) charge-transfer transition for single oxo-bridged dinuclear vanadium(III) complexes including the present complexes. This correlation is discussed in terms of the π character of the V(III)–μ-O bond that is affected by the remaining donor groups.
Modified Borohydride Agents, 1-Benzyl-4-aza-1-azoniabicyclo[2.2.2]octane Tetrahydroborate (BAAOTB) versus Tetrabutylammonium Tetrahydroborate (TBATB). Efficient, Selective, and Versatile Reducing Agents
Authors: Firouzabadi Habib , Afsharifar Gholam Reza 
Published: July 2006

Abstract
1-Benzyl-4-aza-1-azoniabicyclo[2.2.2]octane tetrahydroborate (BAAOTB) and tetrabutylammonium tetrahydroborate (TBATB) are used for the selective reductions of aldehydes, ketones, α,β-unsaturated carbonyl compounds, acid chlorides, azides, epoxides, and disulfides in t-BuOH and hexane/chloroform. ABBOAB with its rigid and bulky structure reacts more selectively than its analogue TBATB.
Solvent Effects on Anchimerically Assisted Solvolyses. II. Solvent Effects in Solvolyses of threo-2-Aryl-1-methylpropyl p-Toluenesulfonates
Authors: Fujio Mizue , Saeki Yoshihiro , Nakamoto Kenichiro , Yatsugi Ken-ichi , Goto Naomi , Kim Sung Hong , Tsuji Yutaka , Rappoport Zvi , Tsuno Yuho 
Published: July 2006

Abstract
The solvent effects on the solvolysis of threo-2-aryl-1-methylpropyl p-toluenesulfonates were analyzed with the aid of the extended Winstein–Grunwald Equation. The aryl-assisted kΔ solvolysis of 2-(p-methoxyphenyl)-1-methylpropyl and 2-methyl-2-phenylpropyl p-toluenesulfonates failed to give a single linear correlation with the YOTs parameter. The dispersion against YOTs cannot be due to nucleophilic solvent assistance. The m values from the plots of 2-(p-methoxyphenyl)-1-methylpropyl and 2-methyl-2-phenylpropyl p-toluenesulfonates against YOTs were significantly lower than m = 1.0 for the limiting kc solvolysis. Significantly improved correlations (R &gt; 0.99; SD &lt; 0.14) were obtained for the p-methoxy, 3-chloro-4-methoxy, and p-methyl derivatives with the YΔ scale based on the solvolysis of 2-(p-methoxyphenyl)-2-methylpropyl p-toluenesulfonate, instead of with YOTs. No improvement by the YΔ treatment was obtained for the unsubstituted compound (R = 0.97; SD = 0.22). A new similarity comparison analysis in terms of YOTs and YΔ, i.e., log (k/k80E) = mcYOTs + mΔYΔ, was applied successfully to the present kΔ solvolyses. The degree of YΔ character relative to the YOTs one, scaled by mΔ/(mc + mΔ), varies for 1-methyl-2-phenylpropyl tosylates in the range from 1.0 to 0.00 in the consistent manner expected if the dispersion in the YOTs plot becomes less pronounced for solvolyses of less significant anchimeric assistance. There is a continuous spectrum of behavior between the extreme pure kc mechanism and the extreme pure kΔ one.
Solvent Effects on the Solvolysis of Benzyl Tosylates. Behavior of Derivatives with Electron-Donating Substituents
Authors: Fujio Mizue , Susuki Toshihiro , Yatsugi Ken-ichi , Saeki Yoshihiro , Goto Mutsuo , Kim Sung Hong , Tsuji Yutaka , Rappoport Zvi , Tsuno Yuho 
Published: July 2006

Abstract
Solvolysis rates of p-methylbenzyl and 3-bromo-4-(methylthio)benzyl p-toluenesulfonates were measured in a wide variety of solvents and the solvent effects were compared with those for less activated benzyl tosylates and other related benzylic substrates. Plots of the dual parameter Winstein–Grunwald Equation failed to give satisfactory correlations using the ordinary 2-adamantyl YOTs parameter. m Values close to unity for both derivatives were obtained but the linearity of the correlations was unsatisfactory. Although the high response (m value) to the solvent polarity and the low l value may indicate a nearly limiting mechanism, the pattern of dispersion observed in binary solvent mixtures cannot be interpreted in terms of nucleophilic solvent assistance. The use of the polarity scale YΔ derived from 2-methyl-2-(p-methoxyphenyl)propyl tosylate solvolysis instead of YOTs significantly improved the correlations. The dispersion can be ascribed to the varying solvation-desolvation interactions characteristic of highly delocalized cationic centers in binary solvent mixtures. We used extended similarity comparison analysis, log (k/k80E) = mcYOTs + mΔYΔ + (lN). Based on the resulting characteristic susceptibility parameters, the mechanisms of benzyl solvolysis and the structures of relevant benzylic solvolyses transition states are discussed.
Synthesis of an Artificial HMG-CoA Reductase Inhibitor NK-104 via a Hydrosilylation–Cross-Coupling Reaction
Authors: Takahashi Kyoko , Minami Tatsuya , Ohara Yoshio , Hiyama Tamejiro 
Published: July 2006

Abstract
The hydrosilylation of t-butyl (3R,5S)-3,5-isopropylidenedioxy-6-heptynoate with ClMe2SiH and a platinum catalyst, t-Bu3P·Pt(CH2=CHSiMe2)2O, gave an (E)-vinylsilane in high yield with high regioselectivity. A subsequent cross-coupling reaction with an aryl halide afforded t-butyl (3R,5S,6E)-7-aryl-3,5-isopropylidenedioxy-6-heptenoate. This sequence was applied to the synthesis of a potent HMG-CoA reductase inhibitor, NK-104.