bluuebunny/crossref_metadata_2025_split huggingface dataset:
Raman Study of Hydration Effect on Conformational Equilibria of Haloacetones
Authors: Shiratori Yosuke , Nanba Yoshiaki , Kato Minoru , Taniguchi Yoshihiro 
Published: March 2003

Abstract
The conformational equilibria of chloroacetone and bromoacetone in various solvents were investigated using temperature and pressure-tuning Raman spectroscopy. Three conformational equilibria of gauche←→trans, gauche←→trans′ (trans conformer whose halogen atom forms hydrogen bonds with water), and trans←→trans′ were observed in water. Thermodynamic quantities between the conformers of both haloacetones in various solvents were evaluated from the temperature and pressure dependence of the Raman intensities of the C–X (X: Cl and Br) stretching modes. The effects of the substitution of halogen atoms were observed in the enthalpy and volume differences between the conformers in water. From the present results together with the previous results for fluoroacetone, a good correlation between the conformational thermodynamics for haloacetones in water and the polarizabilities of the halogen atoms was shown.
Construction of a Picosecond Time-Resolved IR Dip Spectrometer for Studying Structures and Dynamics of Solvated Clusters
Authors: Sakai Makoto , Ueda Tadashi , Yamanaka Takaya , Fujii Masaaki 
Published: March 2003

Abstract
We have constructed a picosecond time-resolved IR dip spectrometer having a frequency resolution of &lt; 20 cm−1 and an instrument response time of 25 ps. In this system, the second harmonic of the idler wave from the OPA pumped at 800 nm and the remaining light from a regenerative amplifier (&lt; 2.5 mJ/pulse) were differentially mixed in a KTA crystal to generate tunable high-power IR light (2750–4000 cm−1; &gt; 60 μJ). The picosecond time-resolved IR dip spectra of phenol–(H2O)1 and carbazole–(H2O)1 are presented to demonstrate the capability of the constructed system. The spectral changes show clear vibrational structures of not only S0, but also S1 in the 2800–3800 cm−1 energy region. The system performance is also discussed.
Specific Complexation of Ursodeoxycholic Acid with Guest Compounds Induced by Co-grinding. II. Effect of Grinding Temperature on the Mechanochemical Complexation
Authors: Oguchi Toshio , Kazama Kazuo , Fukami Toshiro , Yonemochi Etsuo , Yamamoto Keiji 
Published: March 2003

Abstract
Ursodeoxycholic acid (UDCA) formed an inclusion complex with phenanthrene or with anthrone when being ground at an ambient temperature, while grinding at lower temperatures did not provide the complex but rather a mixture of amorphous UDCA and the guest compound crystals. Since heat treatment of the sample ground at low temperature did not provide the complex, it was concluded that the interplay of mechanochemical and thermal factors is responsible for the complexation of UDCA with the guest compound.
Schiff’s Bases Formed between Pyridoxal 5′-Phosphate and 4-Aminobutanoic Acid. Kinetic and Thermodynamic Study
Authors: Gorostidi Gerardo R Echevarría , Castellanos M Gabriela , Pérez Piedad Martín , Santos José G , Blanco Francisco García 
Published: March 2003

Abstract
The overall and individual kinetic constants of formation (k1 and k1i) and hydrolysis (k2, kOH and k2i) of the Schiff’s bases formed between pyridoxal 5′-phosphate (PLP) and 4-aminobutanoic acid (GABA) at 10, 20, 25, 30, and 37 °C, a variable pH and a constant ionic strength of 0.1 M (1 M = 1 mol dm−3) were determined. The formation of a Schiff’s base is an intramolecular acid-catalyzed process. The activation and thermodynamic parameters for the formation and hydrolysis of the Schiff’s bases were also determined. ΔH and ΔS for the individual processes were all found to be negative.
Molecular Modeling of the Solvent Structuring of DMSO around Cellulose Triacetate
Authors: Yu Isseki , Ueda Kazuyoshi , Nakayama Haruo 
Published: March 2003

Abstract
Molecular dynamics simulations of cellulose triacetate (CTA) were performed with explicit DMSO molecules in order to investigate the solvent structuring of DMSO around the CTA polymer. A hexamer unit of CTA was used as a model instead of polymer CTA. The molecular dynamics trajectory was started from a minimum conformation, which was found from an analysis of the adiabatic potential-energy surface obtained for glycosidic dihedral angles of φ and ψ. It showed that most of the time the trajectory stayed in their initial conformation in DMSO solvent. A distance analysis between the acetyl methyl residues of CTA showed that they are in good accordance with the NMR-NOESY data obtained by Tezuka.1 In order to elucidate the solvation structure of DMSO around the solute molecules, the site-specified radial distribution function, the orientation and the time courses of the DMSO movement were analyzed precisely. The results showed that some DMSO molecules strongly interact with CTA at specific sites, such as acetyl methyl residues and H1 ring protons. Moreover, it was found that those DMSO molecules frequently interact to CTA, not with one site, but with two or more sites simultaneously. These DMSO molecules would play an important role in the conformation of CTA in this solvent.
Conformation Preferences of 1,2-Dichlorotetranitroethane
Authors: Lam Yulin , Ma Ngai Ling , Huang Hsing Hua , Wang Li 
Published: March 2003

Abstract
The dipole moments of 1,2-dichlorotetranitroethane in carbon tetrachloride and benzene show that the compound favors the gauche conformer in solution-state. Experimentally derived values of the energy difference between the gauche and trans conformers and their population quotient are compared with values estimated by ab initio calculations. The agreement between experiment and theory is found to be excellent.
Deswelling Kinetics of a Porous Poly(N-isopropylacrylamide/methacrylic acid) Gel Prepared by Freeze-Drying
Authors: Kato Norihiro , Sakai Yasuzo , Kanazawa Atsushi 
Published: March 2003

Abstract
A linear correlation between the enthalpy of activation (ΔH≠) and the entropy of activation (ΔS≠) was observed for the deswelling process of porous poly(N-isopropylacrylamide/methacrylic acid) gels. The free energy of activation (ΔG≠) was nearly constant at +84 ± 2 kJ mol−1 irrespective of the methacrylic acid content and pH of the solutions.
Preconcentration of Trace Uranium from Natural Water with Solid-Phase Extraction
Authors: Shemirani Farzaneh , Abkenar Shiva Dehghan , Jamali Mohammad Reza 
Published: March 2003

Abstract
In the present study, an effective method was used for the preconcentration and determination of uranium(VI) by solid-phase extraction (SPE). For this purpose, a microcolumn of alumina modified with sodium dodecyl sulfate (SDS) and 1-(2-pyridylazo)-2-naphthol (PAN) was prepared for the preconcentration of trace uranyl(VI) from water samples. The uranium(VI) was completely eluted with 6.0 mol dm−3 HCl and determined by a spectrophotometric method with Arsenazo III. The SPE conditions were optimized by evaluating the effective factors such as pH, flow rate and masking agent. By the proposed method a preconcentration factor more than 150 was achieved. The average recovery of uranium(VI) was 99.8%. The relative standard deviation was 2.6% for ten replicate determinations of uranyl(VI) ion in a solution with a concentration of 50 ng cm−3. Some concomitant ions such as Cd2+, Ni2+, MoO42−, Cu2+, Th4+ and Ce3+, which interfere in the determination process of uranium(VI), were masked with EDTA in the aqueous phase during the extraction process. The proposed method was successfully used for the determination of uranium in natural water.
Syntheses and Structures of Mono- and Dinuclear Platinum Complexes of Pyrimidine-2-thiolate and Its 4-Methyl and 4,6-Dimethyl Derivatives
Authors: Asada Osamu , Umakoshi Keisuke , Tsuge Kiyoshi , Yabuuchi Shingo , Sasaki Yoichi , Onishi Masayoshi 
Published: March 2003

Abstract
The reaction of K2[PtCl4] with pyrimidine-2-thiol (pymSH) was reinvestigated. Among the possible four isomers, the major product was the cis isomer of [PtIII2Cl2(pymS)4] (1). The Pt(II) complex cis-[Pt2(pymS)4] (2) was prepared by the addition of NaOCH3 in the reaction mixture. The substitution of the axial Cl− ligands of 1 with Br− afforded the bromo complex [Pt2Br2(pymS)4] (3). While the reactions of K2[PtCl4] with 4-methylpyrimidine-2-thiol hydrochloride (4-mpymSH·HCl) in the presence of NaHCO3 gave a mixture of [Pt2Cl2(4-mpymS)4] (4) and trans-[Pt(4-mpymS)2] (5), the reaction with 4,6-dimethylpyrimidine-2-thiol (4,6-dmpymSH) gave only trans-[Pt(4,6-dmpymS)2] (7). The preference of bis-chelate mononuclear complexes for these ligands may be explained by considering steric hindrance between the ligands in the dimer. The oxidation of 5 by Ce(IV) afforded trans-dichloro Pt(IV) complex, [PtCl2(4-mpymS)2] (6). The crystal structures of 1, 3, 6 and 7 were determined. The redox properties of 1 and 3 are also discussed.
Hydrothermal Synthesis and Calorimetric Study of Blue Molybdenum Bronze, K0.28MoO3
Authors: Chin Kin , Eda Kazuo , Suzuki Takashi , Sotani Noriyuki 
Published: March 2003

Abstract
The hydrothermal heating of H0.28MoO3 in a KCl solution at 431 K led to the formation of a single phase of K0.28MoO3. Hydrated molybdenum bronze was formed as a mid-product during conversion from hydrogen molybdenum bronze to blue bronze. The formation enthalpy of K0.28MoO3 was determined by solution calorimetry to be ΔfH° (K0.28MoO3, s) = −840.2 kJ mol−1 at 298.15 K. The enthalpies of the transformation reaction from hydrogen bronze to hydrated bronze and of the formation reaction of blue K0.28MoO3 from hydrated bronze were calculated to be +33 kJ mol−1 and −48 kJ mol−1 at 298.15 K, respectively. The calculated enthalpies of the reactions were concordant with the suggested reaction mechanism for a transformation from hydrogen molybdenum bronze to potassium bronze.
Stereoselective Photoinduced Electron-Transfer Reaction between Zinc Myoglobin and New Chiral Quinolinium Ions
Authors: Tsukahara Keiichi , Ueda Rie 
Published: March 2003

Abstract
New chiral quinolinium derivatives, 1-[(S)- or (R)-(1-phenylethyl)carbamoylmethyl]-6-methoxyquinolinium hexafluorophosphate ([PMQ]PF6, 2) and 1-[(S)- or (R)-(1-phenylethyl)carbamoylmethyl]quinolinium hexafluorophosphate ([PQ]PF6, 3), were synthesized and characterized. A cyclic voltammetry in MeCN shows an irreversible redox behavior at −0.88 V and −0.85 V vs SCE (saturated calomel electrode) for 2 and 3, respectively. Fluorescence from the quinolinium moiety of 2 and 3 was observed at 455 nm and 440 nm, respectively. The fluorescence lifetime of 2 was longer than that of 3: τf = 30 ns (2) and 20 ns (3) in MeCN and τf = 26 ns (2) and 16 ns (3) in H2O). The excited triplet state of zinc-substituted myoglobin (3(ZnMb)*) was quenched by chiral [PMQ]+ and [PQ]+ ions; thereafter, the back electron-transfer (ET) reaction from a quinoline radical (PMQ• or PQ•) to a zinc myoglobin radical cation was detected. The stereoselectivity was observed for both ET quenching and back ET reactions; the (S)-isomers preferentially quench 3(ZnMb)* (kq(S)/kq(R) = 1.3 and 1.4 at 25 °C for [PMQ]+ and [PQ]+, respectively); in contrast, the (R)-isomers react faster than the (S)-isomers in the back ET reaction (kb(R)/kb(S) = 1.3 and 1.4 for PMQ• and PQ•, respectively). From a comparison of the rate constants with those for the previously reported systems we suggest that both the quenching and back reactions are controlled by ET, but not by conformational gating.
Degradation of Polychlorobiphenyls with Potassium Carbonate in Supercritical Water
Authors: Akiyama Fuminori 
Published: March 2003

Abstract
The degradation processes of 2,2′,5,5′-tetrachlorobiphenyl (4Cl-B) and 2,2′,4,4′,5,5′-hexachlorobiphenyl (6Cl-B) with potassium carbonate in supercritical water at 500 °C were studied. Hydrocarbons containing methane as major component were formed in the yield of around 15%. The main reaction product is considered to be inorganic salts, which do not show any NMR spectra and are easily decomposed by dilute acid.
The Layer Structure in Smectic A Phases and the Phase Transition Behavior for Cyano- and Nitrofuran Compounds
Authors: Tasaka Takeyasu , Okamoto Hiroaki , Morita Yuki , Abe Koichi , Kasatani Kazuo , Takenaka Shunsuke 
Published: March 2003

Abstract
The layer structure and phasetransition behavior of smectic A phases for 4-(4-alkoxyphenoxycarbonyl)phenyl 5-X-furan-2-carboxylates (X = CN, NO2) were examined by a small-angle X-ray diffraction method. The higher homologs of both compounds exhibit two kinds of smectic A (Sm A) phases and experience the Sm A-Sm A transition. One Sm A phase exhibited at a higher temperature region having a layer spacing of 1.5–1.9 times the calculated molecular length; and the layer spacing gradually increases with decreasing temperature. The other Sm A phase exhibited at a lower temperature region having a layer spacing of twice the calculated molecular length; also, the layer spacing is almost independent of the temperature. The Sm A–Sm A transition behavior is discussed.
Behavior of Naphthoyloxyl and Methoxynaphthoyloxyl Radicals Generated from the Photocleavage of Dinaphthoyl Peroxides and 1-(Naphthoyloxy)-2-pyridones
Authors: Najiwara Toshihiro , Hashimoto Ji-ichiro , Segawa Katsunori , Sakuragi Hirochika 
Published: March 2003

Abstract
1-Naphthoyloxyl and 2-naphthoyloxyl radicals were generated from photocleavage of dinaphthoyl peroxides and 1-(naphthoyloxy)-2-pyridones in acetonitrile. The difference in product distribution between the precursors is ascribed to the contribution of the two-bond cleavage in the peroxide decomposition in the singlet state. A series of methoxynaphthoyloxyl radicals were also generated from the corresponding (methoxynaphthoyloxy)pyridones and their behavior was compared with that of unsubstituted naphthoyloxyl radicals. The introduction of a methoxy group in the naphthalene ring stabilizes the naphthoyloxyl radicals to prevent their decarboxylation completely and reduces remarkably their reactivities in the addition to olefins and hydrogen-atom abstraction. The structure of the naphthoyloxyl radicals was discussed on the basis of their absorption spectra and MO calculations.
Difference between Enzymatic and Chemical N-methylations of Protoberberine-Type Alkaloid, Dependent on the Stereoisomer of (−)-N-methyl-7,8,13,13a-tetrahydroberberinium Salt
Authors: Kamigauchi Miyoko , Yoshida Mayumi , Noda Yuko , Nishijo Jujiro , In Yasuko , Tomoo Koji , Ohishi Hirofumi , Ishida Toshimasa 
Published: March 2003

Abstract
A possible relation between the stereostructure of (−)-(13aS)-tetrahydroberberine (1) and its enzymatic/chemical N-methylation, an important biosynthetic reaction to isoquinoline alkaloids in plants, was examined by CD spectroscopic, X-ray crystallographic, and energy calculation methods. The CD measurements indicated that 1 has two conformers (cis and trans) concerning the ring junction of the quinolizidine skeleton, and exist with a cis/trans ratio of about 1/4 in a diethyl ether : 2-methylbutane : ethanol (5 : 5 : 2) mixture. The dimensional/conformational difference between these cis and trans conformers was clarified by the X-ray crystal-structure analyses of two stereoisomers of N-methylated 1 (3 and 4). By using these structural parameters, the progress of N-methylation was simulated by energy profile calculations, suggesting that the cis and trans conformers are the major substrate for the enzymatic and chemical N-methylation reactions, respectively. Taking these results and the simulation of N-methylation of 1 by S-adenosyl-l-methionine at the binding pocket of N-methyltransferase into consideration, different pathways for chemical and enzymatic N-methylations of 1 have been proposed.
Multimetallic Complex Composed of Redox-Active Bridging Quinonediimine Ligand
Authors: Moriuchi Toshiyuki , Shen Xiuliang , Saito Kaori , Bandoh Seiji , Hirao Toshikazu 
Published: March 2003

Abstract
A π-conjugated quinonediimine ligand possessing two terminal redox-active ferrocenyl groups, N,N′-bis{(4′-ferrocenylcarboxamide)phenyl}-1,4-benzoquinonediimine (Lox), was synthesized. The quinonediimine ligand Lox was reduced to Lred composed of the phenylenediamine moiety on treatment with hydrazine hydrate. The reaction of Lox with the palladium(II) complex 1 bearing the N,N′-bis(2-phenylethyl)-2,6-pyridinedicarboxamide ligand afforded the multimetallic complex 2. Variable temperature 1H NMR studies of 2 indicated the existence of syn and anti isomers, in which the anti isomer is enthalpically more favorable than the syn isomer in CD2Cl2 by 0.9 kcal mol−1, but entropically less favorable by 2.6 cal mol−1 K−1 from the van’t Hoff plot. The redox function of the quinonediimine moiety is modulated by complexation with 1. The complex 2 showed three separate redox waves, which are assignable to the successive one-electron reduction of the quinonediimine moiety and oxidation of the two terminal ferrocenyl groups. Chemical reduction of 2 in CH2Cl2 with [Co(Cp)2] resulted in the appearance of ESR signals with weak 105Pd coupling centered around g = 2.004. The unpaired electron appears to locate mostly on the quinonediimine moiety with some delocalization onto the palladium center.
Micelle-Enhancing Effect on a Flavin-Photosensitized Reaction of Benzyl Alcohols in Aqueous Solution
Authors: Yasuda Masahide , Nakai Takuya , Kawahito Yasumasa , Shiragami Tsutomu 
Published: March 2003

Abstract
The tetra-O-acetylriboflavin (Fl)-photosensitized dehydrogenation of benzyl alcohols 1 proceeded more efficiently in aqueous solutions in the presence of sodium dodecyl sulfate (H2O/SDS) than acetonitrile solutions. The fluorescence quenching of Fl with 1 occurred efficiently in H2O/SDS. The apparent rate constants (kQ) for the fluorescence quenching were determined by Stern–Volmer plots. The plots of kQ vs the free-energy changes for the electron transfer from 1 to the excited singlet of Fl showed the Rehm–Weller-type correlation. However, plots for H2O/SDS were deviated from a curve calculated by the Rehm–Weller equation, although plots for MeCN were fitted to the calculated curve. The deviation in H2O/SDS is attributable to the incorporation of Fl and 1 into the hydrophobic domain of the SDS micelle, where the condensation, less-polar medium, and exteior negative charge operate favorably for efficient electron transfer.
Survey of Enhanced, Thermally Stable, and Soluble Second-Order Nonlinear Optical Azo Chromophores
Authors: Matsui Masaki , Suzuki Masayuki , Hayashi Masahiro , Funabiki Kazumasa , Ishigure Yoshinao , Doke Yasuo , Shiozaki Hisayoshi 
Published: March 2003

Abstract
A series of mono- and bisazo dyes were synthesized to obtain soluble, thermally stable, and enhanced second-order nonlinear optical chromophores (NLOphores). To prepare good sol-gel films, the most important factor was the solubility of NLOphores. Those azo NLOphores showing sufficient solubility were further classified into three groups: non-nitro-containing, nitro-containing, and fluorine-containing derivatives. Though non-nitro-containing NLOphores showed high solubility, their second-order nonlinearity was low. Nitro-containing NLOphores showed a rather high Td and a medium nonlinearity. Fluorine-containing NLOphores, especially perfluoroalkylsulfonyl derivatives, showed high nonlinearity and a rather low Td.
Synthesis and Properties of Monocyclic 5H-1,2-Oxathioles (Cyclic α,β-Unsaturated Sulfenic Acid Esters)
Authors: Ono Yutaka , Sugihara Yoshiaki , Ishii Akihiko , Nakayama Juzo 
Published: March 2003

Abstract
2,5,5-Trimethyl-3-hexyn-2-ol was successively treated with NaH and SCl2 in Et2O to provide 3-t-butyl-4-chloro-5,5-dimethyl-5H-1,2-oxathiole (1b), a class of α,β-unsaturated sulfenic acid ester, in 74% yield. Several S-unoxidized 5H-1,2-oxathioles were synthesized in similar ways. Analysis by cyclic voltammetry uncovered that the oxidation potentials of 1b, 3-(1-adamantyl)-4-chloro-5,5-dimethyl-5H-1,2-oxathiole (1c), and 4-chloro-5,5-dimethyl-3-phenyl-5H-1,2-oxathiole (1d) are +0.69, +0.68, and +0.78 V, respectively, and are lower than those of sulfides (thioanisole, +0.97 and dimethyl sulfide, +1.09 V), and also lower than that of an acyclic sulfenate ester (ethyl benzenesulfenate, +0.90 V). Thermolysis of 1c in boiling toluene furnished 2-(1-adamantyl)-3-chloro-4-methylthiophene in 81% yield.
Regio- and Stereo-Chemistry of Addition of Molecular Bromine to S-Oxidized Derivatives of 3,4-Di-t-butylthiophene: Exclusive 1,4-Cis-Additions
Authors: Nakayama Juzo , Furuya Tomohiro , Ishii Akihiko , Sakamoto Akira , Otani Takashi , Sugihara Yoshiaki 
Published: March 2003

Abstract
Bromine added to the 1-oxide, 1,1-dioxide, and sulfoximide derivatives of 3,4-di-t-butylthiophene exclusively in a 1,4-cis-addition mode. Thus, bromine added to 3,4-di-t-butylthiophene 1-oxide at room temperature in CH2Cl2 to give the 1,4-cis-adducts exclusively. The adducts are composed of two compounds in the ratio 57 : 43, where the major one is the anti-adduct respective to the S=O bond and the minor one is the syn-adduct. Addition of bromine to 3,4-di-t-butylthiophene 1,1-dioxide gave the 1,4-cis-adduct as the sole product. Addition of bromine to the N-tosyl substituted sulfoximide derivative of 3,4-di-t-butylthiophene afforded the single 1,4-cis-adduct in which two bromine atoms are anti to the N-tosyl group. Bromine added to the N-unsubstituted sulfoximide derivative of 3,4-di-t-butylthiophene to produce the 1,4-cis-addition products exclusively, which are a 67 : 33 mixture of the anti- and syn-adducts to the S=O bond.
Synthesis, Complexation Behaviors, and Crystal Structures of Azamacrocycles Having Tropon-2-yl Groups
Authors: Yamamoto Emi , Kubo Kanji , Mori Akira 
Published: March 2003

Abstract
Azamacrocycles 1–3, having one to three tropon-2-yl groups, were found to display unique absorption spectral changes in the presence of guest cations. Aza-15-crown-5 1, 1,7-diaza-12-crown-4 2a, 1,7-diaza-15-crown-5 2b, 1,10-diaza-18-crown-6 2c, and 1,5,9-triazacyclododecane 3 derivatives showed Ba2+, Zn2+, Ca2+, Ba2+, and Zn2+ selectivities, respectively. The crystal structures of free hosts 2a and 2c, the calcium thiocyanate complexes of 1 and 2c, the barium thiocyanate complex of 1, and the zinc thiocyanate complex of 2a were elucidated by X-ray analysis. The 2a·zinc and 2c·calcium thiocyanate complexes consist of an ion pair with a zinc tetrathiocyanate anion and a 2a·zinc cation and with a calcium hexathiocyanate anion and a 2c·H2O·calcium cation, respectively. The aminotropone moiety of 2a and 2c forms a conjugated 10-electron system. Complexation gave rise to deconjugation between the tropone ring and the nonbonding electron pair of the nitrogen atom to cause absorption spectral changes.
Deoxygenative Dimerization of Benzylic and Allylic Alcohols, and Their Ethers and Esters Using Lanthanum Metal and Chlorotrimethylsilane in the Presence of a Catalytic Amount of Iodine and Copper(I) Iodide
Authors: Nishino Toshiki , Nishiyama Yutaka , Sonoda Noboru 
Published: March 2003

Abstract
Benzylic and allylic alcohols were deoxygenatively dimerized by a treatment with lanthanum metal and chlorotrimethylsilane in the presence of a catalytic amount of iodine, giving the corresponding coupling products, alkanes, in moderate-to-good yields. This dimerization reaction was dramatically accelerated by the addition of a catalytic amount of copper(I) iodide. Similarly, ethers and esters were deoxygenatively dimerized by La/Me3SiCl/cat.I2/cat.CuI system in the presence of a catalytic amount of H2O.
Asymmetric Synthesis of the Main Pyridine Skeleton for a Macrobicyclic Antibiotic, Cyclothiazomycin
Authors: Endoh Nobuaki , Yonezawa Yasuchika , Shin Chung-gi 
Published: March 2003

Abstract
Stoichiometric asymmetric reduction of the ketone group of a 2-acetyl-3,6-disubstituted pyridine derivative with an oxazaborolidine and N-ethyl-N-isopropyl aniline-borane complex gave the corresponding (S)-lactone derivative 5 in 96% ee almost quantitatively. Hydrogenolytic cleavage of 5 gave the expected (S)-2-(1-hydroxyethyl)pyridine derivative.