bluuebunny/crossref_metadata_2025_split huggingface dataset:
Peroxomonophosphoric Acid Oxidation. V. A Kinetic and Mechanistic Study of Oxidation of Aminobenzoic Acids in Acid Medium. Double Bell Shaped pH Rate Profile
Authors: Panigrahi Ganesh Prasad , Panda Abhina Kumar 
Published: July 2006

Abstract
Anthranilic acid and p-aminobenzoic acid were oxidized with peroxomonophosphoric acid in aqueous acid medium to the corresponding azoxy derivatives. Suitable rate laws for the double bell shaped pH rate profile were derived and rationalized on the basis of protonation of the amino group and ionization of the carboxyl group. The mechanism of oxidation involves the nucleophilic attack of nitrogen on the electrophilic peroxo oxygen. The reactivity of different peroxomonophosphoric acid species has been estimated.
Monophotonic Ionization Mechanism of N,N,N′,N′-Tetramethyl-1,6-pyrenediamine in Acetonitrile Solution
Authors: Nogami Takashi , Mizuhara Toshio , Kobayashi Naoki , Aoki Masaaki , Akashi Takao , Shirota Yasuhiko , Mikawa Hiroshi , Sumitani Minoru 
Published: July 2006

Abstract
Monophotonic ionization of N,N,N′,N′-tetramethyl-1,6-pyrenediamine (TMPDA) in acetonitrile was studied by means of ns laser photolysis and transient photocurrent measurement. The time dependences of the absorption of TMPDA cation radical and of the photocurrent were different. Photoionization thus occurs through an ionpair state.
The Separation of Solutes with Different Diffusion-coefficients by Two-layer Convection
Authors: Kamakura Katsuyoshi 
Published: July 2006

Abstract
When a two-layer system which consists of water (upper layer) and an aqueous solution (lower layer) is heated from one side and cooled from the opposite side, a convection starts in each layer. The empirical formula for mass transfer between the convections was studied for a system of water containing a mixture of solutes; the flux of a solute in the mixture was found to be proportional to the square root of the diffusion coefficient of the solute. Therefore, solutes with different diffusion-coefficients can be separated by two-layer convection.
1,3-Dioxolane Bearing Perfume and Herbicide Aldehyde Residues
Authors: Kamogawa Hiroyoshi , Haramoto Yuichiro , Nakazawa Terumi , Sugiura Harumitsu , Nanasawa Masato 
Published: July 2006

Abstract
4-Methacryloyloxymethyl-1,3-dioxolanes substituted at the 2 position with perfume and herbicide aldehyde residues were synthesized either by acetalization or by transacetalization involving 2,3-dihydroxypropyl methacrylate. The effect of the 2-substituent of the dioxolane ring on the rate of hydrolysis was remarkable.
Substituent Effect on the N–H Stretching Absorptions of 2-(Substituted anilino)pyridines
Authors: Hirota Minoru , Kobayashi Kunio 
Published: July 2006

Abstract
The N–H stretching frequencies of the title compounds were determined precisely. These amines have two absorption bands in the N–H stretching region owing to the existence of the rotational isomers. Their frequencies were plotted against the Hammett σ-constants of the substituents, giving a negative ρ-value. The results gave support to the planar (sp2) conformation of the exo-cyclic nitrogen atom.
A Selective Monodehydration of C4−14-α,ω-Alkanediols with Stearic and/or Palmitic Acids
Authors: Yamanaka Tohr , Imai Takashi 
Published: July 2006

Abstract
The formation of monoesters of the C4−14-α,ω-alkanediol(1) with stearic and/or palmitic acids and the consecutive pyrolysis of the monoesters to an ω-alken-1-ol(2) were effected at 320–350 °C under 260–760 mmHg** in a backmix flow reactor of a constant volume equipped with a fractionating column, through which the unchanged 1 was partially recycled. The selectivity in the preparations of 2(C6, C10, and C14) was greater than 79%.
Regiospecific Synthesis of 3-Alkylfurans and 3-Alkylthiophenes via Organoboranes
Authors: Akimoto Itaru , Sano Masahiro , Suzuki Akira 
Published: July 2006

Abstract
The reaction of bromine or iodine with ate-complexes obtained from trialkylboranes and 3-lithiofuran or 3-lithiothiophene gives the corresponding 3-alkylfurans or 3-alkylthiophenes in good yields, respectively.
The Equilibrium and the Vibrational Spectra of the t-Butylamine–Chloroform System
Authors: Kanesaka Isao , Izumi Mitsue , Mitsuishi Misaki , Kawai Kiyoyasu 
Published: July 2006

Abstract
The thermodynamic constants, ΔH° and ΔS°, of the t-butylamine (TBA)–chloroform-d system in carbon tetrachloride are obtained from the analysis of the Raman intensities observed in the C–D stretching region of chloroform-d, while the ΔH° on the associated species of TBA·CDCl3 and (TBA)2·CDCl3 are evaluated to be −14.2 and −22.6 kJ/mol respectively. The IR or Raman spectrum of a solid sample, adjusted by the rapid cooling of a gaseous or liquid one respectively, with the TBA: chloroform ratio of ≈1 is compared with that of TBA in the gaseous, liquid, or solid state; it is confirmed, on the basis of the assignments of the observed frequencies, that the solid sample consists almost entirely of the associated species of TBA·CHCl3. Only one associated species of (TBA)2·CHCl3 is also obtained by the crystallization of the gaseous sample with the molar ratio of 2.0. The NH2 group vibrations in TBA·CHCl3 or (TBA)2·CHCl3 are related intimately in their frequencies and band shapes to those in gaseous or solid TBA respectively.
The Thermal and Hydrothermal Behavior of Silica-adsorbed Magnesium Hydroxide
Authors: Muraishi Haruto 
Published: July 2006

Abstract
Silica-adsorbed Mg(OH)2 was treated thermally and hydrothermally. The resulting change in the adsorption layer was followed, and the effects of the adsorbed silica on the change in the bulk (Mg(OH)2, MgO) were examined. (1) Thermal treatment: The dehydration temperature of Mg(OH)2 increased with an increase in the amount of silica adsorbed, and it was higher by 25 °C for Mg(OH)2 adsorbing silica above 0.4 mmol/g than for pure Mg(OH)2. The amorphous silicate of the adsorption layer on the Mg(OH)2 surface was transformed into forsterite (Mg2SiO4) and chain or sheet-like silicate over the temperature range of 870–1100 °C, and the presence of the silica inhibited the sintering and crystallite growth of the MgO grains. At 1400 °C, these products were all transformed into forsterite, and the presence of the silica had little effect on the crystallite growth. (2) Hydrothermal treatment: Below 360 °C, the amorphous silicate on the surface crystallized as serpentine (Mg3Si2O5(OH)4), and the crystallite growth of Mg(OH)2 was inhibited. Above 420 °C, on the other hand, the silicate was transformed into forsterite through serpentine-like silicate, and the crystallite growth of Mg(OH)2 was promoted. The change in the crystallite size of the bulk by the treatment was interpreted mainly in terms of the behavior of the silicate on the surface.
Transition-metal Complexes of Pyrrole Pigments. XVII. Preparation and Spectroscopic Properties of Corrole Complexes
Authors: Murakami Yukito , Matsuda Yoshihisa , Sakata Kazunori , Yamada Sunao , Tanaka Yasuhiro , Aoyama Yasuhiro 
Published: July 2006

Abstract
Nickel(II), copper(II), and cobalt(III) complexes were prepared with corroles; 2,3,7,8,12,13,17,18-octaethylcorrole (OEC), 2,3,17,18-tetramethyl-7,8,12,13-tetraethylcorrole (MEC), and 8,12-bis[2-(ethoxycarbonyl)ethyl]2,3,7,13,17,18-hexamethylcorrole (PMC). For the coordination with nickel and copper ions, the corroles acted as dianionic ligands to yield electrically neutral complexes. These complexes exhibited metalloporphyrin-like electronic spectra, while they showed spectra which bear a much closer resemblance to those for metalloporphyrins as the anionic complexes were formed upon addition of alkali. The corroles coordinate to tervalent cobalt as trianionic ligands to form neutral complexes, which were reduced to the corresponding cobalt(II) complexes with sodium hydroborate. These reduced species gave a unique set of g-values (g1&gt;&gt;g2&gt;g3) for the complexes of macrocyclic ligands with conjugated double bond system. The plausible coordination geometry as well as the structural properties of the corrole ligands has been discussed.
Elementary Patterns in Protein–Nucleic Acid Interactions. II. Crystal Structure of 3-(Adenin-9-yl)propionamide
Authors: Takimoto Midori , Takenaka Akio , Sasada Yoshio 
Published: July 2006

Abstract
In order to study adenine-amide interactions, 3-(adenin-9-yl)propionamide has been synthesized and its crystal structure examined. The crystals are monoclinic, the space group being P21/a, with unit-cell dimensions of a=25.668 (1), b=8.025 (1), c=4.684 (1) Å, β=103.54 (1)°, and Z=4. The adenine bases are linked along the two-fold screw axis through the hydrogen bonds, N(6)H···N(1) and N(6)H···N(7). The amide group is hydrogen-bonded to N(3) of adjacent adenine moiety, the distance NH···N(3) being 3.055 Å. The model fitting by computer graphics indicates that this binding scheme could be an elementary interaction pattern between the amide group in protein and adenine in the minor groove of double helical DNA.
Energy Conversion and Storage in Solid-state Photogalvanic Cells
Authors: Hada Hiroshi , Takaoka Kazuchiyo , Saikawa Masahiko , Yonezawa Yoshiro 
Published: July 2006

Abstract
The solid-state photogalvanic cells involving photochemically deposited metals as active materials are presented. As these cells have many excellent features as compared with usual photogalvanic cells in which both the cathodic and anodic materials are dissolved in solution, they will promise a novel storage system for the conversion of solar energy to electrical energy. A typical two-compartment cell: TiO2, aqueous Ce(SO4)2–Ce2(SO4)3||aqueous AgNO3, Pt could be charged by the irradiation of 300–400 nm light on TiO2. The deposited silver on a platinum black storage electrode has almost the same electrochemical properties as the silver metal electrode and is capable of recharging after a nearly complete discharge.
Use of Propagators in the Hückel Model. II. Propagators in Terms of Trigonometrical Functions
Authors: Aono Shigeyuki , Ohmae Takayuki , Nishikawa Kiyoshi 
Published: July 2006

Abstract
The propagators of the chain molecules with and without the bond alternation are expressed in terms of trigonometrical functions. These expressions are convenient to practical manipulations. For exercises, the total energy, charge density and bond order are calculated.
Raman Scattering and Phase Transition of Ammonium Nitrates
Authors: Akiyama Kenji , Morioka Yoshiyuki , Nakagawa Ichiro 
Published: July 2006

Abstract
Polarized Raman spectra of single crystals are observed for the room-temperature phase NH4NO3(IV). The spectra in the low-frequency lattice vibration region as well as in the internal vibration region are well interpreted based on D2h13 structure. Raman spectra of powdered samples are measured at various temperatures covering whole phases NH4NO3 I–V. A characteristic feature of Raman spectrum is clarified for each phase. An abrupt spectral change occurs in the phase transition, indicating a first order transition. The splitting of Ag and B1g components of ν3 (asymmetric stretching mode of NO3− ion) in NH4NO3 is quite large, due to the strong interionic interaction between NH4+ and NO3− ions.
Raman Scattering and Phase Transition of NH4NO3–KNO3 Mixed Crystals
Authors: Akiyama Kenji , Morioka Yoshiyuki , Nakagawa Ichiro 
Published: July 2006

Abstract
NH4NO3–KNO3 mixed crystals, (NH4)xK1−xNO3 (x=0.88, 0.75, and 0.61), are prepared by evaporation of aqueous solutions of ammonium nitrate and potassium nitrate. Polarized Raman spectra of single crystals of mixed crystals are observed at room temperature and are interpreted based on the NH4NO3(III) type D2h16 structure. Raman spectra of powdered samples are examined at various temperatures and it is shown that the NH4NO3-(IV) type phase which is a room-temperature phase of NH4NO3 is not realized in the mixed crystals. In (NH4)0.88-K0.12NO3, NH4NO3(III) type is converted to NH4NO3(V) type around −120 °C. In the spectra of high-temperature phase of mixed crystals, only one broad band in the region 100 cm−1 −120 cm−1 is observed, which corresponds to KNO3(I) or KNO3(III) type structure.
Absorption Spectra of New Oxomolybdenum(V) Complexes of Tetraphenylporphyrin with Univalent Ligands
Authors: Imamura Taira , Numatatsu Takayuki , Terui Masashi , Fujimoto Masatoshi 
Published: July 2006

Abstract
New tetraphenylporphyrin complexes, MoO(tpp)X (X=F, Br, BF4, NCO, N3, and NCS), are easily prepared from the complex, MoO(tpp)OC2H5, where TPP denotes meso-tetraphenylporphyrin. The complexes are confirmed to contain a central oxomolybdenum(V) group based on the IR and the ESR measurements. The visible absorption spectra of the complexes in dichloromethane have three main peaks, the Soret band, the α and the β bands. The degree of red shifts of the corresponding absorption maxima is found to increase in the order: X=OC2H5&lt;BF4\simeqF&lt;NCO&lt;N3&lt;NCS&lt;Cl&lt;Br, accompanied with the same order of the change in the ratio εα/εβ. The correlation is also observed between the red shifts of the absorption peak around 330 nm and those of the Soret band. The complexes, MoO(tpp)X, are classified to d-type hyperporphyrin.
Reaction Process between Zinc Oxide and Sulfur Dioxide in the Presence of Carbon
Authors: Yajima Akimasa , Matsuzaki Ryoko , Saeki Yuzo 
Published: July 2006

Abstract
The reaction products obtained by heating a mixture of ZnO and carbon in a SO2 stream at various temperatures were examined. The possible reactions during the above process were also examined. When a mixture of ZnO and carbon was heated in a SO2 stream, the formation of ZnS was observed above 600 °C. At 800 °C, all the ZnO used was converted to ZnS. Sulfur was also obtained outside the heating zone, and its amount increased markedly above ca. 750 °C. The ZnS formed was a mixture of α-ZnS and β-ZnS regardless of the reaction temperature. The process of formation of ZnS can be represented as follows: the reaction between carbon and SO2 occurs at first to form sulfur. Above ca. 600 °C, the reaction between ZnO and the sulfur occurs to form ZnS. In addition to these reactions, the reduction of ZnO with carbon occurs slightly to form zinc, which then reacts with sulfur to form ZnS.
Catalytic Polarographic Wave of Fe(II) in Neutral Thiocyanate Solutions at Dropping Mercury Electrode
Authors: Himeno Sadayuki , Saito Atsuyoshi 
Published: July 2006

Abstract
The electrochemical behavior of Fe(II) in neutral thiocyanate solutions has been investigated at a dropping mercury electrode (DME). It was found that Fe(II) in neutral thiocyanate solutions gave a catalytic polarographic wave at potentials prior to the main Fe(II) reduction wave. The mechanism of the catalytic process involves the chemical reduction of thiocyanate ions with Fe(OH)2,aq at the electrode surface. Controlled potential electrolysis suggests that the reduction of thiocyanate ions proceeds with the formation of sulfide and cyanide ions. Sulfide ions produced at the electrode surface can react with Fe(II) diffusing to the electrode to form FeS. The discharge of this is responsible for the catalytic current, while cyanide ions have no essential role in the catalytic process. The effects of surface active substances and iodate ions on the catalytic wave are also discussed.
Oxidized Rubredoxin Models. Iron(III) Complexes of Z–Cys–Ala–Ala–Cys–OMe and Z–Ala–Cys–OMe
Authors: Ueyama Norikazu , Nakata Michio , Nakamura Akira 
Published: July 2006

Abstract
Oxidized rubredoxin models using Fe(III) ion and cysteine-containing peptide as Z–Cys–Ala–Ala–Cys–OMe were synthesized in solution and characterized by the absorption, CD, MCD, and EPR spectra. The Fe(III)/Z–Cys–Ala–Ala–Cys–OMe complex exhibits similar CD spectra as well as absorption, MCD, EPR spectra to native oxidized rubredoxin. Thus, the model complex has a similar electronic configuration and core structure to that of native protein. From the comparison with the result of Fe(III)/Z–Ala–Cys–OMe complex, the tetrapeptide complex probably has a relatively stable chelate structure with the hairpin turn conformation of the tetrapeptide.
Reaction of Dimeric Copper(II) Acetate with Pyridine and Quinoline Bases in Dioxane
Authors: Hasegawa Kazuo , Nakasuka Noriyuki , Tanaka Motoharu 
Published: July 2006

Abstract
Copper(II) acetate reacts with pyridine and quinoline bases in dioxane giving rise to adduct compounds, which were characterized by UV and EPR techniques. The reaction is formulated as follows:
Cu2(OAc)4+L\oversetK21\ightleftharpoonsCu2(OAc)4L,
where L denotes a free base and K21 is an adduct formation constant. Values of K21 range from 12 for quinoline or 2-picoline to 146 mol−1 dm−3 for 4-ethylpyridine. A linear free energy relationship is observed between the adduct formation and the protonation of bases in water except for sterically crowded bases.
Synthetic Studies of Rifamycins. III. The Partial Synthesis of Rifamycin Ansa-chain Compounds from Their Degradation Products
Authors: Nakata Masaya , Sakai Toshiya , Tatsuta Kuniaki , Kinoshita Mitsuhiro 
Published: July 2006

Abstract
The ansa-chain compound methyl [methyl 2,4,6,8,10,11,12,13,14-nonadeoxy-4,6,8,10,14-penta-C-methyl-3-O-methyl-l-manno-β-d-galacto-(11E,13Z)-11,13-pentadecadienopyranosid]uronate (1a) and its (R)-2-bromo derivative, 1b, were transformed into the corresponding 7,9-diacetate 3a and 3b or the 7,9-acetonide 7a and 7b. The ozonolysis of 3a or 3b gave methyl 7,9-di-O-acetyl-2,4,6,8,10-pentadeoxy-4,6,8,10-tetra-C-methyl-3-O-methyl-l-manno-β-d-galacto-undecodialdopyranoside-(1,5) (4a) or its (R)-2-bromo derivative (4b) respectively. The Wittig condensation of 4b with (methoxycarbonylmethylene)triphenylphosphorane, followed by debromination with tributylstannane, afforded methyl [methyl-7,9-di-O-acetyl-2,4,6,8,10,11,12-heptadeoxy-4,6,8,10-tetra-C-methyl-3-O-methyl-l-manno-β-d-galacto-(E)-11-tridecenopyranosid]uronate (6a). The diisobutylaluminium hydride reduction of 6a, followed by acetonation, gave methyl 2,4,6,8,10,11,12-heptadeoxy-7,9-O-isopropylidene-4,6,8,10-tetra-C-methyl-3-O-methyl-l-manno-β-d-galacto-(E)-11-tridecenopyranoside-(1,5) (10a). The allylic alcohol, 10a, was converted into the allylic bromide, 12a, which then yielded the triphenylphosphonium bromide, 13a. The Wittig condensation of the reactive ylide generated from 13a with methyl pyruvate afforded a 4 : 5 mixture of 7a and its 13E-isomer. The partial synthesis of 1a was accomplished by the selective hydrolysis of the 7a isolated from the mixture.
Synthetic Studies of Rifamycins. IV. The Synthesis of Rifamycin Ansa-chain Compound Using Carbohydratet
Authors: Nakata Masaya , Takao Hideaki , Ikeyama Yutaka , Sakai Toshiya , Tatsuta Kuniaki , Kinoshita Mitsuhiro 
Published: July 2006

Abstract
3-O-Benzyl-2,4,7-trideoxy-5,6-O-isopropylidene-2,4-di-C-methyl-l-glycero-d-galacto-heptose (6) was synthesized through 16 steps from 4,6-O-benzylidene-3-deoxy-3-C-methyl-α-d-altropyranoside (7). The condensation of 6 with methyl 2,4,6,7-tetradeoxy-6-lithio-4-C-methyl-3-O-methyl-α-l-arabino-(E)-6-heptenopyranoside, derived from 7, afforded a mixture (25) of methyl 9-O-benzyl-2,4,6,8,10,13-hexadeoxy-11,12-O-isopropylidene-4,8,10-tri-C-methyl-3-O-methyl-6-methylene-l-glycero-d-galacto-β-d-galacto-tridecopyranoside and its α-l-altro epimer in a 61% yield. The debenzylation of 25 by hydrogenolysis with palladium black, followed by homogeneous hydrogenation with tris(triphenylphosphine)chlororhodium(I) and the chromatographic isolation of the desired diastereomer, gave, after acetylation, methyl 7,9-di-O-acetyl-2,4,6,8,10,13-hexadeoxy-11,12-O-isopropylidene-4,6,8,10-tetra-C-methyl-3-O-methyl-l-threo-l-manno-β-d-galacto-tridecopyranoside-(1,5) (3) in a 19% yield. The hydrolysis of 3 followed by periodate oxidation and Wittig condensation with (methoxycarbonylmethylene)triphenylphosphorane, affords in a 79% yield, methyl [methyl 7,9-di-O-acetyl-2,4,6,8,10,11,12-heptadeoxy-4,6,8,10-tetra-C-methyl-3-O-methyl-l-manno-β-d-galacto-(E)-11-tridecenopyranosid]uronate, which is convertible into the title compound.
The Reaction of Acetophenones with Manganese(III) Acetate
Authors: Kurosawa Kazu , Yamaguchi Katsutoshi 
Published: July 2006

Abstract
The reaction of 4′-methoxyacetophenone with manganese(III) acetate in the presence of ammonium chloride yielded 2-chloro-4′-methoxyacetophenone (2a) and 2,2-dichloro-4′-methoxyacetophenone (3a). The reaction of 2a with these reagents gave 3a, 4′-methoxy-2,2,2-trichloroacetophenone, and 1,4-bis(4-methoxyphenyl)-2,2,3,3-tetrachloro-1,4-butanedione (8a). The reactions of 2a and 2-bromoacetophenone with manganese (III) acetate yielded the corresponding 2,3-dihalo-1,4-diphenyl-1,4-butanediones, 1,4-diphenyl-2-halo-2-butene-1,4-diones, 2,3-dihalo-2-butene-1,4-diones, 2,2-dibromoacetophenone, and 8a. The reaction pathways are discussed.
A Convenient Synthesis of Condensed Cyclopentane System. Annelation by Intramolecular 1,3-Dipolar Addition of Nitrones
Authors: Takahashi Satoru , Kusumi Takenori , Sato Yoko , Inouye Yoshinobu , Kakisawa Hiroshi 
Published: July 2006

Abstract
Intramolecular 1,3-dipolar addition reactions of nitrones were investigated. Four alkenyl nitrones were studied: 2-allyl-, 2-(3-butenyl)-, 2-(4-pentenyl)-, and 2-(9-decenyl)-N-methylcyclohexanimine N-oxides. Among these, 2-(3-butenyl)-N-methylcyclohexanimine N-oxide was found to cyclize most smoothly, giving a perhydroindene derivative as a single regio- and stereoisomer. A perhydroazulene derivative was obtained by cyclization of 2-(3-butenyl)-N-methylcycloheptanimine N-oxide.
Electronic Structures of Uracil and Its Anions
Authors: Morita Hiroshi , Kwiatkowski Józef S , Tempczyk Anna 
Published: July 2006

Abstract
Electronic structures of uracil and its anions were theoretically investigated by a modified CNDO-CI method. Theoretical results were in good agreement with the observed spectra of uracil and of both the uracil-3-ide and uracil-1-ide anions, indicating that the second π-π* band of uracil may tentatively be assigned to the 215 nm band observed in circular dichroism spectrum, and that the lowest singlet and triplet states of uracil are n-π* and π-π* states, respectively, in accord with the observed solvent dependence on emission properties. The first π-π* band of uracil-1-ide anion was correctly predicted by the method at longer wavelengths than the corresponding band of uracil-3-ide anion. For the purpose of comparison, a modified INDO-CI, CNDO/S-CI, and a modified π-SCF-MO-CI methods were also applied to the molecules under consideration. The results were only partly successful in predicting the observed spectra.
The Aluminium Ion-assisted Aquation of [CoF(NH3)5]2+
Authors: Iida Masayasu , Kai Eiko , Nishimoto Kichisuke , Yamatera Hideo 
Published: July 2006

Abstract
A kinetic study of the aluminium ion-assisted aquation of CoF(NH3)52+ was carried out. The pseudo-first order rate constant obtained can be expressed as kobsd=kAl[Al3+], where kAl=(1.6±0.2)×10−3 dm3 mol−1 s−1(I=2.0 mol dm−3, 25 °C). The reaction rate is independent of the pH in the (pH)obsd&lt;3.3 range, in contrast with the pH-dependent rate for the CrF(NH3)52+-Al3+ system. The different behavior between CoF(NH3)52+ and CrF(NH3)52+ in aquation can be explained in terms of their electronic structures, as calculated on the basis of the CNDO/2 method.
Structural Studies on the Cyclic Carbamate Derivatives of Kanamycin A
Authors: Takagi Yasushi , Komuro Chikara , Tsuchiya Tsutomu , Umezawa Sumio 
Published: July 2006

Abstract
Treatment of tetrakis(N-benzyloxycarbonyl)-6″-O-tritylkanamycin A with sodium hydride in N,N-dimethyl-formamide, followed by chromatography, afforded 4′,6′ : 3″,4″-, and 4′,6′ : 2″,3″-bis(cyclic carbamate) and 3″,4″-and 2″,3″-mono(cyclic carbamate) (2, 3, and others). The structures of the position isomers 2 and 3 were determined by the NMR spectra at 500 MHz of their N-tosyl-O-acetyl derivatives.