bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and Characterization of Manganese(III) Complexes with 2-{N-[2-(4-Imidazolyl)ethyl]iminomethyl}phenol or 2-{N-[2-(2-Pyridyl)ethyl]iminomethyl}phenol
Authors: Mikuriya Masahiro , Nukada Ryoji , Tokami Wataru , Hashimoto Youichi , Fujii Toshinori 
Published: June 2006

Abstract
Manganese(III) complexes with 2-{N-[2-(4-imidazolyl)ethyl]iminomethyl}phenol (HL1) or 2-{N-[2-(2-pyridyl)ethyl]iminomethyl}phenol (HL2), [MnL12]ClO4·CH3OH (1) and [MnL22]ClO4 (2), have been synthesized and characterized by infrared and electronic spectra, cyclic voltammetry, and temperature dependence of magnetic susceptibilities (80—300 K). The molecular structures of 1 and 2 were determined by single-crystal X-ray structure analysis. The manganese atom adopts an elongated octahedral geometry with two phenolic oxygen atoms, two imine nitrogen atoms, and two imidazolyl or pyridyl nitrogen atoms.
Structural Analysis of Cadmium–Glycylglycine Complexes Studied by X-Ray Diffraction and High Resolution 113Cd and 13C Solid State NMR
Authors: Takayama Toshio , Ohuchida Shirabe , Koike Yoshio , Watanabe Masanobu , Hashizume Daisuke , Ohashi Yuji 
Published: June 2006

Abstract
Structural analysis of bis(glycylglycinato)cadmium(II) complexes prepared to adjust the pH to 6 (A) and 9 (C), were studied by X-ray diffraction and high resolution 113Cd and 13C solid state NMR. In order to compare with the structure of A, structural analysis of bis(glycylglycinato)zinc(II) complexes (B) prepared to adjust the pH to 6 was also performed by the same methods. The structure of A was six coordinate; a five-membered chelate ring was formed between the terminal amino-group and the adjacent O (peptide) and the terminal carboxygroups of the dipeptide ligands were involved in Cd binding in the complex. The structure of B was similar to A, indicating that the Cd nucleus was better suited for probing the Zn nucleus-ligand structure. The structure of C was six coordinate; the four terminal carboxygroups (O) and the two terminal aminogroups (N) of the dipeptide ligands were involved in Cd binding in the complex. High-resolution 113Cd and 13C CP/MAS NMR spectra have been measured in order to obtain detailed information about the structures. The 113Cd signal of A showed a low field chemical shift compared with the peak of C. This means that the chelate ring shows decreased shielding. From the 13C spectra of A and C, it was seen that the Cd nucleus of A is bonded to a carbonyl oxygen (peptide) and the terminal carboxyl group of the dipeptide, but that for C is not bonded to a carbonyl oxygen (peptide).
Reaction Mechanism of Mercury(II) with Protonated N-Substituted Porphyrin
Authors: Nahar Nurun , Tabata Masaaki , Kaneko Kentaro 
Published: June 2006

Abstract
Kinetic and equilibrium studies on the complexation of mercury(II) ion with N-p-nitrobenzyl-5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin, (NO2Bz(Htpps)4−; HP4−) were carried out. The equilibrium constant, defined as KHgP = [HgP3−][H+][Hg2+]−1[HP4−]−1, was determined spectrophotometrically in the pH range 2—3 and at temperatures of between 15 and 35 °C. The value of KHgP was found to be 106.28 ± 0.04; and ΔH° and ΔS° values were 4.5 ± 0.7 kJ mol−1 and 134 ± 2 J mol−1 K−1, respectively at 25 °C. The kinetic studies were carried out under a pseudo-first order condition in an aqueous medium at 10—35 °C, I = 0.1(NaNO3), [HP4−] = 3 × 10−6, [Hg(II)] = 4.74 × 10−5 to 2.84 × 10−4, [acetate buffer] = 5 × 10−3 to 1 × 10−1 mol dm−3, and pH 4.2 to 5.6. The observed rate constant of the reaction was dependent of the total concentrations of mercury(II) and acetate buffer, but independent of the pH and ionic strength. The overall reaction was first order with respect to the total [Hg(II)] and [HP4−]. The rate expression of the reaction is d[HgP3−]/dt = (k1[Hg(OH)2] + k2[Hg(oac)2])[H2P3−]. The k1 and k2 values were found to be (1.26 ± 0.19) × 106 and (1.87 ± 0.01) × 106 mol−1 dm3 s−1 (25.0 °C), and the activation enthalpies and entropyies were ΔH‡ = 24.8 ± 3.8 kJ mol−1and ΔS‡ = −46 ± 13 J mol−1 K−1 for the k1, and ΔH‡ = 45.0 ± 2.1 kJ mol−1, ΔS‡ = 25.4 ± 7.4 J mol−1 K−1 for the k2. The kinetic data revealed that dihydroxomercury(II) directly reacts with the protonated porphyrin with a small activation enthalpy and a negative activation entropy.
Different Electrochemical Behavior of Complexes Having the Identical Nitroso Ligand in cis-[Ru(N,O-hia)(bpy)2]+ and cis-[Ru(N,O-hia)(bpy)(py)2]+ (hia: Hydroxyiminoacetylacetonato, CH3COC(NO)COCH3−)
Authors: Ooyama Dai , Nagao Noriharu , Kuroda Hiroshi , Satoh Utako , Howell F Scott , Mukaida Masao , Nagao Hirotaka , Tanaka Koji 
Published: June 2006

Abstract
[Ru(N,O-hia)(bpy)2]+ (I) and [Ru(N,O-hia)(bpy)(py)2]+ (II) (hia: CH3COC(NO)COCH3−) were prepared by the reactions of cis-[Ru(NO)(OH2)(bpy)2]3+ and cis-[Ru(NO)(OH)(bpy)(py)2]2+ with acetylacetone(Hacac) respectively. An X-ray structure analysis shows that the products have the identical nitroso ligand. Electrochemical behaviors of the complexes differ dramatically: I underwent an ECEC reaction, which could be illustrated as involving a structural rearrangement of the Ru-hia bonding, but II did not show such behavior and a typical reversible one-electron redox nature was found.
Hydrogenation of Biphenyl Using a Hydrogen Storage Alloy as a Hydrogenation Reagent
Authors: Nakagawa Shin-ichi , Murata Satoru , Nomura Masakatsu , Sakai Tetsuo 
Published: June 2006

Abstract
A detailed investigation of the hydrogenation reaction of biphenyl with MmNi3.5Co0.7Al0.8H4.2 [Mm: mixture of La, Ce, Pr, and Nd (30 : 52 : 5 : 13 wt ratio)] to give either cyclohexylbenzene or bicyclohexyl was performed. Time profiles of the amounts of hydrogen evolved from the alloy and that introduced into biphenyl during the reaction were measured; it was suggested that the hydrogen absorbed by the alloy could predominantly react with the substrate, and the hydrogen released into the gas phase played only a minor role in the reaction. The deuteration of biphenyl with the deuterated alloy, MmNi3.5Co0.7Al0.8D3.5, was also examined; a GC-MS analysis of the reaction mixture indicated that a H–D exchange between the hydrogen in the substrate and the deuterium in the alloy took place as a parallel reaction to hydrogenation of the aromatic rings, and, as a result, the product cyclohexylbenzene appeared to contain 3-9 deuterium atoms.
Synthesis and Reactions of Titanacycles Containing Group 14 Elements and Their Zirconium Analogues
Authors: Choi Nami , Morino Satoshi , Sugi Shin-ichiro , Ando Wataru 
Published: June 2006

Abstract
Lithium dimesitylgermanedithiolate reacted with titanocene or zirconocene dichloride to give 2,2-dimesityl-1,3-dithia-2-germa-4-titanacycle (3a) and its zirconocene analogue (3b), which afforded a stable 2,3,4,5-tetrathiagermolane (4) in treatment with S2Cl2. The reaction of 3b with Ph2GeCl2 gave unsymmetric 1,3,2,4-dithiadigermetane (5). The bis(η5-cyclopentadienyl) derivative of cis-2,3-di-t-butyl-2,3-diphenyl-1,4-dithia-2,3-disila-5-titanacyclopentane (7a) obtained from lithium 1,2-di-t-butyl-1,2-diphenyldisilane-1,2-dithiolate reacted with electrophilic reagents (SCl2, S2Cl2, Se2Cl2, R2GeCl2) to give the corresponding heterocycles.
The Synthesis, Antileukemic Activity, and Crystal Structures of Indirubin Derivatives
Authors: Li Chunmin , Go Yunhong , Mao Zihua , Koyano Kazuo , Kai Yasushi , Kanehisa Nobuko , Zhu Qingtai , Zhou Zhonghua , Wu Souyu 
Published: June 2006

Abstract
In order to search for a new kind of antileukemic drug, we synthesized four indirubin derivatives, including indirubin monooxime (IM), indirubin monooxime O-methyl ether (IMME), N1-methylindirubin monooxime O-methyl ether (MIMME), and indirubin monooxime O-ethyl ether (IMEE). Their antileukemic activities in vivo and in vitro were tested; some of these compounds showed good activities. Their molecular and crystal structures were determined by an X-ray diffraction method. The results revealed that all four indirubin derivatives are planar, and have a tendency to form a big π-system. The molecular structures also showed that oximation of indirubin resulted in only a slight change in the antileukemic activity. On the other hand, the amido moiety in the compounds may play an important role in the activity of the indirubin monooxime derivatives. This conclusion was supported by the calculation results of the electrostatic-potential (esp) derived charge distribution of the indirubin derivatives, which were obtained using an ab initio molecular orbital of the basis set (3-21G), taking the electronic correlation into account at the MP2 level.
Palladium-Catalyzed Acylcyanation of Terminal Arylacetylenes. Synthesis of 1,3-Diaryl-3-cyano-2-propen-1-ones and Tetrasubstituted Furans
Authors: Nozaki Kyoko , Sato Naomasa , Takaya Hidemasa 
Published: June 2006

Abstract
(Z)-1,3-Diaryl-3-cyano-2-propen-1-ones ((Z)-1) are prepared from arenecarbonyl cyanide and terminal arylacetylene in the presence of Pd(OAc)2–PPh3 (1 mol amt. to Pd)–0.5dppb (1,4-bis(diphenylphosphino)butane) (0.5 mol amt. to Pd). The reaction proceeded via the formation of acetylenic ketone 3, followed by the palladium-catalyzed addition of HCN, and isomerization of the resulting (E)-1 to (Z)-1. Oxidative addition of arenecarbonyl cyanide to zero-valent palladium metal has been observed by admixture of 4-MeOC6H4COCN to Pd2(dba)3 · CHCl3–PPh3–0.5dppb oxide (dppb oxide = Ph2P(O)(CH2)4P(O)Ph2). The resulting Pd(4-MeOC6H4CO)(CN)(PPh3)(ligand) afforded (Z)-1c by reaction with phenylacetylene. Thus, the role of two kinds of phosphine, PPh3 and dppb, suggests that the former acts as a ligand and the latter works as a reductant of Pd(II). The product (Z)-1 can be photoisomerized to (E)-1 under room light in CDCl3. The product (Z)-1 was obtained by a four-component coupling reaction of 4-iodotoluene, phenylacetylene, KCN, and carbon monoxide. A new synthesis of tetrasubstituted furans is also mentioned.
Production of Hydroxy Unsaturated Fatty Acids Using Crude Lipoxygenase Obtained from Infected Rice Plants
Authors: Kato Tadahiro , Watanabe Tsutomu , Hirukawa Toshifumi , Tomita Norihiro , Namai Tsuneo 
Published: June 2006

Abstract
In order to explore the oxidation mode of lipoxygenase (LOX) obtained from infected rice plants, typical unsaturated fatty acids (3—8) were treated with LOX and oxygen. It was observed that ω-10 and ω-6 positions of unsaturated fatty acids were oxidized predominantly in the cases of exotic ω-6 (4 and 5) and ω-3 (7 and 8) series, respectively. In the case of endogenous fatty acids (3 and 6), oxidation at ω-6 position predominated. All the allylic alcohols obtained by reduction of the oxidation products with NaBH4 possess S-configuration.
Synthesis of β-Lactams from Isocyanates and Vinyl Ethers under High Pressure
Authors: Taguchi Yoichi , Tsuchiya Tohru , Oishi Akihiro , Shibuya Isao 
Published: June 2006

Abstract
The [2 + 2]cycloaddition of phenyl isocyanate to 2,3-dihydrofuran was appreciably accelerated by compression to produce a β-lactam ring; its apparent activation volume was estimated to be −28 ml mol−1. Similar β-lactams were obtained under high pressure in the reaction of phenyl isocyanate with various vinyl ethers. Although the [2 + 2]cycloaddition of alkyl isocyanates to 2,3-dihydrofuran was also accelerated under high pressure to give β-lactams with good yields; the reactions of alkyl isocyanates with ethyl vinyl ether were slow, even at high pressure.
Preparation and Properties of 1,1′-Disubstituted Trichotomine Derivatives with a Twisted C=C Bond
Authors: Irikawa Hajime , Kanke Satoru , Mito Kousuke , Kobayashi Yasuhiro , Akasaka Tomoko , Atsumi Tadashi , Arimoto Hirokazu , Okumura Yasuaki 
Published: June 2006

Abstract
Green trichotomine derivatives bearing alkyl groups on C1 and C1′ were prepared. In their absorption spectra, the λmax shifted to longer wavelengths as the 1,1′-substituents became bulkier, and the bathochromism indicated twisting of the central C2=C2′ double bond. A 1,1′ -dimethyltrichotomine derivative underwent autooxidation to give orange-red 1,11b-dihydroxylated and 1,11b-seco-dicarbonyl compounds, in which twisting of the central C2=C2′ double bond might be relieved by the decreasing steric interactions between the substituents on C1 and the C3′ carbonyl groups.
NAD(P)+–NAD(P)H Models. 87. Nonsteric Stereochemistry Controlled by a Carbonyl Dipole
Authors: Ohno Atsuyoshi , Tsutsumi Akihiro , Yamazaki Norimasa , Okamura Mutsuo , Mikata Yuji , Fujii Masayuki 
Published: June 2006

Abstract
6,7-Dihydro-1,6,11-trimethyl-5-oxo-5H-benzo[c]pyrido[2,3-e]azepin-1-ium iodide (11-Me-MMPA+I−) was synthesized, and it was confirmed that the axial chirality in the salt is stable at room temperature. Upon the reduction of 11-Me-MMPA+ with a pair of diastereomeric dihydropyridine derivatives, the reacting face is always that in which the carbonyl dipole in the cation is included (i.e., syn selectivity), regardless the configuration of the reducing agent. A steric hindrance, in a classical sense, and other factors contribute to the stereochemistry of the reaction only in a minor part. Plausible intermolecular arrangements at the transition state of the reaction are discussed in order to understand the mechanism of this nonsteric stereochemistry.
Conformational Study on 2-Acyl-1-alkylidene-1,2,3,4-tetrahydroisoquinolines
Authors: Kitamura Masato , Tsukamoto Masaki , Takaya Hidemasa , Noyori Ryoji 
Published: June 2006

Abstract
The title enamide compounds can exist in either a sickle or U conformation with respect to the C=C–N–C=O conjugated moiety, where the sickle form is greatly favored. The sickle rotamers are chiral in nature in both solution and crystalline states, as proved by 1H NMR and a single-crystal X-ray analyses. The molecular distortion from the standard structure occurs in such a way as to retain the amide planarity, indicating a higher significance of the orbital interaction compared to the overlapping. The pathway and interconversion rate between the rotational stereoisomers are highly dependent on the nature of the 1-alkylidene and N-acyl groups. The energy barrier for the stereomutation of (Z)-2-(p-bromobenzoyl)-1-(3,4-dimethoxyphenylmethylene)-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline has been determined by a lineshape analysis of the 1H NMR spectra.
Lanthanide Ion as a Catalyst for Internucleotide Bond Formation
Authors: Sawai Hiroaki , Yamamoto Kenji 
Published: June 2006

Abstract
The lanthanide ion-catalyzed oligomerization of adenosine 5′-(1-imidazolylphosphate) was performed to yield short-chained oligoriboadenylates. The effect of lanthanide ions on the synthesis of oligoriboadenylates increased nearly in the order of the atomic number: None &lt; Nd3+ La3+ Ce3+ Pr3+ Sm3+ Eu3+ Gd3+ &lt; Tb3+ &lt; Dy3+ Ho3+ &lt; Er3+ &lt; Yb3+ &lt; Lu3+. The total yield of the oligoriboadenylates was 49% when Lu3+ was used as a catalyst. The linkage in the resulting oligoribadenylate was mainly 2′–5′.
A Fast Procedure for the Preparation of Amides/Peptides from Carboxylic Acids and Azides via Two Redox Reactions: Application to the Synthesis of Methionine Enkephalin
Authors: Ghosh Sunil K , Verma Rekha , Ghosh Usha , Mamdapur Vasant R 
Published: June 2006

Abstract
A one-pot self regulated approach for the synthesis of amides/peptides based on two reduction–oxidation (redox) reactions has been described. The primary and secondary amides/peptides are made by using azidotrimethylsilane and alkyl azides/α-azido acid derivatives respectively as the direct source of amine components. Benzeneselenol, generated in the reaction medium during carboxyl activation, has been found to be an effective reducing agent for the conversion of azides to primary amines. The methodology has been applied to the synthesis of methionine enkephalin.
Salt Effect on the Interaction of 22,24-Diprotonated 5,10,15,20-Tetrakis(4-sulfonatophenyl)porphyrin with a β-Sheet Structure of a Zwitterionic Polypeptide
Authors: Fukushima Yasumasa 
Published: June 2006

Abstract
The effect of sodium chloride on the absorption and CD spectra of the β-sheet structure of a zwitterionic poly(Glu–Val–Lys–Val)/22,24-diprotonated 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin system in aqueous solution was studied under various conditions. The monomeric TPPS was aggregated by the addition of the polypeptide and/or NaCl; at least four kinds of TPPS aggregation were observed. Although the aggregated species with an absorption band at around 489 nm formed an S-chiral conformation at [P]/[D] from 1 to 5 below 100 mM NaCl, the S-chirality changed to R-chirality by increasing to 500 mM NaCl or above. These results may indicate that an increase in the ionic strength induces a chiral conformational transition due to the prevention of electrostatic interactions between TPPS and the polypeptide; also the S-and R-chiralities could be caused by the secondary structure of the polypeptide and original property of TPPS, respectively. It is presumed that the electrostatic interactions play an important role in binding TPPS with the polypeptide as a major driving force. However, even 1000 mM NaCl could not completely shield the electrostatic interactions.
Rearrangement Approaches to Cyclic Skeletons. X. Pinacol-Type Rearrangement of 2-Substituted 1-Methoxybicyclo[2.2.2]oct-5-en-2-ols into Bicyclo[3.2.1]oct-6-en-2-ones. Remarkable Substituent Effects on Predominant Migration of the Unsaturated Bridge
Authors: Uyehara Tadao , Inayama Toshihiro , Furuta Toshiaki , Kato Tadahiro , Yamamoto Yoshinori , Ueno Masako , Sato Toshio 
Published: June 2006

Abstract
Pinacol-type rearrangement of 2-substituted 1-methoxybicyclo[2.2.2]oct-5-en-exo-2-ols (1) by treatment with p-toluenesulfonic acid in boiling benzene gave bicyclo[3.2.1]oct-6-en-2ones (2) and -3en-2-ones (4) in a ratio of ≥ 10 to 1 along with small amounts of dehydration products. Treatment of the endo isomers (3) under the same conditions gave 2, 4, and the dehydration products. The ratios of 2 to 4, in this case were within a certain range and were influenced by the substituent at the C-2 position. The ratio of the relative disappearance rate constant of 1 to that of the corresponding 3 was less than 10. This observation suggests that the unsaturated bridge does not offer remarkable anchimeric assistance in the reaction of 1. A similar acid treatment of the dehydration products gave 2 and 4 and their ratio was somewhat affected by the substituent. A mechanism is proposed for the pinacol-type rearrangement.
Synthesis of (3S,4S)-Statine and a Related Compound, (3S,4S)-AHPPA, from d-Glucosamine as a Chiral Pool
Authors: Shinozaki Katsuo , Mizuno Kazuhiro , Oda Hirohisa , Masaki Yukio 
Published: June 2006

Abstract
Biologically important threo-β-hydroxy-γ-amino acids, (3S,4S)-statine ((3S,4S)-4-amino-3-hydroxy-6-methylheptanoic acid) (1) and (3S,4S)-AHPPA (3S,4S)-4-amino-3-hydroxy-5-phenylpentanoic acid) (2), were synthesized starting from d-glucosamine (3) as a chiral pool. Two routes for the transformation of d-glucosamine to key intermediates, which are applicable to the synthesis of threo-β-hydroxy-γ-amino acids, were investigated. The successful route involved C(6)-carbon degradation and elimination of the C(4)-hydroxy group of d-glucosamine in 8 steps and 30% overall yield to furnish (4R,5S)-2-oxo-5-vinyloxazolidine-4-carbaldehyde dimethyl acetal (17), which has been utilized as a versatile intermediate for synthesizing the target compounds.
Intermediate Formation Process in Thermolysin Catalysis Observed Using a Fluorescent Displacement Probe in the Stopped-Flow Method
Authors: Kunugi Shigeru , Yokoyama Masahito , Kuroda Yasue , Yoshida Masumi , Koyasu Akira , Yamada Takashi , Sakamoto Akira 
Published: June 2006

Abstract
The thermolysin-catalyzed hydrolysis of N-Cbz-tripeptides was studied by means of a fluorescence stopped-flow method using N-dansyl-l-phenylalanine (Dns–Phe) as a displacement probe at lower pH.
To determine the probe features of Dns–Phe, the equilibrium and kinetics of the binary interaction between Dns–Phe and the enzyme were studied by means of static differential fluorescence and by fluorescence temperature-jump methods in the pH range 4.5—5.6.
The dissociation constant (Kd) increased along with an increase in pH. Both the decreasing (apparent) binding rate and the increasing (apparent) dissociation rate with increasing pH were attributed to this decline of complex formation at higher pH.
The pre-steady state process in the substrate hydrolytic reaction was studied with this displacement probe, and the observed rate constant for the four tripeptide substrates had saturation kinetics that indicated the existence of a new intermediate during the sequence of the enzyme reaction. Four tripeptide substrates had comparable k2 values (rate constant of intermediate formation), whereas the KS value of Cbz–Phe–Leu–Ala was about twice that of the others.
A Novel Trimerization of 1-Phenylsulfanyl-2,2,2-trifluoroethyl Isocyanide Giving a Dihydropyrimidine Derivative
Authors: Uno Hidemitsu , Oka Kenji , Tani Hiroyuki , Kawada Yoshihiro , Ono Noboru 
Published: June 2006

Abstract
1-Phenylsulfanyl-2,2,2-trifluoroethyl isocyanide (2a) readily and selectively trimerized to 4,6-bis(phenylsulfanyl)-1-(1-phenylsulfanyl-2,2,2-trifluoroethyl)-5-(2,2,2-trifluoroethylideneamino)-2-trifluoromethyl-1,2-dihydropyrimidine (5) at room temperature, while other α-phenylsulfanyl isocyanides such as phenyl(phenylsulfanyl)methyl isocyanide (2b) are stable. Heating of 2b resulted in formation of the corresponding nitrile as well as diphenyl disulfide and [bis(phenylsulfanyl)methyl]benzene.
Preparation of New Nitrogen-Bridged Heterocycles. 42. Synthesis and the Reaction of Pyridinium N-Ylides Using Bifunctional Ethyl Thiocyanatoacetates
Authors: Kakehi Akikazu , Ito Suketaka , Hashimoto Yasunobu 
Published: June 2006

Abstract
Various pyridinium (monosubstituted methylide)s were smoothly attacked to the cyano group in ethyl thiocyanatoacetate or ethyl 2-thiocyanatopropionate to afford the corresponding pyridinium (substituted cyanomethylide)s in low-to-moderate yields, while pyridinium (unsubstituted amidate)s reacted with the ester carbonyl group in the same reagents to give pyridinium (thiocyanatoaceto)- or (2-thiocyanatopropiono)amidates in considerable yields. The 1,3-dipolar cycloadditions of some pyridinium (unsymmetrically substituted cyanomethylide)s with dimethyl acetylenedicarboxylate (DMAD) in various solvents afforded only dimethyl 3-cyanoindolizine-1,2-dicarboxylate, except a few examples. On the other hand, the treatment of pyridinium (thiocyanatoaceto)- or (2-thiocyanatopropiono)amidates with a strong base, such as potassium t-butoxide, gave new bicyclic mesoionic compounds, N-[2-(1,3,4-thiadiazolo[3,2-a]pyridinio)]acetamidate derivatives, in moderate yields. The intermediacy of N-[1-(2-thiocyanatopyridinio)]acetamidates in the formation reactions of the latter compounds was also proven by independent syntheses.
Photodimerizations and Crystal Structures of Thymine Derivatives Having a Long Alkyl Chain Connected with a Carbamate Bond
Authors: Sugiki Takanori , Tohnai Norimitu , Wang Yuhua , Wada Takehiko , Inaki Yoshiaki 
Published: June 2006

Abstract
Photodimerizations of thymine derivatives having a long alkyl chain on a carbamate bond were investigated by irradiation of UV light at 280 nm in amorphous and crystalline film states. The amorphous films obtained by spin-coating from chloroform solution had higher initial rate constants for photodimerization relative to those of the crystalline films after annealing. X-Ray crystal structure analysis showed that the thymine derivatives had intermolecular hydrogen bonds that led to disadvantageous molecular orientation for the photodimerization. The photodimerization, however, is preferred in the localized layer structures of thymine units and alkyl chain.