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The asymmetric unit of the title sulfodiimide, C22H22N2OS, consists of two crystallographically independent molecules with similar conformations The environment around each sulfur atom is a slightly distorted tetrahedron with two S=N bonds and two S—C bonds. The S= N(m-methylbenzoyl) and S=N(NEt) bond lengths are 1.584 (3) and 1.528 (2) Å, respectively, for one molecule, and 1.575 (2) and 1.529 (3) Å, respectively, for the other. The dihedral angles between the two phenyl rings in the molecules are 86.76 (8) and 82.49 (8)°. The N—S—N—C(m-methylbenzoyl) and N—S—N—C(ethyl) torsion angles are −60.5 (2) and −50.28 (19)°, respectively, for one molecule, and 62.9 (2) and 44.2 (3)°, respectively, for the other. In the crystal, each independent molecule is linked to its inversion-related molecule via a pair of C—H...O hydrogen bonds, forming a dimer.

The title salt, C24H27N2OS+·BF4 −, was prepared by an alkylation at the amino N atom attached to the sulfur atom of the corresponding sulfodiimide. The configuration around the sulfur atom is a slightly distorted tetrahedral geometry with two S—N bonds and two S—C bonds. The lengths of the S—N(diethylamine) and S=N(m-methylbenzoylimine) bonds are 1.619 (2) and 1.551 (2) Å, respectively. The two N—S—N—C(ethyl) and the N—S—N—C(m-methylbenzoylimine) torsion angles are −85.43 (3), 58.94 (17) and 62.03 (16)°, respectively. The dihedral angle between the two phenyl rings is 84.03 (14)°. In the crystal, C—H...F hydrogen bonds link the cation and anion, forming a three-dimensional network.

In the title compound [systematic name: N-(iminodiphenyl-λ6-sulfanylidene)-4-methylbenzene-1-sulfonamide], C19H18N2O2S2, the configuration around the sulfur atom of the sulfonediimine group is a slightly distorted tetrahedron structure with two S=N bonds and two S—C bonds. The bond lengths of S=N (p-toluenesulfonyl) and S=N (NH) are 1.5785 (15) and 1.5158 (18) Å, respectively. The S—N=S plane makes a dihedral angle of 74.24 (14)° with the p-toluene ring, while it makes dihedral angles of 73.43 (13) and 41.98 (14)° with the phenyl rings. The two torsion angles of S—N=S—C (phenyl) and the S—N=S=N angle are 105.86 (12), −144.54 (11) and −25.67 (17)°, respectively. In the crystal, molecules are connected by pairs of N—H...O hydrogen bonds, forming inversion dimers with an R 2 2(12) ring motif. The dimers are linked by C—H...O interactions, forming a tape structure along the a-axis direction.

The title compound, C12H9BrN2O2S, the first crystal structure of anN-halosulfimide, adopts asynconformation about the S=N bond, with a Br—N—S—C(phenyl) torsion angle of −54.64 (17)°. The dihedral angle between between the phenyl and 4-nitrophenyl rings is 65.04 (14)°. In the crystal, molecules are linked by C—H...Br, C—H...N and C—H...O interactions, forming a tape structure along thecaxis.

Dithianthren-1-ylmethanol and 1,1′-methylenedithianthrene were prepared and their reactions were studied. Lithiation of 1,1′-methylenedithianthrene took place on the methylene carbon rather than on the thianthrene framework, and when the lithiated derivative was allowed to react with thianthren-1-ylcarbaldehyde, sterically hindered 1,2,2-trithianthren-1-ylethanol was obtained in good yield. The structures of 1,1′-methylenedithianthrene and 1,2,2-trithianthren-1-ylethanol were confirmed by X-ray crystallography. To clarify the nature and reactivity of thianthrene derivatives, we also prepared 1,6-(thianthren-1,9-diyl)hexane-1,6-diol (5,6,7,8,9,10-hexahydro-1,14-epithiodibenzo[b,j]thiacycloundecine-5,10-diol) as a model compound in which the 1- and 9-positions of thianthrene are bridged by a carbon chain.

To establish a covalent chromatography system for purification of naturally occurring chymotrypsin-like serine proteases, a diphenyl 1-amino-2-phenylethylphosphonate derivative bearing Gly-Gly-Gly as a spacer was immobilized on the Sepharose 4FF gel. In this system, bovine chymotrypsin was selectively bound to the phosphonate immobilized on the gel and then released by the action of 2-pyridinealdoxime methiodide as the reactivated enzyme. Based on the study results for selective binding and reactivation conditions, chymotrypsin-like proteases from pancreatin (hog pancreas) were rapidly and highly purified within three hours. Keywords

The coupling reaction of 1-tributylstannylthianthrene (5) and 2-tributylstannylthianthrene (7) in the presence of copper catalysts at rt afforded the thianthrene dimer 1,1′-bithianthrene (3), 2,2′-bithianthrene (8), and 1,2′-dithianthrene (9) in high yields. Also we obtained thianthrene oxide dimer (R,R) (S,S)-1-(10-S-monoxythianthrene-1-yl)thianthrene-10-S-monoxide (12) and (R,S) (S,R)-1-(10-S-monoxythianthrene-1-yl)thianthrene-10-S-monoxide (13) from 1-tributylstannyl-10-S-monoxythianthrene (10) under the same reaction condition. The final structural conformation of 3, 8, 9, and 12 was performed by X-ray crystallographic analysis. Further, the solvent effects in the coupling reactions were also examined.

The reaction of 'active ester' bidentate cross-linking reagents, phthalimido 4-chloroformylbutanoate (1) and phthalimido 4-(2-benzothiazolyloxycarbonyl)butanoate (2) with several protected D-glucose derivatives is described. These reactions are used to introduce the reactive group into cellulose (filter paper) with the aim of linking proteins and cellulose.

Despite of the extensive study for peptide synthesis, DCC-mediated esterification is left still unclear. Therefore, DCC- and DCC/HOBt-mediated reactions of 3-phenylpropionic acid (1) with benzyl alcohol were carried out under several mechanistic considerations. Further, in order to determine the reactivities of the so-called ‘active esters’ compounds changing the substituents bearing carbonyl and related derivatives group for the purpose of the development of new class of non-symmetry cross-linkers, we have studied the reaction of model compounds, N-(3-phenylpropionyloxy)benzotriazole (6), N-(3-phenylpropionyloxy)phthalimide (7), 3-phenylpropionyloxybenzothiazole (8), and N-(3-phenylpropionyl)benzotriazole (9) with various nucleophiles under similar conditions were carried out for the comparison. It was revealed to exhibit the order of 6>>8>9>7.

In the course of our study of the development of a synthetic methodology for the aziridination of fullerenes, we recently reported the photochemical [2+1] cycloaddition reaction of nitrene onto C(60) generated from sulfilimine. Sulfilimines with an electron-donating group on the N atom are well known to undergo Michael-type reactions, followed by concomitant elimination of sulfide to afford the corresponding aziridines. In these reactions, sulfilimines act as a nucleophile to the electrophilic olefins. Furthermore, C(60) has characteristic features of a low LUMO level and electron-accepting properties. Therefore, it can be an electrophilic olefin. In this context, sulfilimines might react with C(60) to afford the corresponding aziridinofullerenes. We have studied the thermal reaction of (S,S)-diphenylsulfilimines with C(60) and regioselectively synthesized bis- and tris-aziridinated fullerenes. These structures were determined through spectroscopic analyses. Among these, the structure of bis-aziridinated[60]fullerene, C(60)(NCH(3))(2), was determined using single-crystal X-ray analysis. Results show that the multi-aziridination occurs exclusively at the same six-membered ring of C(60) to afford one isomer of the bis-adduct and tris-adduct.

To shorten the biological treating time and to examine the effect of electrolytes in a model water on the photocatalytic treatment, the combined biological-photocatalytic treatment was evaluated for removal of a mixture (total: 100 mg L-1, each: 25 mg L-1) of 2-chlorophenol (2-CP), 2,4-dichlorophenol (2,4-DCP), 2,4,5-trichlorophenol (2,4,5-TCP), and pentachlorophenol (PCP) in tap water. The mineralization of the four phenols was performed by a flow (biological treatment)-circulative flow (photocatalytic treatment) operation under black light and sunlight irradiations. After a large portion of biodegradable 2-CP and 2,4-DCP, and around half amount of slightly biodegradable 2,4,5-TCP were removed by the biological treatment, the remained three chlorophenols, biorecalcitrant PCP, and biodegradation products were completely removed by the subsequent photocatalytic treatment. The combined treatment significantly shortened the degradation time only the biotreatment. High circulative flow rate (600 mL min-1) enabled for TiO2 particles to completely suspend in a tubular photoreactor and resulted in high removals of chlorophenols and TOC. Sunlight irradiation was successfully used and the saving of the electric energy of black light was possible. Since TiO2 particles in the tap water spontaneously sedimented on standing after the photocatalytic treatment, the combined system can be operated by integrating it with the TiO2 separation. Keywords: photocatalysis, titanium dioxide, biodegradation, pollutant, wastewater

A study on the mechanism of the thermal decomposition of α- and β-heteroatoms substituted ethyl phenyl sulfoxides was carried out using 1-chloroethyl phenyl sulfoxide (1); two diastereomeric 1-acetoxyethyl (substituted phenyl) sulfoxides (2a) and (2b); and 2-chloroethyl phenyl, 2-bromoethyl phenyl, and 2-methoxyethyl phenyl sulfoxides (3, 4, 5). The rate of pyrolysis of 1 was 4.8 times faster at 160°C than that of ethyl phenyl sulfoxide used as a reference, while those of 2a and 2b were 107 and 155 times faster, respectively. The results indicate that the lone pair of electrons on the α-heteroatoms has a larger rate acceleration effect than the electronegativity of them. The substituent effects of the phenyl group of 2a and 2b gave positive Hammett ρ-values (ρ a = 0.76 and ρ b = 0.80 vs. σ). Activation parameters for 2a and 2b are as follows: 2a, ΔH ‡ = 112 kJmol−1, ΔS ‡ = −20 JK−1mol−1; 2b, ΔH ‡ = 107 kJmol−1, ΔS ‡ = −29 JK-1mol−1. Large deuterium kinetic isotope effects for 1-acetoxyethyl-2,2,2-d3 pheny...

Reaction of lithium salts, Li{E(SPh2N)2 } (E = CH (1− ), N(2− )) with diphenyltin dichloride in THF at –20 °C gave the corresponding tin-complexes [ClPh2Sn{E(Ph2SN)2}] (E = CH (3), N (4)) in good yields. The crystal structures of both compounds were determined by X-ray crystallographic analysis and showed to consist with a monomeric chelate structure that contains a distorted trigonal bipyramidal tin atom with a nitrogen and a chlorine atom in the axial sites. The chelated ligands in 3 and 4 adopt a boat and a twist boat conformation, respectively. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

The reaction of N-(3-phenylpropionyloxy)phthalimide (1a) and N-tosyloxy (5a,b) derivatives with nucleophiles was examined and found to give the products via Lossen-type rearrangement. In order to obtain the scope of this reaction mechanism, further studies the reaction of several N-sulfonyloxyimide derivatives with various nucleophiles under similar conditions were carried out and found to afford the corresponding same types of products in high yields.

The irreversible photolytic axial to equatorial change (3ax–4ax→3eq–4eq) and the irreversible thermal equatorial to axial change (3eq–4eq→3ax–4ax) of the S–O configuration were first observed. Meanwhile, the shorter 1,9-bridged derivative (2ax) exhibited the interesting photolytic degradation, affording 1,9-dithiadibenzothiophene (5) by the elimination of SO and ethylene.

The continuous mineralization of concentrated phenol (200 mg l(-1)) in an electrolyte-containing tap water was investigated using a biological-photocatalytic treatment integrated with TiO2 separation. Black light and sunlight were used as the light source, and the reuse of TiO2 was also studied. The mineralization of phenol in tap water and the reuse of TiO2 were conducted in a flow system in which a bioreactor is combined with a narrow tube photoreactor operated under single pass and circulative flows, and the sedimented TiO2 is recycled. A high circulative flow rate prevented the TiO2 particles from coagulating due to the electrolytes in the tap water. A flow-circulation-flow operation mode using the integrated biological-photocatalytic-TiO2 separation system was the optimum for treating the concentrated phenol in the electrolyte-containing tap water without interrupting the inflow of the wastewater and the discharge of the treated water. The optimum mineralization (phenol: 0.6 mg l(-1) and total organic carbon: 6.5 mg l(-1)) was attained by recycling the biologically treated phenol solution (20.1 mg l(-1)) at the flow rate of 600 ml min(-1) under sunlight irradiation, while maintaining the inflow and the discharge rates at 15 ml min(-1). The TiO2 particles were spontaneously sedimented by coagulation in a separation tank during the operation and the TiO2 can be reused without reducing the efficiency of five repeated treatments.

The reaction of fluorodiphenyl-λ 6 -sulfanenitrile with primary alkyl- or aryl-amines in the presence of acid catalysts or tertiary- amines gave N-monosubstituted S, S-diphenylsulfodiimides effectively.

The reaction of an N-unsubstituted S, S-diphenyl-sulfimide with aldehydes or ketones in the presence of a borane-pyridine complex and acetic acid in benzene at 40 °C affords the corresponding N-alkyl- S, S-diphenylsulfimides. Since this reaction does not form the N,N-dialkylated aminosulfonium salt, this method provides a convenient preparation of N-monoalkylsulfimides without the necessity for a difficult separation of the products by column chromatography due to their similar R f values. The mechanism of formation is discussed.

N -Sulfenylated sulfodiimides were first prepared by the reaction of S , S -diphenyl- N -tosylsulfodiimide with arenesulfenyl chlorides under the basic conditions. Thermolysis of S , S -diphenyl- N -(2-nitrophenylsulfenyl)- and S , S -diphenyl- N -(2,4-dinitrophenylsulfenyl)sulfodiimides in the presence of olefins proceeded at 50–80 °C to give the corresponding deiminated S , S -diphenyl- N -tosylsulfimide and N -sulfenylaziridines in very good yields. 2,4-Dinitrophenyl-sulfenylnitrene was trapped by trans - and cis -1-phenylpropenes stereospecifically. The thermolysis temperature of the N -sulfenylsulfodiimides was found to be lower than N -sulfenylsulfoximide and higher than N -sulfenyliminosulfonium salt and very effective to trap the sulfenylnitrene to give the N -sulfenylaziridines in very good yields.

The fluorination of 10-oxo-10 H -5λ 4 ,10λ 4 -thianthren-5-ylideneamine ( 2 ) with Selectfluor™ affords 5-fluoro-10-oxo-5,10-dihydro-5λ 6 ,10λ 4 -thianthren-5-nitrile ( 4 ). The amination of 4 with morpholine gives 5-morpholino-10-oxo-5,10-dihydro-5λ 6 ,10λ 4 -thianthren-5-nitrile ( 5 ). The stereochemical course of both reactions has been studied, while the configurations of their products, cis -isomer 4 and trans -5-morpholino-10-oxo-5,10-dihydro-5λ 6 ,10λ 4 -thianthren-5-nitrile ( trans - 5 ) are elucidated by the use of X-ray crystallographic analyses.

For site-selective chemical modification in the vicinity of the active site of chymotrypsin (Csin), a peptide derivative 1 bearing a diphenyl 1-amino-2-phenylethylphosphonate moiety for targeting t...

さまざまなデンプンをアセチル化することにより, 置換度の増加に伴うアセチル基の分布を検討した. アミロース含量の高いハイアミローススターチは, 低密度のアミロース部分からアセチル化が起こり, 低置換体ではアミロース部分にアセチル基が多く導入される. 一方, アミロース含量の低いデンプンは, アミロペクチンの構造によってアセチル基の分布が異なった. B型の馬鈴薯デンプンのアミロペクチンは分子鎖が長いため, アミロース分子とからみ合った部分が存在し, アセチル化はアミロースとアミロペクチンに同時に起こる. A型のコーンスターチはアミロペクチンの分子鎖が短いため, アミロースとアミロペクチンが単純な混合物として存在し, アセチル化はアミロース部分から進行する. しかしながら, アセチル化機構が異なっても, アセチル化デンプンの結晶構造には影響を与えなかった.

Alkoxy-λ6-sulfanenitriles were found to be versatile alkylating reagents toward various nucleophiles bearing at least one proton such as methanol, phenol, thiophenols, carboxylic acids, p-toluenesulfonic acid, hydrochloric acid, and primary and secondary amines. Reactivity of the alkoxy group of the λ6-sulfanenitriles showed an opposite trend to the usual SN2 character, i.e. Me (1a), Pr (1b), and Bu (1d) ≪ i-Pr (1c). In the presence of p-TsOH, alkyl tosylates were predominantly formed instead of the alkylation products of nucleophiles. In addition, even a sterically hindered substrate, neopentyloxy-λ6-sulfanenitrile, was found to undergo an SN2 reaction toward thiophenol without any rearrangement product to give neopentyl phenyl sulfide in good yield. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:193–198, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20006

Dithianthren-1-ylmethanol and 1,1′-methylenedithianthrene were prepared and their reactions were studied. Lithiation of 1,1′-methylenedithianthrene took place on the methylene carbon rather than on the thianthrene framework, and when the lithiated derivative was allowed to react with thianthren-1-ylcarbaldehyde, sterically hindered 1,2,2-trithianthren-1-ylethanol was obtained in good yield. The structures of 1,1′-methylenedithianthrene and 1,2,2-trithianthren-1-ylethanol were confirmed by X-ray crystallography. To clarify the nature and reactivity of thianthrene derivatives, we also prepared 1,6-(thianthren-1,9-diyl)hexane-1,6-diol (5,6,7,8,9,10-hexahydro-1,14-epithiodibenzo[b,j]thiacycloundecine-5,10-diol) as a model compound in which the 1- and 9-positions of thianthrene are bridged by a carbon chain.

Treatment of methyl(methylimino)diphenylsulfonium tetraphenylborate ( 3 ) with NaH and subsequent acylation produced a new type of iminosulfonium ylides bearing an α-carbonyl group 5 . The molecular structure of iminosulfonium phenacylide 5a was determined by X-ray crystallographic analysis. The ylide 5 reacted further with methyl triflate affording the corresponding novel alkylidenesulfonium salts 6 .

A kinetic investigation on the hydrolysis of aryl(fluoro)(phenyl)-λ6-sulfanenitriles was carried out in some aqueous and mixed aqueous-organic solutions. The pH-rate profiles showed that the hydrolysis consists of pH-independent, acid-catalyzed and base-catalyzed reactions. The neutral hydrolysis of fluoro-λ6-sulfanenitriles was found to proceed via an SN1 or an S-nitrilosulfonium cation-like transition state, which is characterized by a large negative Hammett ρ-value (ρ = −1.76 in water; −1.85 in CH3CN/H2O(1/4, v/v); −2.35 in TFE/H2O (1/1, v/v)), relatively large m-values (ca. 0.83 for fluoro(diphenyl)-λ6-sulfanenitrile; ca. 0.82 for fluoro(p-nitrophenyl)(phenyl)-λ6-sulfanenitrile against the solvent ionizing power YOTs-values in acetonitrile–water), a common ion effect in TFE/H2O, and a small salt effect. The large negative activation entropies (−60 – −101 J K−1 mol−1) were presumed to be due to strong solvation of F− with H2O in the reaction systems. The ease of ion dissociation of the S–F bond was exa...

Diphenyl(diphenylsulfodiimidoyl)(nitrido)sulfur(VI) (2) and diphenyl(diphenylsulfoximidoyl)(nitrido)sulfur(VI) (3) (Ph2XSNSNPh2N, X=NH, O) were prepared by the reaction of diphenyl(fluoro)(nitrido)sulfur(VI) (Ph2FSN) with sodium salts of diphenyl-sulfodiimide (Ph2S(NH)2) and -sulfoximide (Ph2OSNH). The nitrido-sulfur complexes 2 and 3 are considerably basic (pKa=7.86 and 7.60, respectively). Treatment of 2 and 3 with perchloric acid afforded quantitatively the corresponding μ-aza-bis[diphenyl(imido)sulfur(V)] perchlorate (4) and μ-aza-[diphenyl(imido)]-[diphenyl(oxo)]disulfur(V) perchlorate (5) ([Ph2XSNSPh2NH]+[ClO4]−, X=NH, O). The crystal structures of 4 and 5 were determined by X-ray crystallographic analysis. The former has essentially C2 symmetry with an SNS bond angle of 120.3(2)°, bridging SN bond lengths of 1.595(3) and 1.604(3) A, and terminal SN bond lengths of 1.509(3) and 1.497(3); the latter cation is an unsymmetrically substituted oxygen analog with an SNS bond angle of 123.1(2)°, and bridging SN bond lengths of 1.607(4) and 1.568(4) A, terminal SN and SO bond lengths of 1.501(3) and 1.438(2) A. Single-point ab initio calculations were also carried out using the data from the crystal structures of 4 and 5.

The hydrolysis of alkoxy(aryl)(phenyl)-λ6-sulfanenitriles in several buffer solutions was found to follow a good pseudo-first-order kinetic equation, giving the corresponding sulfoximides and alcohols (for the case of the hydrolysis of neopentyloxy-λ6-sulfanenitrile, giving a rearranged product, 2-methyl-2-butanol). The dependence of the rate of hydrolysis on the structure of the alkyl group showed the opposite trend to the usual SN2 character, i.e. Me < Pr < Bu ≈ Et < i–Pr, except for neopentyl. The pH-rate profiles indicated that the rate of hydrolysis is also first order in [H+] at pH more than 6.08, and trends to saturate at low pH. According to these kinetic results, a two-step reaction mechanism was proposed which involves a pre-equilibrium protonation on the nitrogen atom of the alkoxy-λ6-sulfanenitriles, followed by a rate-determining C-O bond cleavage via an SN2 or SN1 mechanism on the alkyl carbon atom depending on the structure of the alkyl group. From a double-reciprocal plot of 1/kobs vs. 1/[...

To develop a simple method to determine the degree of substitution (dS) for starch ester, we prepared starch acetate with various dS values (0—3) and examined the mode of starch-iodine complex formation for the starch acetate by monitoring the ultraviolet-visible (UV-vis) spectra and their Fourier-transform infrared (FT-IR) spectral changes. The effect of acetylation on the formation of the starch-iodine complex was investigated by monitoring the decrease in absorbance at 680 nm (blue value). The blue value decreased by increasing the standard dS value determined by NMR for starch acetate, but two different correlations between the blue values and the dS values were observed for the low- and highly-substituted starch acetate. The FT-IR spectra for starch acetate particles were measured using a diffuse reflection method. The peak areas and absorbances of the bands assigned to the acetyl group showed a poor correlation with standard dS values from the NMR. On the other hand, the FT-IR peaks assigned to sodi...

Previously we reported the novel thioaldehydes generation via thermolyses of phenacyl sulfoxides bearing some heteroaromatics. Thermolysis of sulfoxides (1a,b and 2a-4a) bearing other heterocycles such as thiadiazole, triazole, and tetrazole in the presence of 2,3-dimethyl-1,3-butadiene in dioxane at 100 degrees C led to the unexpected products 6-substituted-5,6-dihydro-3,4-dimethyl-2H-thiapyran 1-oxide (5a,b). These products were considered to be formed by the Diels-Alder reaction of the diene with the sulfines formed initially by the thermal decomposition of the sulfoxides. The rate acceleration and the improvement of the yield by addition of 1.5 equiv of triethylamine, especially in the case of ethoxycabonylmethyl sulfoxide 1c, was observed. The cis-trans selectivity for sulfine cycloadducts was also studied by NMR spectrometry. The reactions of alpha-substituted phenacyl sulfoxides 1d-f bearing a phenyl-substituted tetrazolyl group in the presence of the same diene were also studied.

In the study of the thermolysis of heteroaryl substituted sulfoxides, we examined the same reaction in the presence of several amines, such as aniline, benzylamine, and morpholine. In the case of 5-(1-phenyl)-1,2,3,4-tetrazolylsulfinylmethyl(dimethyl)phosphine oxide ( 1 ), the corresponding phosphinecarbothioamide 2 were unexpectedly obtained in moderate yields together with 1-phenyl-1,2,3,4-tetrazole ( 3 ). These products are considered to be formed by the addition reaction of amines to the sulfine formed initially and then elimination of H 2 O.

The thermal decomposition of melamine produces melame and meleme, while alkaline hydrolysis of melamine produces ammeline and ammelide. These four melamine derivatives were determined by high-performance cation-exchange chromatography using phosphate buffer as the eluent. The elution behavior during the isocratic and gradient elutions was examined and the determination was simultaneously achieved using photodiode array UV–Vis detection. An isocratic elution with 50 mM phosphate buffer (pH 2.5) seemed most suitable for the rapid and quantitative analysis. Three types of gradient elutions involving phosphate- and NaCl-concentrations, and pH also showed satisfactory separations for the melamine derivatives.

S-Alkoxy-S,S-diarylthiazynes were prepared by two methods: the alkaline hydrolysis of S,S-diaryl-N-halosulfilimines in aqueous alcohols and the reaction of S,S-diaryl-S-fluorothiazynes with sodium ...

The protective effect of guanidine hydrochloride (Gu-HCl) on the retrogradation of waxy corn starch (WCS) gel was studied using differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FT-IR), and solid-state 1H nuclear magnetic resonance (NMR). The areas of the endothermic peaks on DSC curves attributed to re-gelatinization of WCS gels became small and shifted to lower temperature with increasing Gu-HCl contents; finally, the endothermic peak for WCS gel containing 40% Gu-HCl disappeared, indicating that the WCS gel remained in the gelatinized state. The solid-state 1H NMR and FT-IR spectra for retrograded WCS gels showed significant changes compared with those for gelatinized WCS gels. In the process of retrogradation, these spectral changes should imply the formation of intra- and intermolecular hydrogen bonds of WCS and the increase of free water molecules. However, the 1H NMR and FT-IR spectra for a WCS gel containing 40% Gu-HCl did not show such changes along with the progre...

The pyrolysis of triphenyl (diphenoxyphosphinyl)phosphorimidate ( 1 ) was investigated using differential thermal analysis-thermogravimetry (DTA-TG), thermogravimetry-mass spectrometry (TG-MS), infrared spectroscopy (IR), mass spectrometry (MS), high performance liquid chromatography (HPLC) and the 31 P nuclear magnetic resonance method ( 31 P NMR). The cleavage of 1 by electron impact (EI) was also investigated, the results were used to elucidate the pyrolysis process. Compound 1 decomposed on heating to form phenol, triphenyl phosphate, hexaphenoxycyclotriphosphazene, octaphenoxycyclotetraphosphazene, triphenyl [ N -(diphenoxyphosphinyl)- P , P -diphenoxyphosphinimyl]phosphorimidate and longer-chain phosphazene compound (PhO) 2 P(O)NP(OPh) 2 NP(OPh) 2 NP(OPh) 3 . In mass spectrometric analysis, 1 was cleaved by the elimination of a phenoxyl radical, similar to pyrolysis, the formation of the ion assigned to triphenyl phosphate was observed.

Thermal reactions of phenacyl sulfoxide bearing heterocycles, such as a 2-benzothiazolyl or N-oxypyridyl group, in the presence of 2,3-dimethyl-1,3-butadiene afforded 6-benzoyl-5,6-dihydro-3,4-dimethyl-2H-thiapyran in good yield. This product is considered to be formed by the Diels−Alder reaction of a diene with thioaldehyde formed initially by the decomposition of sulfoxides.

粉末X線回折とフーリエ変換赤外分光分析(FT-IR)を用いて研究した.粘度は保存期間とともに増加した.一方,糊化前にGu-HC1を添加しても粘度は保存期間とともに増加し,添加量が多いほど粘度は低かった.膨潤した粒子の相互作用により,それら粒子は水素結合により網目構造を形成する.デソプンの粘度の増加率の長期的な増加は可逆的な結晶化と,貯蔵中の粒子間内の分子間水素結合と関係する.そこでこれらの老化した糊液のX線回折を測定すると,B型の結晶構造の回折線が観測された.また糊化直後と老化後の糊液のFT-IRを測定すると,水素結合を示す3000-3800cm-1の波数でピークの相違を観測し,五つのピークがこの波数内で重なり合っていた.これらの結果から老化の際に,Gu-HC1がワキシコーンスターチの分子構造に与える変化を提案し,模式図として示した.

Combustion tests show that polyamide-6 (PA-6) mixed with melamine is self-extinguishing. The thermal degradation process in PA-6 is modified strongly by the presence of melamine, so that the temperature of decomposition is lowered and the composition of the resulting volatile products is changed. On the other hand, melamine is not effective for either polypropylene (PP) or low-density polyethylene (LDPE). Activation energies based on thermogravimetry (TG) curves for the thermal decomposition of each sample at different heating rates are in the range of about 88.1 to 263 kJ mol −1 . The fluctuations found in activation energies indicates that a charring mechanism may contribute to the overall process. Minor amounts of thermal decomposition products other than ϵ-caprolactam were also evolved from the pure PA-6, their formation being suppressed in mixtures with melamine. The charring process occurs in parallel with the volatilization of decomposition products of PA-6, on which melamine seems not to have a significant effect. It appears evident that, compared with PP and LDPE, PA-6 is much more susceptible to thermal decomposition in the presence of melamine.

A new type of lambda6-sulfanenitrile with an SN triple bond at both ends, Ph2S(=N-(Ph2)S[triple bond]N)2 (5), was prepared in excellent yield from the one-pot synthesis of diphenylsulfimide (Ph2SNH) with fluoro(diphenyl)-lambda6-sulfanenitrile (Ph2FSN) in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene. Its molecular structure was determined by X-ray crystallographic analysis. Compound 5 reacted further with methyl triflate and trifluoromethanesulfonic anhydride to afford the corresponding bis-N-methylated and -N-sulfonated compounds.

Meleme, one of thermal decomposition products of melamine, ws analyzed satisfactorily by high-performance cation-exchange chromatography using 20 m M phosphate buffer as eluent. The elution behavior of meleme and melamine at various pH values (pH 2.0–6.0) was examined and the determination was accomplishes simultaneously using photodiode array UV-Vis detection.

The thermal decomposition and mass spectra of the N-phenyl- (1), N,N′-diphenyl- (2), and N,N′,N′-triphenylphosphoric triamides (3) were investigated. DTA-TG/DTG, TG-TRAP-GC/MS measurements, IR spectroscopic analyses, mass spectrometric analyses, HPLC analyses, and a kinetic study were carried out to investigate the thermal decomposition. From the analytical results, it was suggested that 1 decomposed while liberating ammonia and aniline, and condensed in several stages; its thermal products at about 160 °C contained 2. Compound 2 decomposed and condensed to form some condensed products at about 200 °C; its thermal products also contained 3. Compound 3 decomposed while liberating aniline to form a cyclic dimer, while the existence of other thermal products was also observed; the cyclic dimer further pyrolyzed in several stages, and 1 and 2 formed a similar condensed product in the 400 to 500 °C temperature range, though that for 3 was different. In addition, the apparent activation energy of the thermal de...