bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Determination of Antimony in Water by Atomic-absorption Spectrophotometry Following Flotation Separation
Authors: Nakashima Susumu 
Published: July 2006

Abstract
A flotation method which utilizes an iron(III) hydroxide–surfactant–air system at pH 4 is described for the separation of sub-microgram levels of antimony(III,V) in water. The antimony content is determined by the generation of stibine, followed by atomic-absorption spectrophotometry with a long absorption cell (60 cm×1.2 cm i.d.).
Circular Dichroism Spectra and Absolute Configurations of cis,cis,cis-(C,N,O)-Dicyanobis(glycinato)cobaltate(III) and Dicyanobis-(β-alaninato)cobaltate(III) Complexes
Authors: Fujinami Shuhei , Shibata Muraji 
Published: July 2006

Abstract
The [Co(CN)2(NO)2]−-type complexes (NO: gly− and β-ala−), which have cis,cis,cis geometry with respect to the donor atoms C, N, and O, have been prepared by a new method, and resolved into their optical antipodes. The CD spectra of the resolved complexes have been measured, and compared with that of (−)589[Co(CN)2(ox)(en)]− complex which has the same chromophore with the bis(glycinato) complex. It is found that the optical activity of the cis,cis,cis-[Co(C)2(N)2(O)2]−-type complex mainly arises from the arrangement of the donor atoms; the non-ligating atoms of NO ligand make minor contribution to the optical activity.
Solvent Extraction of Iron(III) in Concentrated Nitric Acid with Several β-Diketones
Authors: Sekine Tatsuya , Komatsu Y\={u} , Inaba Kazuho 
Published: July 2006

Abstract
The solvent extraction of iron(III) in nitric acid (1 to 13.2 mol dm−3) with seven β-diketones into carbon tetrachloride was studied. The extraction curve has a pronounced minimum at from 6 to 7 mol dm−3 acid, and the extracted iron(III) species were assumed to be represented by FeAa(NO3)3−a(HA)n (where a and n are from 0 to 3).
A Facile Reduction of Copper(II) Leading to Formation of Stable Copper(I) Complexes. Redox Properties of Four- and Five-coordinate Copper Complexes
Authors: Sakurai Takeshi , Kimura Masazo , Nakahara Akitsugu 
Published: July 2006

Abstract
Schiff bases derived from 2-pyridinecarbaldehyde and 1,6-hexanediamine or bis(2-aminoethyl) disulfide gave stable Cu(I) complexes instead of Cu(II) complexes by reactions with copper(II) per chlorate. The facile reduction of copper(II) has been discussed on the basis of systematic comparisons of redox and ESR properties of about 20 complexes of similar structures.
The Reaction of cis-1,2-Dichloroethylene with Borane in Tetrahydrofuran. The Supply of Monochloroborane in a Tetrahydrofuran Solution
Authors: Arase Akira , Hoshi Masayuki , Masuda Yuzuru 
Published: July 2006

Abstract
In the reaction of cis-1,2-dichloroethylene with borane in THF at 20 °C for 2 h, about 94% of borane was converted to monochloroborane. The resulting solution was stable at 0 °C for several hours.
Photochemical Reactions of Azidotriazines with Aromatic Substrates
Authors: Tamura Shigeru , Imaizumi Hisao , Hashida Yoji , Matsui Kohji 
Published: July 2006

Abstract
Triazinylnitrene generated photochemically from 2-azido-4,6-dimethoxy-1,3,5-triazine adds to the aromatic ring of alkylbenzenes and halobenzenes to give N-triazinylazepines.
X-Ray Crystallographic Studies on the Structure of Alnuserrudiolone Isolated from the Male Flowers of Alnus serrulatoides
Authors: Hirata Toshifumi , Aoki Tadashi , Suga Takayuki 
Published: July 2006

Abstract
The structure of alnuserrudiolone was corroborated to be (12R,20S)-12,20-dihydroxy-24-methylenedammaran-3-one by the X-ray crystallography together with the 13C NMR and the high resolution mass spectral measurements.
Synthesis and Properties of O6-Substituted Guanosine Derivatives
Authors: Daskalov Hristo Petrov , Sekine Mitsuo , Hata Tsujiaki 
Published: July 2006

Abstract
Reactions of 2′,3′,5′-tri-O-acetyl-N2-protected or unprotected guanosine derivatives with phosphoryl, phosphinothioyl, arylsulfonyl, and silyl halides in dichloromethane gave the corresponding O6-substituted guanosine derivatives in good yields. In these reactions, 4-(dimethylamino)pyridine (DMAP) was found to be very effective catalyst. The physical data of these products and their stabilities under acidic and basic conditions were described in detail. Selective detritylation of O6-arylsulfonyl-N2-tritylguanosine derivatives was accomplished by treatment with 80% acetic acid. It was found that O6-dibutylphosphinothioyl derivatives were relatively stable under conditions where acetyl group was predominantly removed.
Crosslinked Polyvinylpyridine Hydrochloride as a Mild Polymeric Catalyst for Acetalization of Carbonyl Compounds and Esterifieation of Carboxylic Acids
Authors: Yoshida Jun-ichi , Hashimoto Jiro , Kawabata Nariyoshi 
Published: July 2006

Abstract
Crosslinked poly(4-vinylpyridine) hydrochloride was found to be an effective catalyst for acetalization of carbonyl compounds and esterifieation of carboxylic acids. The polymeric catalyst was inert to some acid sensitive functional groups which cannot tolerate under the influence of a strong acid cation exchange resin.
Preparations and Properties of Optically Active (Alkyl)bis(dimethylglyoximato)cobalt(III) Complexes
Authors: Ohgo Yoshiaki , Takeuchi Seiji , Natori Yukikazu , Yoshimura Juji , Ohashi Yuji , Sasada Yoshio 
Published: July 2006

Abstract
Optically active alkyl cobalt complexes, CH3CHXCo(Hdmg)2·Base [X=COOCH3 or CN; Base=(R)- or (S)-1-phenylethylamine, H2O, pyridine, or (1R,2S)-1,2-diphenyl-2-aminoethanol; Hdmg=dimethylglyoximate(1-)], have been prepared, and their spectroscopic and chiroptical data are given. The rotational contribution of the chiral alkyl moiety was shown to be considerably greater than that of the chiral amine moiety. This suggests that the rotational sign (in the longer-wave length region of about 546 to 589 nm) may be useful for deducing the chirality of the alkyl moiety.
The Synthesis of Thermally Stable Oils by the Benzylation of Biphenyl with Benzyl Chloride Catalyzed by Iron(III) Oxide
Authors: Hino Makoto , Arata Kazushi 
Published: July 2006

Abstract
The benzylation of biphenyl with various amounts of benzyl chloride was performed at 80 °C or at room temperature in the presence of iron(III) oxide prepared by calcining, at 300 °C, iron(III) hydroxide which has been precipitated by hydrolyzing FeCl3 with ammonia. The products with various viscosities were thermally stable up to 200–300 °C, and no chlorine was detected in the products.
The Effect of γ-Irradiation on the Biodegradability of Landfill Leachate
Authors: Sawai Takeshi , Sawai Teruko , Yamazaki Masao 
Published: July 2006

Abstract
A preliminary examination of the enhancement of biodegradability for landfill leachate, humic acid, and fulvic acid solutions, and aqueous solutions of polyethylene glycol-6000 by irradiation by 60Co γ-rays under aeration was performed. In all cases, the BOD5/TOC and BOD5/COD ratios increased with the dose. This suggests that the γ-irradiation modified these refractory materials to more biodegradable compounds.
Corrosion Inhibition and Adsorption Behavior of Some Thioamides on Mild Steel in Sulfuric Acid
Authors: Ateya Badr G , El-Anadouli B E , El-Nizamy F M A 
Published: July 2006

Abstract
The objective of this work was to evalulate the effect of changing functional and structural groups on the protection efficiency imparted by the various inhibitor molecules. It was found that the molecules which include a thiocarbonyl group e.g. thiourea (TU), thioacetamide (TA), and thiosemicarbazide (TSC) exhibited much higher protection efficiencies than the corresponding compounds which do not e.g. semicarbazide, guanidine, and aminoguanidine. Furthermore, it made only little difference whether the thiocarbonyl group was attached to two amino groups as in thiourea, an amino and a methyl group as in thioacetamide or an amino and a methyl group as in thioacetamide above certain concentrations both TU and TA lose their efficiency and eventually become corrosion promotors. The adsorption behavior of TU and TA was quist complicated whereas that of TSC points towards complete coverage at high concentrations. The differences in behaviour between TSC, TU, and TA have been explained on the basis of delocalization or resonance stabilization energy.
Preparation and Ligand Field Absorption Spectra of [CrF2(O–O)2]3− and [CrF2(O–O)(en)]− Type Complexes
Authors: Kaizaki Sumio , Akaho Mieko , Morita Yasuyo , Uno Kuniko 
Published: July 2006

Abstract
Two geometrical isomeric pairs of [CrF2(O–O)2]3− and either one of two possible geometrical isomers of [CrF2-(O–O)(en)]−, where O–O denotes oxalate and malonate anions, were newly prepared and characterized by means of the spectral and chromatographic elution behaviors. It was found that [CrF2(ox)(en)]− and [CrF2(mal)(en)]− obtained take cis and trans forms, respectively. The ligand field absorption spectra of the present complexes were compared with one another, and with those of the corresponding aqua complexes of the same type. On the basis of the analyses of the absorption spectra in terms of the angular overlap model, the AOM parameters (eσ and ex) for the ligands concerned were estimated, and their transferability assumption and the anisotropic π interactions of Cr–O bonding with respect to the chelate plane of the dicarboxylate ligands were discussed.
Iron Catalyst Local Concentration Fluctuations Found in Dissipative Reactions by X-Ray Microanalysis
Authors: Keszthelyi Csaba P , Soós József , Janossy András G S , Vovács Kristóf 
Published: July 2006

Abstract
The present work provides the first application of the powerful X-ray microanalysis technique in the study of “Zhabotinskii-type” oscillatory reactions. The modified HNO3: KBrO3: [Fe(phen)a]2+: malonic acid system is quantitatively described. Systematic variation, spatially correlated with the dissipative structures, was found in the Fe concentration.
Friedel-Crafts Acylation with 2-Methyl- or 2-Benzylbutanedioic Anhydride
Authors: Hashimoto Iwao 
Published: July 2006

Abstract
The AlCl3-catalyzed acylation of benzene with 2-methylbutanedioic anhydride afforded a mixture of 3-benzoyl-2-methylpropanoic acid and 3-benzoylbutanoic acid. The intramolecular acylation of 2-benzylbutanedioic anhydride in the presence of AlCl3 gave a mixture of 4-oxo-1,2,3,4-tetrahydro-2-naphthoic acid and 3-oxo-2-indanacetic acid. The results were discussed in terms of the solvent effect on the acylations.
The Synthesis of 2,5-Bis(p-methoxycinnamoyl)-1,3,4,6,7,8- and 4,5-Bis(p-methoxycinnamoyl)-1,2,3,6,7,8-hexamethoxyxanthene
Authors: Obara Heitaro , Onodera Jun-ichi , Saito Takashi , Sato Shingo , Shibata Tsutomu , Shibayama Kimio 
Published: July 2006

Abstract
In connection with studies of the structure of carthamin derivatives, 2,5-bis(p-methoxycinnamoyl)-1,3,4,6,7,8- and 4,5-bis(p-methoxycinnamoyl)-1,2,3,6,7,8-hexamethoxyxanthene were synthesized. The comparison of these two hexamethoxyxanthenes with carthamin derivatives is described.
Low-temperature Reaction of gem-Dihalocyclopropanes with Activated Magnesium
Authors: Ando Teiichi , Muranaka Takeshi , Ishihara Takashi 
Published: July 2006

Abstract
The reaction of 7-bromo-7-chlorobicyclo[4.1.0] heptane and 7-bromo-7-fluorobicyclo[4.1.0] heptane with activated magnesium in THF at −50 to −40 °C gave 7-bromobicyclo[4.1.0] heptane, in addition to 7-chloro- and 7-fluorobicyclo[4.1.0] heptane, respectively.
Use of 1,8-Diazabicyclo[5.4.0]undec-7-ene in Preparation of Trimethylsilyl Enol Ethers and Trimethylsilylacetylenes
Authors: Taniguchi Yoshiyuki , Inanaga Junji , Yamaguchi Masaru 
Published: July 2006

Abstract
Trimethylsilyl enol ethers were prepared by using a combination of chlorotrimethylsilane and 1,8-diazabicyclo[5.4.0]undec-7-ene in good yields. Trimethylsilylation of acetylenes was also achieved with the same reagents in the presence of silver salt as catalyst.
The Effect of Hydration on the Thermal Stability of Ovalbumin as Measured by Means of Differential Scanning Calorimetry
Authors: Fujita Yukihisa , Noda Yukinao 
Published: July 2006

Abstract
The thermal denaturation of ovalbumin (egg albumin) was investigated by means of differential scanning calorimetry in the water-content range from 0.11 to 1.15 g of water per g of protein. At water contents above 0.76 g/g, the temperature, Td, and the enthalpy, ΔHd, of denaturation were scarcely dependent at all on the water content. At lower water contents, however, both Td and ΔHd showed a marked dependence on the water content. The degree of the hydration dependence of the Td and ΔHd suggested that the amount of water required to hydrate ovalbumin was 0.76 g/g and that at least two types of the hydration phase contributed to the thermal stability of the protein.
1-Chloro-1,3-butadiene Copolymers. III. Reactivity of 1-Chloro-1,3-butadiene in Radical Copolymerizations
Authors: Kohjiya Shinzo , Takeuchi Hideo , Kawamoto Kohshi , Yamashita Shinzo 
Published: July 2006

Abstract
Radical copolymerizations of 1-chloro-1,3-butadiene (CB) were carried out with styrene (St), 1,3-butadiene (Bd), or chloroprene (Cp) in toluene at 70 °C by AIBN. The monomer reactivity ratios are found as follows: rCB=1.21±0.10, rSt=0.10±0.03; rCB=0.27±0.02, rBd=0.56±0.03. Copolymerization of CB and Cp showed CB was much less reactive than Cp. The Q and e values of CB were calculated to be 3.13 and +0.65, respectively. 1H NMR and IR of poly(CB-co-St) showed 60% of CB units are of 1,4-configuration and the rest 3,4-configuration.
The Hartree-Fock and Electron-Hole Potential Methods from a Hypervirial Theorem Standpoint
Authors: Isihara Makoto 
Published: July 2006

Abstract
The hypervirial theorem is introduced in the second quantized expanded form, and utilized for reviewing the Hartree-Fock and electron-hole potential methods. A possibility of going beyond the latter is suggested within the scope of handy methods. Brillouin’s and the extended Brillouin’s theorems are shown to be contained in the hypervirial theorem.
Mass-spectrometric Study of the Vaporization of Magnesium Oxide from Magnesium Aluminate Spinel
Authors: Sasamoto Tadashi , Hara Hiroshi , Sata Toshiyuki 
Published: July 2006

Abstract
The partial vapor pressures of Mg(g) over the spinel solid solution system, MgO·nAl2O3(n=1.0, 2.0, and 2.8), have been measured by the mass-spectrometric Knudsen-cell method. In the temperature range from 1850 to 2300 K, the pressures are described by these equations:
log[P(Mg,g)over 1.0-spinel/atm]=7.72±0.24−(26900±490)⁄T,
log[P(Mg,g)over 2.0-spinel/atm]=7.72±0.32−(27400±670)⁄T,
log[P(Mg,g)over 2.8-spinel/atm]=7.78±0.42−(27900±1220)⁄T.
These observed values were discussed in comparison with the calculated ones obtained by an approximate thermodynamic treatment of an ionic solid solution with composition-dependent vacancies.
Study on the Regeneration of Mn2O3 Catalyst for Simultaneous Abatement of NOx and SOx
Authors: Sato Toshio , Ueno Akifumi , Todo Naoyuki , Kurita Minoru , Hagiwara Hiroyuki , Nishijima Akiko , Kiyozumi Yoshimichi 
Published: July 2006

Abstract
A technique to regenerate catalysts used for the simultaneous abatement of NOx and SOx in flue gases was investigated. Formation of sulfate ions on the metal which is an active component of the catalyst was proved to be a poison for the catalysis. The most effective means to remove the sulfate ions on the catalyst is to heat the used catalyst at 300 °C in NH3–water vapor.
A Thermodynamic Study on Hydrolytic Reactions of Lead(II) Ions in an Aqueous Solution and Dioxane–Water Mixtures. II. A Calorimetric Study
Authors: Ishiguro Shin-ichi , Ohtaki Hitoshi 
Published: July 2006

Abstract
The hydrolytic reactions of lead(II) ions were calorimetrically studied at 25 °C in an aqueous solution and dioxane-water mixtures (dioxane contents: 0.1 and 0.2 mole fractions, which correspond to 35.21 and 55.01 % w/w, respectively) both containing 3 mol dm−3 (Li)ClO4 as a constant ionic medium. A fully automatic on-line system was used for the calorimetric titrations. Values of enthalpies and entropies for the formation of the Pb3-(OH)33+, Pb4(OH)44+, Pb3(OH)42+ and Pb6(OH)84+ complexes in the aqueous solution, 0.1 and 0.2 mole fraction dioxane solutions were given. For the reaction qPb2++pH2O=Pbq(OH)p(2q−p)++pH+, the values of ΔHpq*/kJ mol−1 and TΔSpq*/kJ mol−1 were determined as follows: Pb3(OH)33+ 66.6, −20.7 (in aqueous solution); 72.1, −13.4 (in 0.1 mole fraction dioxane solution); 66.9, −17.7 (in 0.2 mole fraction dioxane solution); Pb4(OH)44+: 81.4, −29.5;84.1,−22.1;94.7,−14.7; Pb3(OH)42+: 61.6, −68.4;83.4,−41.0,99.8,−24.3; Pb6(OH)84+:242.8, 1.3, 243.2, 10.6; 236.7, 2.0. The solvent effects on ΔHpq* were discussed in terms of a function of the formal charge per metal ion of the complex, z′=(2q−p)⁄q. The thermodynamic parameters obtained for the Pb6(OH)84+ complex were better explained by assuming the reaction, 2Pb3(OH)42+=Pb6O(OH)64++H2O, than the reaction, 2Pb3-(OH)42+=Pb6(OH)84+, and thus the Pb6(OH)84+ complex formally written from the result of the potentiometric measurements will be described as Pb6O(OH)64+ which has previously been proposed by X-ray diffraction.
A Reexamination of the Robinson Annelation of 2-Methylcyclohexanone with 3-Penten-2-one and 4-Phenyl-3-buten-2-one
Authors: Kikuchi Mitsuko , Yoshikoshi Akira 
Published: July 2006

Abstract
The reported Robinson annelation of 2-methylcyclohexanone with 3-penten-2-one has been reexamined. In contrast to the previous result, it was found that the reaction product was not only obtained in a low yield, but also the solvent-depending stereoselectivity in the formation of cis-4,4a-dimethyl-4,4a,5,6,7,8-hexahydronaphthalen-2(3H)-one (3a) and its trans isomer (3b) was considerably lower than that reported. As expected, regioisomers, 4β,8α-dimethyl-4,4aβ,5,6,7,8-hexahydronaphthalen-2(3H)-one and 4β,8β-dimethyl-4,4aα,5,6,7,8-hexahydronaphthalen-2(3H)-one, were also formed in the annelation. A similar tendency was observed in the reaction with 4-phenyl-3-penten-2-one. The annelation products, 3a, 3b, cis-4-phenyl-4a-methyl-4,4a,5,6,7,8-hexahydronaphthalen-2(3H)-one, and trans-4-phenyl-4a-methyl-4,4a,5,6,7,8-hexahydronaphthalen-2 (3H)-one, were also synthesized by an alternative route.
ortho-Disubstituted F-Benzenes. III. Preparation of (F-Benzo)heterocyclic Compounds from F-Benzoic Acid and F-Phenol, and the Reactions of Some Intermediary F-Benzoyl- and F-Phenoxy Compounds
Authors: Inukai Yoshinari , Oono Yoshitsugu , Sonoda Takaaki , Kobayashi Hiroshi 
Published: July 2006

Abstract
With the intention of achieving the selective ortho-substitution of F-benzoic acid and F-phenol via intramolecular nucleophilic cyclization, preparation of some requisite precursory F-benzoyl- and F-phenoxy compounds and their nucleophilic cyclization reactions were examined. 1,2-(F-Benz)isoxazol-3(2H)-one, 2-(p-tolyl)-1,2-(F-benz)isoxazol-3(2H)-one, 1,3-dimethyl(F-benzo)pyrimidine-2,4(1H,3H)-dione, and 1,4-(F-Benz)oxazin-3(2H)-one were obtained from the respective precursory F-benzohydroxamic acid, N-(p-tolyl)-N-hydroxy-F-benzamide, N,N′-dimethyl-N-(F-benzoyl)urea, and 2-(F-phenoxy)acetohydrazide. Attempted cyclizations of 2-(F-phenoxy)acetohydroxamic acid and (F-phenoxy) acetic acid were accompanied by simultaneous ring-opening and resulted in the formation of the identical product: (2-hydroxy-F-phenoxy)acetic acid. Transamidation of ethyl F-benzoate with hydroxylamine failed to give F-benzohydroxamic acid, which was then obtained by the catalytic debenzylation of N-benzyloxy-F-benzamide.
Reduction by a Model of NAD(P)H. 32. Stereoselective Reduction of Camphoroquinone by a Chiral NAD(P)H Model
Authors: Ohno Atsuyoshi , Goto Takehiko , Nakai Jun-ichi , Oka Shinzaburo 
Published: July 2006

Abstract
(+)-, (−)-, and racemic camphoroquinones (CQ) were reduced by each of four NAD(P)H-models such as N-(α-methylbenzyl)-1-propyl-2,4-dimethyl-1,4-dihydronicotinamide (Me2PNPH) in the presence of magnesium ion in acetonitrile with a view to elucidating the intermolecular arrangement in the transition state for asymmetric reduction. Partial rate factors for each attacking mode were calculated. Electronegative substituents in the substrate prefer to facing the carbamoyl group in Me2PNPH, which is the most important factor determining the stereochemical course of the reduction. 1-Methyl group in CQ has a tendency to interfere with the dihydropyridine moiety in Me2PNPH approaching the C2-carbonyl group in CQ. This interference is more important for the selectivity than the intrinsic exo/endo reactivity difference.
Reactions of Group V Metal Compounds with Sulfur Trioxide
Authors: Ando Fumio , Koketsu Jugo , Ishii Yoshio 
Published: July 2006

Abstract
Trialkylphosphines react with equimolar amounts of sulfur trioxide to form the 1:1 adducts R3P⊕–SO3\ominus. Trialkylarsines and -stibines undergo sulfur trioxide insertion reactions across the metal-carbon bond to give the trisulfonates of the metal M(OSO2R)3 (M=As, Sb). The reactions of trialkyl phosphites, with sulfur trioxide yield trialkyl phosphates, trialkyl thiophosphates, dialkyl alkylphosphonates, dialkyl sulfates, and polymers which contain phosphorus atoms. The reactions of trialkoxyarsines and -stibines result in the insertion of sulfur trioxide across the metal-oxygen bond to form the alkoxymetal alkylsulfates (RO)3−nM(OSO3R)n (M=As, Sb; n=1, 2, 3) depending on the stoichiometric ratios of the reagents used. Pyrolysis of the metal sulfates gives dialkyl sulfates and undistillable residues containing the metals.
Photochemistry of 9-[2-(N-Substituted Aminotnethyl)-1-naphthyl]phenanthrenes. Intramolecular Addition of Amines to Excited State of Phenanthrene in Conformationally Rigid System
Authors: Sugimoto Akira , Sumida Ryozo , Tamai Naoto , Inoue Hiroo , Otsuji Yoshio 
Published: July 2006

Abstract
Irradiation of benzene solutions of 9-[2-(N-substituted aminomethyl)-1-naphthyl]phenahthrenes (3a–d) gave pyrroline derivatives by the attack of the NH group on the C-9 carbon atom of the phenanthrene ring. The reactions were highly selective in regio- and stereochemical senses, and occurred through exciplexes formed by intramolecular interaction between the ammo group and the excited phenanthrene moiety in 3a–d. Mechanistic features of these photoreactions are discussed on the basis of chemical and photochemical properties of substrates and products.
Reactions of Ketone Hydrazones and β-Keto Enamines with Disulfur Dichloride. New Synthesis of Thioketones and 5H-1,2,3-Dithiazoles
Authors: Okazaki Renji , Inoue Kaoru , Inamoto Naoki 
Published: July 2006

Abstract
Ketone hydrazones react with disulfur dichloride in the presence of triethylamine to afford thioketones in good yields. The reaction mechanism involving N-thiosulfinylamine (R2C=N–N=S=S) and S-thioxothioketone (R2C=S=S) is proposed. The formation of t-butyl and di-1-adamantyl thioketones even at low temperatures has been interpreted as steric congestion alone being not enough to stabilize the corresponding S-thioxothioketones. The reaction of β-ketoenamines with disulfur dichloride gives 5H-1,2,3-dithiazoles via intramolecular cyclization of intermediary N-thiosulfinylamines.