bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultraviolet absorption spectra of some aromatic tricyclic ketones
Authors: Rekker R.F. , Nauta W. Th. 
Published: September 2010

AbstractThe UV absorption spectra of a small series of aromatic tricyclic ketones derived from benzophenone by introduction of an interconnecting ‐(CH2)n‐bridge (n = 1, 2, or 3) are described. The spectra show well‐defined steric effects in the 270‐nm region and they appear to be related to those of I‐indanone, I‐tetralone and similar structures with a corresponding band at about 240 nm. The band system is of conjugative origin and shows one single maximum ‐ with one exception: 10.11‐dihydro‐2,4‐dimethyl‐5H‐dibenzo[a.d]cyclohepten‐5‐one shows two separate maxima: at about 245 nm and 275 nm.
Phase transitions in copper chalcogenides II. The tellurides Cu3‐x Te2 and CuTe
Authors: Stevels A.L.N. , Wiegers G.A. 
Published: September 2010

AbstractThe thermal behaviour of the phases Cu3‐x Te2 and CuTe has been investigated by X‐ray diffraction at continuously varying temperature and by differential thermal analysis. Cu3‐x Te2 has an orthorhombic structure at room temperature which is closely related to the tetragonal structure of defective Cu2Sb type stable above 140°. Above 360° a face‐centred cubic form was found; the transition tetragonal ⇄ f.c.c. takes place via another (rhombohedral?) form. The atomic arrangements in the orthorhombic and f.c.c. forms have been studied. CuTe was found to disproportionate at 340° into Cu3‐x Te2 and a tellurium‐rich melt.
Synthesis and biological activity of four analogues of β‐corticotropin
Authors: Tesser G.I. , Buis J.T. 
Published: September 2010

AbstractThe syntheses of four ACTH‐analogues: [Orn15‐18]‐, [DSer1, Orn15‐18]‐, [Orn11‐15‐18]‐ and [DSer1, Orn11,15‐18]‐β‐corticotropin‐(1‐18)‐octadecapeptide amide** are described. The last mentioned compound exhibits an unexpected, strongly prolonged, biological activity. A possible explanation is given.
Conformation of non‐aromatic ring compounds part 69: An electron diffraction study of gaseous cyclopentanone
Authors: Geise H. J. , Mijlhoff F. C. 
Published: September 2010

AbstractThe gas‐phase molecular structure of cyclopentanone has been investigated. Bond lengths, valency angles and amplitudes of skeletal vibrations have been determined and were found to be normal. The puckering of the five‐membered ring, as given by Ømax = = 37.2 (or q = 0.38 Å), is less than in cyclopentane.
Hydrogenation and isomerization of unsaturated hydrocarbons catalysed by hydrogenated 1‐methylallyldicyclopentadienyltitanium(III)
Authors: Martin Hendrik A. , de Jongh R. O. 
Published: September 2010

AbstractHydrogenated 1‐methylallyldicyclopentadienyltitanium(III) in hydrocarbon solution is an active homogeneous catalyst for the hydrogenation of unsaturated hydrocarbons at room temperature. 1,3‐Dienes are not hydrogenated to completeness if they are capable of forming syn,syn‐1,3‐dialkyl‐substituted allyl complexes with the catalyst. 1‐Alkynes are not hydrogenated but polymerize rapidly to trans‐polyacetylenes. In the absence of hydrogen, 1,5‐cyclo‐octadiene is isomerized to the 1,3‐isomer via 1,4‐cyclo‐octadiene. Small amounts of hydrogen promote this double bond migration. 1‐Alkenes are converted selectively into 2‐alkenes at room temperature in a few minutes. Initially, the trans‐isomer is formed preferentially, followed by a slower trans‐cis isomerization.
An empirical investigation of the accuracy of virial equations for apolar and slightly polar vapours
Authors: Hammers W. E. , de Ligny C. L. 
Published: September 2010

AbstractThe applicability of the Berthelot, the Guggenheim‐McGlashan, the Pitzer‐Curl, the McGlashan‐Potter, and the Kreglewski virial equation to gas imperfection calculations has been examined empirically. For this purpose, calculated virial coefficients were compared with experimental data for a number of normal and branched alkanes, some polymethylenes, some aromatic and halogenated hydrocarbons, and ethers.
The oxidative conversion of toluene to benzene
Authors: de Jong J. G. , Batist Ph. A. 
Published: September 2010

AbstractAn oxidative reaction is described by which toluene is converted into benzene. The reaction is catalyzed by bismuth uranate. Selectivities up to 70% are obtained if toluene vapour reacts with the catalyst without gaseous oxygen being present; the catalyst becomes partially reduced, but can easily be reoxidized afterwards with air. Biphenyl and benzaldehyde have been identified as by‐products.
On the formation of allenes in the steroid series II. Synthesis and structure of several 19‐nor‐17,20‐pregnadienes
Authors: van Dijck L. A. , Lankwerden B. J. , Vermeer J. G. C. M. , Weber A. J. M. 
Published: September 2010

AbstractA number of 19‐nor‐pregnane derivatives bearing a 17,20‐diene side‐chain has been synthesized; the stereochemistry of the products formed during the preparation of non‐substituted, mono‐ and dimethyl allenes has been studied by means of application of Brewster's Rules and NMR spectroscopy.
Unconventional nucleotide analogues. V Derivatives of 6‐(1‐pyrimidinyl)‐ and 6‐(9‐purinyl)‐2‐aminocaproic acid
Authors: de Koning H. , Pandit U.K. 
Published: September 2010

AbstractBase‐catalyzed condensation of Nα‐benzyloxycarbonyl‐D,L‐lysine (1) with acrylamides 2a, b led to the formation of 2‐benzyloxy carbonylamino‐6‐(1‐pyrimidinyl)caproic acids 3a, b in good yields. Hydrolysis of 3a, b yielded the corresponding amino acids 4a, b. 6‐Chloropurine (9b) reacted with bromide 6b to give the N(9)‐ and N(7)‐substituted purines (10d and 11d). Subjecting 10d to the sequence: amination, hydrolytic decarboxylation, and deformylation, gave 6‐(9‐adeninyl)‐2‐aminocaproic acid 12a.
Stereoselective synthesis of eremophilane sesquiterpenoids from β‐pinene
Authors: van Der Gen A. , van Der Linde L. M. , Witteveen J. G. , Boelens H. 
Published: September 2010

Abstract2‐Methyl‐4‐isopropylidenecyclohexanone (7) can be obtained in good yield from β‐pinene (2) in a 5‐step sequence. Key step is the acid‐catalysed ring opening of cis‐3‐methylnopinone (5) to give 4‐(l′‐hydroxyisopropyl)‐2‐methylcyclohexanone (6, XOH). Robinson annulation of 7 with trans‐3‐penten‐2‐one proceeds stereoselectively to give α‐vetivone (10). Similar annulation of the isopropenyl isomer (8) affords 7‐epi‐nootkatone (11). 10 can be converted in good yield to nootkatone (13).
The nitration of mono‐alkylbenzenes conformational analysis and steric hindrance: Part II: Secondary alkylbenzenes
Authors: Baas J.M.A. , Wepster B.M. 
Published: September 2010

AbstractThe isomer distributions for the nitration of six secondary alkylbenzenes and the partial rate factors of three of these compounds have been determined. The steric hindrance of the nitration in the ortho‐position of isopropylbenzene is mainly of an enthalpic nature. The increase of this hindrance in the series of isopropylbenzene, s‐butylbenzene, (1‐ethylpropyl)benzene is of an entropic nature and can be explained from the conformational analysis of the initial states and the transition states. The steric hindrance in the ortho‐positions of (2‐methyl‐1‐ isopropylpropyl)benzene and (1‐t‐butyl‐2.2‐dimethylpropyl)benzene is very large.
The coordination chemistry of phenylbisdimethylaminophosphine oxide
Authors: de Bolster M.W.G. , Groeneveld W.L. 
Published: September 2010

AbstractA number of new solvates and adducts containing phenylbisdimethylaminophosphine oxide is reported. The solvates have the general formula M{C6H5P(O)‐[N(CH3)2]2}42+(anion)22−, in which M = Mg, Ca, Mn, Fe, Co, Ni, Cu, Zn and Cd, and the anions are ClO4− and BF4−. The adducts have the general formula MCl2{C6H5P(O)[N(CH3)2]2}n, in which M = Mg, Ca, Mn, Co, Ni, Cu, Zn and Cd, and n = 2, except for the Cd compound in which n = 3.The compounds are characterized and identified by chemical analyses and physical measurements.Vibrational spectra in the region 4000‐200 cm−1 have been investigated. A tentative assignment is proposed and the shifts of some ligand bands upon complexing are discussed. It is concluded that coordination takes place via the oxygen atom.Ligand‐field spectra for the complexes of Mn(II), Fe(II), Co(II), Ni(II) and Cu(II) have been investigated. Values for the ligand‐field parameters are reported.X‐ray powder patterns were used in combination with ligand‐field spectra to deduce the coordination around the metal ions.By a comparison of the ligand properties of phenylbisdimethylaminophosphine oxide, hexamethylphosphoramide and triphenylphosphine oxide the importance of steric factors in coordination chemistry is again demonstrated.
Synthesis of 4‐alkyl‐2‐hydroxy‐2‐methyl‐4‐butanolides and 4‐alkyl‐2‐methyl‐2‐buten‐4‐olides
Authors: Klaren‐De Wit M. , Frost D. J. , Ward J. P. 
Published: September 2010

Abstract4‐Ethyl‐ and 4‐isobutyl‐2‐methyl‐2‐buten‐4‐olide have been prepared by reaction of 2‐butanone and 4‐methyl‐2‐pentanone with sodium pyruvate, followed by reduction of the 2‐hydroxy‐2‐methyl‐4‐oxoalkanoic acids obtained, and lactonization to 4‐alkyl‐2‐hydroxy‐2‐methyl‐4‐butanolides. Treatment with triphenylphosphine in carbon tetrachloride caused extensive desaturation.The stereochemistry of the cyclic hydroxy and chloro intermediates was determined from the 220 MHz NMR spectra of the 4‐isobutyl derivatives.
Isomerisation of s‐triazolo [3,4‐a]isoquinoline and s‐triazolo[4,3‐a]thieno[3,2‐c]pyridine
Authors: Hoogzand C. 
Published: September 2010

AbstractThe novel heterocyclic compounds s‐triazolo[5,1‐a]isoquinoline, IIa, and s‐triazolo [3,2‐c]pyridine, IV, together with a few derivatives have been synthesized by isomerisation of the corresponding [3,4‐a] isomers by base in ethylene glycol/water. The spectral properties are discussed.
Pyrazoles and imidazoles as ligands. Part VII.N‐n‐butylimidazole as a ligand to metal(II) halides and isothiocyanates
Authors: Reedijk J. 
Published: September 2010

AbstractA number of compounds of formula M(Nn BuIz)n(anion)2 are described, the metal ions being Mn, Fe, Co, Ni, Cu, Zn and Cd and the anions Cl−, Br−, I− and NCS−; Nn BuIz stands for N‐n‐butylimidazole and n = 1–6.The compounds are prepared from the corresponding metal salts and the ligand in ethanol, and are characterized by chemical analyses and physical measurements.The ligand Nn BuIz is shown to coordinate with metal ions via the lone pair electrons of the pyridine‐nitrogen of the five‐membered ring. Metal(II) ions are found to be (pseudo)‐octahedral six coordinate for all compounds having n = 6 and n = 4, and for the Cu(II) compounds with n = 1 and 2. The remaining compounds with n = 2 have tetrahedrally coordinated metal ions.
Pyrazoles and imidazoles as ligands. Part VIII: Mössbauer spectra of octahedral Fe(II) solvates containing substituted pyrazoles and imidazoles as ligands
Authors: Reedijk J. 
Published: September 2010

AbstractMössbauer spectra are reported and discussed for a number of compounds of formula Fe(ligand)6(anion)2, with pyrazole, 3(5)‐methylpyrazole, imidazole, N‐methylimidazole and N‐n‐ butylimidazole as ligands, and ClO4−, Br− and I− as anions.The values found for the isomer shift (δ) and the quadrupole splitting (ΔEq) are in agreement with high‐spin iron(II) in a distorted octahedral coordination.The magnitude of δ, being 1.32 ± 0.02 mm/s, in these compounds is rather small and occurs at the lower site of the range usually found for octahedral iron(II).For closely resembling compounds a relation is found between ΔEq and the value of the magnetic moment.The author is indebted to Drs. D. W. Engelfriet, D. Knetch and Ir. A. M. van der Kraan for assistance with the measurements, and to Dr. A. M. van der Kraan for assistance with the measurements, and to Dr. W. L. Groeneveld for his interest in this study.
Resolution, optical rotatory dispersion, and absolute configuration of 1,3‐bis(2‐piperidyl)propan‐2‐one (anaferine)
Authors: Beyerman H. C. , Maat L. , Moerman C. A. 
Published: September 2010

Abstract(±)‐1,3‐Bis(2‐piperidyl)propan‐2‐one was resolved with the aid of the enantiomeric 6,6′‐dinitrobiphenyl‐2,2′‐dicarboxylic acids. Both optical rotatory dispersion measurements and chemical correlation showed the laevo‐rotatory compound to be (‐)‐(R,R)‐1,3‐bis(2‐piperidyl)propan‐2‐one, (‐)‐anaferine.
Sulfonyl‐stabilized phosphonium ylids
Authors: van Leusen A. M. , Reith B. A. , Iedema A. J. W. , Strating J. 
Published: September 2010

AbstractTwo general methods are given for the synthesis of mono‐sulfonyl‐substituted methylenephosphoranes, magnified image (1). (i) Methylenetriphenylphosphorane can be substituted by using sulfonyl fluorides to give 1. A similar reaction with sulfonyl chlorides, however, fails mostly, (ii) The synthesis of sulfonylmethyltriphenylphosphonium bromides (5) from bromomethyl sulfones and triphenylphosphine, due to Speziale and Ratts, was improved. The bromides 5 were readily transformed to 1 by base.As an extension of (i), the reaction of benzylidenetriphenylphosphoranes with sulfonyl halides has been studied. Contrary to previous reports it was found that the product from ethoxycarbonylmethylenetriphenylphosphorane and tosyl chloride is α‐ethoxycarbonyl‐p‐tolylthiomethylenetriphenylphosphorane, instead of the corresponding tosyl compound. Method (i), however, does not apply to ethoxycarbonylmethylenetriphenylphosphorane (16).
Electron spin resonance of complexes of pentacyanocobaltate(II) with aromatic nitro and nitroso compounds
Authors: Basters J. 
Published: September 2010

AbstractBy means of ESR techniques a systematic study has been made of radicals prepared by reaction of aromatic nitro and nitroso compounds with pentacyanocobaltate(II). Assignments of hyperfine coupling constants have been confirmed by deuterium substitution. The structure of the radicals, aryl pentacyanocobalt nitroxides, has been confirmed by experiments with nitro, corresponding nitroso and dinitro compounds and experiments with varying cobalt‐substrate ratio. Substituent effects on the nitrogen hyperfine interactions have been expressed in terms of a Hammett relationship aN = −1.46 σ ± 13.79. A qualitative ligand‐field model is given to get a better understanding of the delocalization of the unpaired electron over the transition metal ion and the aromatic ligand.
Chemistry of acetylenic ethers 95: Photochemical additions of acetylenes II reactions of ketones with 1‐alkynyl ethers
Authors: Bos H. J. T. , van der Bend H. T. , Boleij J. S. M. , Everaars C. J. A. , Polman H. 
Published: September 2010

AbstractPhotoaddition of aromatic ketones to 1‐alkynyl ethers R ′O ‐ C  C ‐ R generally affords, via C3O‐cycloaddition (oxete derivatives) alkyl 3,3‐diarylacrylates: Ar2C = CR ‐ COOR′in good yields (R = H,CH3,C2H5;R′ = CH3,C2H5).Analogously from acetone and 1‐methoxy‐1‐propyne, methyl 2,3‐dimethyl‐2‐butenoate (CH3)2C = C(CH3)COOCH3 was obtained, together with RH‐adduct III and an isomerised analogue IV.In two cases some 1,3,5‐triethoxybenzene, resulting from trimerisation of ethoxyethyne, could be isolated.
CIS‐ and trans‐1‐chloropropene vibrational assignment; coriolis interaction
Authors: Berg G. C. V. D. , Elst R. 
Published: September 2010

AbstractInfrared spectra of the gaseous state and Raman spectra of the liquid state of cis‐ and trans‐1‐chloropropene are recorded in the 100‐4000 cm−1 region. Vibrational assignments are given for both isomers.Vibration‐rotational analysis of the spectrum of trans‐1‐chloropropene made it possible to calculate four Coriolis coupling constants.
Solutes in sulfuric acid 4: Ionization of arenesulfonic acids; determination of pKa values by UV techniques
Authors: Cerfontain H. , Schnitger B. W. 
Published: September 2010

AbstractThe ionization of several aromatic sulfonic acids in aqueous sulfuric acid has been measured by means of UV techniques. The sulfonic acid ionization does not follow the aniline Ho acidity function, but the benzophenone Hao and the HA acidity functions. On the basis of the Hao scale, the pKa of benzenesulfonic acid is −6.65 ± 0.05. Substituent effects on the ionization of the sulfonic acid group are small; the Hammett ρ‐value was estimated to be 0.7 ± 0.2.
Liquid‐phase CO‐oxidation of aldehydes and olefins radical versus non‐radical epoxidation
Authors: Vreugdenhil A. D. , Reit H. 
Published: September 2010

AbstractIn co‐oxidations of aldehydes and olefins with molecular oxygen in the liquid phase, epoxides are formed via two different routes: (1) by reaction of intermediate acylperoxy radicals with the olefin, and (2) by a non‐radical reaction of intermediate peracid with the olefin. For the systems benzaldehydecis‐1, 2‐D2‐1‐octene and benzaldehydecis‐ andtrans‐2‐octene the ratio of radical to non‐radical epoxidation has been calculated with the aid of the kinetic relationships derived for this type of reaction and has been determined experimentally from the stereo selectivity of the expoxidation and from the production of carbon dioxide. The results show that the ratio of radical to non‐radical epoxidation increases with increasing reactivity of the olefin as well with increasing olefin/aldehyde ratio.
Studies of inter‐ and intra‐molecular donor‐acceptor interactions ‐ X: Intramolecular Charge transfer interaction in substituted N‐aralkyl‐phthalimides and ‐1,8‐naphthalimides
Authors: Craenen H. A. H. , Verhoeven J. W. , de Boer Th. J. 
Published: September 2010

AbstractCompounds D‐(CH2)n‐A (n = 1‐5) are studied, in which D = an aromatic group with low ionization potential (e.g. an electron donor) and A is mainly the N‐3,6‐dinitro‐1,8‐naphthalimide group. Especially for n = 1 and n = 3, interaction between D and A leads to the observation of discrete intramolecular C(harge) T(ransfer) transitions in the electronic absorption spectra. For n = 1 this is explained by “homoconjugative” interaction, while for n = 3 the molecules probably adopt a folded conformation, a suggestion which is suppported by NMR data. For n = 2 close approach of D and A seems to be sterically excluded, while for n > 3 the interaction between D and A rapidly diminishes. For the compound with D = 9‐anthryl and n = 3 steric interaction between the peri‐hydrogens of the anthryl group and the trimethylene chain seems to inhibit the molecule from adopting a folded conformation. For the compounds with D = p‐dimethylaminophenyl and n = 3 or 4 a double intramolecular CT transition is observed; a tentative explanation for this phenomenon is given.
Réactions D'Hétérocycles Oxygénés avec les Trialcoylsilyl‐, ‐Germyl‐ et ‐Stannyl‐Phosphines: II. Cas des lactones et des anhydrides d'acide
Authors: Couret C. , Escudié J. , Satgé J. 
Published: September 2010

AbstractThe trialkyl‐silyl‐, ‐germyl‐ and ‐stannyl‐phosphines R3MPEt2 react with β‐propiolactone via the cleavage of the alkyl‐oxygen bond of the lactone, leading to the trialkylmetal β‐diethylphosphinopropionates R3MOCOCH2CH2PEt2 (M = Si, Ge, Sn). These reactions are accompanied by a strong polymerization of the β‐propiolactone.The germyl‐ and silyl‐phosphines cleave γ‐butyrolactone at a rather high temperature and in the presence of catalyst (ZnCl2). Only the acyl‐oxygen scission is observed in this case, with formation of the phosphorated kétoalkoxymetal derivatives R3MO(CH2)3COPEt2. Under the same conditions, the stannylphosphines decompose before reacting.In the case of the hydrosilylphosphines R2(H)SiPEt2, the kétoalkoxymetal derivative cyclises by intramolecular addition SiH/C=O with formation of 2‐sila‐1,3‐dioxepane with a phosphorated substituent: magnified imageThe same acyl‐oxygen cleavage is observed in the action of the metal‐IVb phosphines on succinic anhydride to lead to the kétoesters R3MOCO (CH2)2COPEt2 (M = Si, Ge, Sn). The action of the hydro‐germyl‐ or ‐silyl‐phosphines R2(H)MPEt2 leads, in a first phase, to the corresponding γ‐kétoesters R2(H)MOCOCH2CH2COPEt2 which cyclise via intramolecular addition with formation of cyclic germa‐ or sila‐alkoxy esters. magnified image
Chemistry of sulfines. XII: Cyclo‐addition reactions with dienes
Authors: Zwanenburg B. , Thijs L. , Broens J. B. , Strating J. 
Published: September 2010

AbstractThe cyclo‐addition reaction of sulfines with 1,3‐dienes is described. In all cases studied six‐membered ring sulfoxides were formed (Schemes I, II and III). Sulfines with electron‐withdrawing substituents, such as dichlorosulfine, appeared to be very reactive dienophiles. The stereochemistry of the reaction was studied with Z‐ and E‐chloro‐phenylsulfine and 2,3‐dimethyl‐1,3‐butadiene. The results show that the stereochemical configuration of the starting sulfine is predominantly retained in the (2 + 4) cyclo‐adduct.
Pyrazoles and imidazoles as ligands. Part XII: Metal (II) perchlorates and tetrafluoroborates containing 2‐methylimidazole as ligand
Authors: Reedijk J. 
Published: September 2010

AbstractSeveral complexes of general formula M(2MIz)n(anion)2, with M = Mn, Fe, Co, Ni, Cu, Zn and Cd are reported. The anions are ClO−4 and BF−4, n = 4 or 6, and 2MIz stands for 2‐methylimidazole.The compounds are prepared from alcoholic solutions of the ligand and the metal salt in the presence of triethyl orthoformate.Structural conclusions are drawn from infrared spectra, ligand‐field spectra, X‐ray powder diagrams and paramagnetic resonance measurements.Depending upon the particular cation, the metal ions were found to be tetragonally (Mn, Fe, Cd), tetrahedrally (Co, Zn), square planar (Cu, Ni), or octahedrally (Cd) coordinated. In the tetragonal compounds the ClO−4 and BF−4 anions are very weakly coordinated to the metal ions. No anion coordination occurs in the remaining compounds.
Interpretation of E.P.R.‐Spectra of powdered octahedral nickel(II) complexes with nitrogen‐donor ligands
Authors: Reedijk J. , Nieuwenhuijse B. 
Published: September 2010

AbstractCalculation methods for the evaluation of the parameters g, D and E for an S = 1 system, from paramagnetic resonance powder spectra are discussed and applied to a number of compounds having the general formula Ni(ligand)6(anion)2; in this formula the ligands are nitrogen donors such as nitriles, pyrazoles and imidazoles, with large anions like ClO−4, BF−4, SbCl−6, InBr−4 and GaCl−4.A treatment similar to that of organic triplet molecules can be used for the interpretation, despite the fact that the observed bands are rather broad.In the present compounds the g‐values were found to be isotropic within experimental error in the region 2.17‐2.20; the D‐values varied from 0.05‐0.90 cm−1 in the several compounds. The rhombic distortion (usually expressed as λ = E/D) was found to be small for most compounds, although λ‐values of 0.10, 0.16 and 0.33 were also found.
The X‐ray photoelectron spectrum of benzotris [c]‐2‐oxyfurazan (“hexanitrosobenzene”)
Authors: Bus J. 
Published: September 2010

AbstractIn order to confirm the multiple ring structure of benzotris[c]‐2‐oxyfurazan (“hexanitrosobenzene”), the electron‐binding energies of carbon, nitrogen and oxygen in this compound have been measured by X‐ray photoelectron spectroscopy. Charge calculations have been carried out by various methods for the interpretation of the results.For each type of atom the 1s electron energy peak was split into two peaks of approximately equal intensity: carbon, 285.6 and 287.5 eV; nitrogen, 401.3 and 405.0 eV; oxygen, 533.4 and 535.0 eV. The carbon values may be less reliable because of deposition of pump oil onto the sample.These results exclude the hexanitroso structure and support the furazan structure for which further evidence has already been published.
Formation of 2H‐thiopyrans and thiophenes by thermal rearrangement of propargyl vinyl sulfide or its homologues and 2‐alkynyl thienyl sulfides
Authors: Schuijl‐Laros D. , Schuijl P. J. W. , Brandsma L. 
Published: September 2010

Abstract2H‐Thiopyran and a number of derivatives have been obtained in fair to good yields by heating compounds containing the system C ≡ CCSCC, in hexamethylphosphorictriamide. Mixtures of 2H‐thiopyrans and thiophenes are formed when heating is performed in this solvent or in dimethyl sulfoxide in the presence of amines. Thiopyrans, having an alkyl group on ring carbon atom 4, are partly converted into the “exo”‐compounds 4‐alkylidene‐2,3‐dihydro‐4H‐thiopyrans.