bluuebunny/crossref_metadata_2025_split huggingface dataset:
Elaboration of a chiral 20‐crown‐6 from a glucofuranose derivative and its complex formation with alkali cations
Authors: Bakó Peter , Fenichel Laszló , Tōke Laszló , Davison Bruce E. , Patel Alpana 
Published: January 2005

AbstractThe synthesis of bis‐(1,2‐O‐isopropylidene‐6‐O‐triphenylmethyl‐α‐D‐glucofuranosyl)‐20‐crown‐6 (1) and its complexing ability with alkali and ammonium cations are described. The crown ether 1 was synthesized in a stepwise manner via the “half‐crown” (2) using a blocking‐deblocking procedure, in which the 3,3′‐bridge was formed, followed after suitable manipulations, by formation of the 5,5′‐bridge. An unusual feature of the complexing ability of the crown ether is that, although potassium and ammonium ions most closely approach the size of the complexing cavity, it is the sodium ion which forms the most stable complex. Compound 1 does not show chiral recognition toward two alkylammonium salts.
Syntheses and characterization of (N→B)phenyl[N‐arylaminodiacetate‐O,O′,N]boranes and N‐arylaminodiacetic acids
Authors: Mancilla Teresa , de Lourdes Alarcón Ma. , Carrillo Lourdes 
Published: January 2005

AbstractThe (N→B)phenyl[iminodiacetate‐O,O′,N]borane 1 is stable to hydrolysis, and the fact that the N‐H proton has been shown to be more acidic than the α‐protons to the carbonyl groups has led to the syntheses of N‐substituted boron heterocycles. Thus, the reactions of compound 1 with 2,2,6,6‐tetramethylpiperidine and aryl halides led to the syntheses of (N→B)phenyl[N‐arylaminodiacetate‐O,O′,N]boranes 2–9, which were, in turn, hydrolyzed to afford the corresponding N‐arylaminodiacetic acids 10–17. All compounds studied in this work were characterized by 1H, 13C, and 11B (for boron compounds) NMR, infrared, and mass spectroscopy.
1,3,4‐Thia(selena)azaphospholines and phospholidines
Authors: Kamalov R. M. , Stepanov G. S. , Litvinov I. A. , Pudovik M. A. 
Published: January 2005

AbstractO‐Phenyl chloromethyldithio‐ and chloromethylselenothiophosphonic acids, formed by the reaction of O‐phenyl chloromethyl‐(chloro)thiophosphonate with hydrogen sulfide or hydrogen selenide, respectively, in the presence of Et3N, react in situ with alkyl thiocyanates and bis(thiocyanato)methane, yielding 2‐alkylithio‐4,5‐dihydro‐4‐thioxo‐4‐phenoxy‐1,3,4‐thia‐(selena)azaphospholes and 2,4‐dithioxo‐4‐phenoxy‐1,3,4‐thia(selena)azaphospholidines, respectively.
Ab initio study of ion‐molecule reactions between H2SiNH and NH3
Authors: Kawauchi Susumu , Tachibana Akitomo , Yamabe Tokio 
Published: January 2005

AbstractIon‐molecule reaction pathways between H2SiNH and NH3 have been examined by ab initio quantum chemical techniques using polarized split‐valence basis sets and including the effects of electron correlation and zero‐point energy corrections. The proton transfer (PT), hydrogen abstraction (HA), electron transfer (ET), and hydride transfer (HT) processes are thermodynamically unfavorable. The eliminative addition (EA) processes, in spite of their exothermicities, are also unfavorable, because they have activation barriers. The ammonia exchange (AE) process is most likely to occur among the reactions between H2SiNH and NH3 without an activation barrier. Therefore, H2SiNH indicates apparent unreactivity toward NH3. This agrees well with the experimental result reported by Haller that SiH4N+ apparently does not react with NH3.
Regioselectivity of fluoride ion‐induced intramolecular nucleophilic cyclization of heptafluoronaphthyl sulfur diimides 2NfFNSNSiMe3 and 2NfFSNSNS1Me3
Authors: Bagryanskaya Irina Yu. , Gatilov Yuri V. , Miller Alexey O. , Shakirov Makhmut M. , Zibarev Andrey V. 
Published: January 2005

AbstractThe title reaction is highly regioselective, leading in both cases to 4,5,6,7,8,9‐hexafluoronaphtho[1,2‐c]‐[1,2,5]thiadiazole (whose struture is confirmed by X‐ray structure analysis) and 4,5,6,7,8,9‐hexafluoronaphtho[2,3‐c][1,2,5]thiadiazole in ∼94 : 6 ratio. The preferred direction of cyclization is consistent with final product thermodynamics as well as factors of kinetic control for orbital‐controlled reactions (calculated by use of frontier MOs theory).
Synthesis and structure of bis(dialkylamino)carbeniumdithiocarboxylates
Authors: Nagasawa Akira , Akiyama Isao , Mashima Shigeru , Nakayama Juzo 
Published: January 2005

Abstract2‐Chloro and 2‐phenoxy substituted 1,1‐bis(diethylamino)ethylenes (4a and 4c) react with elemental sulfur at room temperature to give the inner salt, bis(diethylamino)carbeniumdithiocarboxylate (1a), in excellent yields with extrusion of hydrogen chloride and phenol, respectively, thus providing a new and convenient synthesis of the structurally interesting inner salt. X‐ray single crystal structure analysis of 1a reveals that the NCN and SCS planes are nearly vertical to each other with a dihedral angle of 82.0° and that the positive and negative charges are delocalized over the NCN and SCS moieties, respectively. Results of solid‐state 13C NMR of 1a are also briefly described.
1,2‐Bis(o‐aminophenoxy)ethane‐N, N, N′, N′‐tetra‐acetic acid derivatives on complexation with lanthanoid metal ions. Correlation between size of trapping hole and metal ion
Authors: Kimura Takahide , Ando Takashi , Maruyama Tetsushi , Sugiyama Takashi , Ohno Atsuyoshi , Okamura Mutsuo 
Published: January 2005

AbstractComplexation of lanthanoid metal ions with 1,2‐bis(o‐aminophenoxy)‐ethane‐N,N,N′,N′‐tetraacetic acid and its two derivatives, in which the distance between the chelating functions is changed, has been studied by potentiometric pH titration. There are two complexation modes depending on the size of the metal ion. Structural flexibility of the chelator accounts for the change in the complexation mode.
Some reactions with ω‐bromoacetophenone: Synthesis of Δαβ‐butenolide and its transformation into pyrrole derivatives
Authors: Abdelrazek Fathy M. , Kandeel Zaghloul E. , Salah Abdellatif M. 
Published: January 2005

Abstractω‐Bromoacetophenone reacts with the sodium salt of ethyl cyanoacetate to afford α‐cyano‐β‐phenyl‐Δαβ‐butenolide. This butenolide undergoes azo coupling with diazotized aromatic amines (ArNH2) to afford the hydrazo derivatives. These hydrazo derivatives (ArPh, 4‐ClC6H4, 4‐MeC6H4, 4‐MeOC6H4) were transformed into the corresponding 3(2H)‐pyridazinone derivatives on stirring in methanol in the presence of potassium hydroxide. These latter compounds were converted into the corresponding 3‐cyano‐2,5‐dihydroxy‐4‐phenyl‐N‐arylpyrrole derivatives on reduction with zinc dust in refluxing acetic acid, presumably via reductive cleavage of the NN bond of the pyridazine followed by recyclization via loss of ammonia.
Synthesis, structure, and oxidation of 3,4‐dihydro‐1,2,5‐benzotrithiepins
Authors: Ogawa Satoshi , Sasaki Masaki , Ogasawara Takayuki , Sato Ryu , Kawai Yasushi 
Published: January 2005

AbstractStable benzene‐fused polysulfide compounds, 3,4‐dihydro‐1,2,5‐benzotrithiepins (1a‐c), have been prepared, and the structure of 1a has been determined by X‐ray crystallographic analysis. While the electrophilic oxidation of compounds 1 with m‐chloroperbenzoic acid gave the corresponding 3,4‐dihydro‐1,2,5‐benzotrithiepin 5‐oxides (2) in moderate yields, the oxidation of 1 with N‐bromosuccinimide afforded a mixture of 5‐oxides 2, unexpected, inseparable 3,4‐dihydro‐1,2,5‐benzotrithiepin 2,2‐dioxides (3), and 3,4‐dihydro‐1,2,5‐benzotrithiepin 1,1‐dioxides (4). Semiempirical PM3 calculations were carried out, and the computed HOMO of 1a suggested a significant favoring of electrophilic reactions at the sulfur atom at the 5‐position. The treatment of 5‐oxides 2 with acetyl bromide or oxalyl dibromide as halogenating reagents gave 2,2‐dioxides 3 and 1,1‐dioxides 4, suggesting that an intramolecular halogen transfer from the 5‐position (sulfide moiety) to the 1‐ and 2‐positions (disulfide moiety) took place in the reactions.
Electron distribution in 1‐organo‐1H‐tetrazole‐5‐thiols. Crystal and molecular structure of 1‐methyl‐1H‐tetrazole‐5‐thiol and its potassium (18‐crown‐6) salt
Authors: Cea‐Olivares Raymundo , Jiménez‐Sandoval Omar , Hernández‐Ortega Simón , Sánchez Mónica , Toscano Rubŕn Alfredo , Haiduc Ionel 
Published: January 2005

AbstractThe crystal and molecular structures of both neutral and anionic 1‐methyl‐1H‐tetrazole‐5‐thiol, as its potassium(18‐crown‐6) salt, are reported. In the solid state, the molecular thiotetrazole adopts a planar, dimeric arrangement, in which two neighboring molecules are hydrogen bridged. Each monomeric unit exhibits considerable π electron delocalization over the CN2S fragment. The anionic form displays extensive, but not uniform, π electron delocalization within the ring, which also extends to the exocyclic carbon–sulfur bond, the structure being best described as a hybrid. The potassium cation is coordinated to the macrocyclic 18‐crown‐6 ether as expected, but it also interacts with the NCS fragment of the tetrazolethiolate ring.
Synthesis and antimalarial activities of structurally simplified 1,2,4‐trioxanes related to artemisinin
Authors: Posner Gary H. , Oh Chang H. , Gerena Lucia , Milhous Wilbur K. 
Published: January 2005

AbstractEleven derivatives of the clinically useful, antimalarial, 1,2,4‐trioxane artemisinin have been synthesized in only several steps from commercial cyclohexanones. Of these simple, tricyclic 1,2,4‐trioxanes, 10 showed considerable in vitro antimalarial activity, with one being as potent as artemisinin. Some structure‐activity relationship generalizations are made from this series of artemisinin analogs. Triethylsilyl hydrotrioxide (Et3SiOOOH), prepared in situ from ozone and triethylsilane, is shown to be a mild, fastacting, and effective dioxetane‐forming reagent with vinyl ethers and with a vinyl thioether on relatively small (50–100 mg) scale.
Selective reductions. 56. Exploration of the B‐haloisopinocampheylboranes for asymmetric reduction of ketones
Authors: Brown Herbert C. , Ramachandran P. Veeraraghavan , Chandrasekharan J. 
Published: January 2005

AbstractA series of diisopinocampheylhaloboranes and monoisopinocampheyldihaloboranes were synthesized by the reaction of the corresponding boranes with the respective HX or X2 (X = halogen) or by the hydroboration of α‐pinene with the corresponding haloboranes. Stabilities of these haloboranes in various solvents were studied. Most of these haloboranes proved capable of reducing prochiral ketones to the alcohols with significant optical induction. When tested against a representative aromatic and aliphatic prochiral ketone, acetophenone and 3‐methyl‐2‐butanone, respectively, α‐phenethyl alcohol in 65–98% ee and 3‐methyl‐2‐butanol in 28–59% ee were obtained. Some of them exhibited anomalous behavior.
Rearrangement of 6,7‐dithiabicyclo[3.1.1]heptane 6‐oxides to a 7,8‐dithia‐6‐oxabicyclo[3.2.1]octane catalyzed by montmorillonite K 10
Authors: Ishii Akihiko , Jin Yi‐Nan , Hoshino Masamatsu , Nakayama Juzo 
Published: January 2005

AbstractTreatment of 2,2,4,4‐tetramethyl‐1,5‐diphenyl‐6,7‐dithiabicyclo[3.1.1]heptane 6‐endo‐oxide (2) with Montmorillonitc K 10 in dichloromethane gave 2,2,‐4,4‐tetramethyl‐1,5‐diphenyl‐7,8‐dithia‐6‐oxabicyclo‐[3.2.1]octane (6) (11%) with recovery of 2 (87%). Under similar reaction conditions, the 6‐exo‐oxide 7 and the sulfenate 6 gave a mixture of 6 (21%), 2 (67%), and 7 (9%) and a mixture of 2 (89%) and 6 (9%), respectively. These results indicate the relative thermodynamic stabilities of the three compounds to be 2 > 6 > 7. PM3 calculations on these compounds showed the heats of formation (kcal/mol) to be in the following order: 6 (44.12783), 2 (57.46721), and 7 (59.37918). The driving force of this unusual 1,2‐rearrangement of 2 and 7 to 6 would be the release of the ring strain of the bicyclo[3.1.1]heptane system of 2 and 7 by ring expansion.
Synthesis of chromophoric bisazocrowndilactams
Authors: Ibrahim Yehia A. , Elwahy Ahmed H. M. , El‐Kareish Gamal M. M. 
Published: January 2005

AbstractThe coupling of 1,2‐bis(o‐hydroxybenzamido)ethane 1 with two equivalents of the appropriate arenediazonium chloride in aqueous sodium hydroxide afforded the corresponding 1,2‐bis(2‐hydroxy‐5‐arylazobenzoylamino)ethanes 4–6. The latter were converted to the corresponding dipotassium salts 7–9, which were reacted with the appropriate dihalo compound or ditosylate in boiling DMF to give the corresponding 14‐17‐membered macrocyclic bis‐azo‐crowndilactams 10–18 in 58–65% yields. Compound 14 was N‐alkylated to give the corresponding N,N′‐dibenzyl derivative 19.
Construction of α‐phosphonolactams via rhodium (II)‐catalyzed intramolecular CH insertion reactions
Authors: Okada Yoshiharu , Minami Toru , Miyamoto Masahiro , Otaguro Tsuneyuki , Sawasaki Sumiko , Ichikawa Junji 
Published: January 2005

AbstractThe Rh(II)‐catalyzed intramolecular CH insertion reactions of N,N‐dialkyl‐α‐diazo‐α‐(diethylphosphono)acetamides 2a,f–j in CHCl3 or ClCH2CH2Cl were found to give monocyclic and bicyclic α‐phosphono‐β‐lactams, 3a and 3f–j, in 43–67% yields via regiospecific α‐CH insertion of the N‐alkyl groups. Similar treatment of N‐benzyl‐N‐isopropyl‐α‐diazo‐α‐(diethylphosphono)acetamide (2b) and the corresponding N‐isobutyl‐N‐methylacetamide 2d in ClCH2CH2Cl afforded mixtures of β‐lactams 3b (35%) and and 3b′ (16%), β‐lactam 3d (47%), and γ‐lactam 4d (10%), respectively, each of which is formed by the competitive CH insertion reaction between benzylic and isopropyl α‐CH bonds and between methyl α‐CH and methine β‐CH bonds, respectively. For the formation of β‐lactams, the selectivity in the rhodium‐mediated CH insertion in ClCH2CH2Cl follows the order methyl > methine > benzylic α‐CH bond on N‐substituents. The N,N‐dibutyl‐α‐diazo homologue 2c and Nα[α‐diazo‐α‐(diethylphosphono)acetyl]‐2‐methylindoline (2k) exclusively produced γ‐lactams 4c (67%) and 4k (81%) via insertion into the methylene β‐CH and methyl β‐CH bonds. tert‐Butyl N‐[α‐diazo‐α‐(dibenzylphosphono)acetyl]‐piperidine‐2‐carboxylate (2m) on similar treatment, followed by deprotection of the benzyl ester afforded the 7‐phosphono carbacepham 6 in 32% overall yield. Similar Rh(II)‐catalyzed cyclization of N‐methyl‐N[4‐benzyloxy‐α‐(diethylphosphono)‐phenyl(diethyl‐phosphono)methyl]‐α‐diazo‐acetamide (2n) led to 1‐[4′‐benzylphenyl(diethylphosphono)methyl] ‐3‐(diethyl‐phosphono)azetidin‐2‐one (3n) in 78% yicld. The phosphono group at C‐7 of 3f was converted into the acetylamino group via a four‐step reaction. Application of chiral rhodium(II) carboxylates 12a–c to the insertion reactions of 2b,c produced α‐phosphono‐β‐and γ‐lactams, 3b and 4c, in 6–24% ee and 25–29% ee, respectively.
Dediazoniation of arenediazonium salts with trivalent‐phosphorus compounds. Tool for examination of the reactivity of phosphorus‐centered radicals
Authors: Yasui Shinro , Shioji Kosei , Ohno Atsuyoshi 
Published: January 2005

AbstractTrialkyl phosphites (1), dialkyl phenylphosphinites (2), and alkyl diphenylphosphonites (3) as well as 2‐phenyl‐1,3,2‐dioxaphospholan (4b) and 2‐phenyl‐1,3,2‐dioxaphosphorinan (4b) give rise to dediazoniation of arenediazonium salt (5) in an alcoholic solvent under an argon atmosphere at 20°C. The reaction proceeds via a radical‐chain mechanism initiated by single‐electron transfer (SET) from the trivalent‐phosphorus compounds to 5, as a result of which, an aryl radical Ar⋅ and a cation radical 15 are generated from the former and the latter, respectively. The aryl radical Ar⋅ participates in this chain process abstracting a hydrogen from the solvent alcohol, yielding the corresponding arene ArH. The cation radical 15 undergoes both an ionic reaction with the solvent alcohol and a radical coupling with Ar⋅, giving the phosphoranyl radical 16 and the phosphonium ion 17, respectively, as intermediates. The phosphoranyl intermediate 16 decomposes through either the SET process to 5 or by β‐scission, yielding the oxidation product (phosphate, phosphonate, or phosphinate from 1, 2, or 3, respectively, or phosphonates from 4). The phosphonium intermediate 17 affords the arylated product (phosphonate, phosphinate, or phosphine oxide from 1, 2, 3, respectively, or the phosphinate from 4). Among the trivalent‐phosphorus compounds tested, 1 gives the arylated product in the highest yield. This observation, together with the literature data of ESR for structurally related phosphoranyl radicals, indicates that the radical coupling of 15 with Ar⋅ is facilitated by the high spin density on its central phosphorus atom.
The reaction of stable phosphorus ylides with elemental sulfur. Formation of olefins; cis‐trans selectivity
Authors: Okuma Kentaro , Ishida Tomoko , Morita Shinya , Ohta Hiroshi , Inoue Tohru 
Published: January 2005

AbstractMetal and temperature effects on thio‐Wittig reactions have been studied. Stabilized phosphorus ylides, such as carbomethoxymethylenetriphenylphosphorane, reacted with sulfur to afford dimethyl maleate and dimethyl fumarate in a 1:4 ratio. As in the case of conventional Wittig reactions with semistabilized ylides, it has been shown that the stereochemistry (E:Z ratio) of alkene formation is determined at the point that a new carbon–carbon bond has been formed to give a thiaphosphetane intermediate. The temperature dependence of this reaction is also discussed.
A new synthetic route to fluorine‐containing thiochromones
Authors: Huang Wei‐Yuan , Liu Yan‐Song 
Published: January 2005

AbstractThe Michael‐addition of polyfluoroalkenoates with thiophenols in acetonitrile in the presence of Na‐HCO3 yielded the corresponding addition products, which were further treated with polyphosphoric acid (PPA) to give a series of new fluorine‐containing thiochromones in good yields.
Crystal and molecular structures of diastereomeric 2‐phosphoryl‐, 2‐thiophosphoryl‐, and 2‐selenophosphoryl‐substituted 1,3‐dithianes
Authors: Wieczorek Michał W. , Bujacz Grzegorz D. , Majzner Wiesław R. , Graczyk Piotr P. , Mikołajczyk Marian 
Published: January 2005

AbstractThe crystal and molecular structures of five pairs of diastereomeric cis‐ and trans‐2‐phosphoryl‐, 2‐thiophosphoryl‐, and 2‐selenophosphoryl‐5‐t‐butyl‐1,3‐dithianes have been determined.For all the examined compounds, all of the basic geometrical parameters, such as bond lengths, bond and torsion angles, and the deformation of a chair conformation of the six‐membered heterocyclic rings, have been established. The differences in corresponding bond lengths and valence angles in diastereomeric cis‐ and trans‐2‐P‐substituted 1,3‐dithianes are discussed.
Dense energetic compounds of carbon, hydrogen, nitrogen, and oxygen atoms. V. 1,2,7,8‐bisfuroxano‐3,4,9,10‐tetranitro‐5, 11‐dehydro‐5H, 11H‐benzotriazolo[2, 1‐a]benzotriazole (BTBB)
Authors: Subramanian Ganesan , Trudell Mark L. , Boyer Joseph H. 
Published: January 2005

AbstractA reaction between 2, 8‐dichloro‐4, 10‐dinitro‐5, 11‐dehydro‐5H, 11H‐benzotriazolo[2, 1‐a]‐benzotriazole 8 and sodium azide in dimethyl sulfoxide produced 3, 9‐diazido‐4, 10‐dinitro‐5, 11‐dehydro‐5H, 11H‐benzotriazolo [2, 1‐a]benzotriazole 10 rather than the 2.8‐diazido isomer 9 expected by direct displacement. Thermolytic elimination of nitrogen (2 moles) converted the dinitro diazide 10 to 3,4,9,10‐bisfuroxano‐5, 11‐dehydro‐5H, 11H‐benzotriazolo[2, 1‐a]benzotriazole 11 that was subsequently nitrated to give the 2,8‐dinitro derivative 12. Similar nitration converted the dinitro diazide 9 to the trinitro 15 and tetranitro 14 derivatives: thermolysis of the latter gave 1,2,7,8‐bisfuroxano‐4, 10‐dinitro‐5, 11‐dehydro‐5H, 11H‐benzotriazolo[2, 1‐a]‐benzotriazole 16. Nitration (100% HNO3, CF3SO3H) converted compound 16 to the 3,4,10‐trinitro derivative 17, whereas a similar nitration (100% HNO3, FSO3H) gave the title compound BTBB, an insensitive high‐energy, high‐density (d 2.03 g/cc) molecule. © 1995 John Wiley & Sons, Inc.
Phosphorylation of five‐membered aromatic heterocycles with phosphorus tribromide
Authors: Tolmachev Andrew A. , Ivonin Sergey P. , Pinchuk Alexander M. 
Published: January 2005

AbstractPhosphorus trichloride in a basic medium is a convenient reagent for the direct C‐phosphorylation of electron‐rich aromatic heterocycles. The compounds obtained can be used for the synthesis of various types of heteroaryl and diheteroaryl derivatives of tri‐ and pentavalent phosphorus. © 1995 John Wiley & Sons, Inc.
The isomerization/chlorination of 0,0‐dialkyl methylthiophosphonates with phosphorus oxychloride—a new convenient synthesis of S‐alkyl methylthiophosphonic acid derivatives
Authors: Tang Chu Chi , Ma Fu Peng , Zhang Kun , He Zheng Jie , Jin Yao Chun 
Published: January 2005

AbstractA new method for the synthesis of S‐alkyl methylthiophosphonic acid derivatives is reported. The chlorination of 0,0‐dialkyl methylthiophosphonates 8 with phosphorus oxychloride proceeds with isomerization of the P=S to the P–S bond to give S‐alkyl methylthiophosphonochloridates 9, which react further with various nucleophiles in the presence of triethylamine to afford S‐alkyl methylthiophosphonic acid derivatives 10. Among them, several compounds 10 show excellent fungicidal or insecticidal activities. © 1995 John Wiley & Sons, Inc.
Reaction of diphenylphosphine oxide with a 10‐methylacridinium salt. Reversible formation of a PC covalent bond
Authors: Yasui Shinro , Shioji Kosei , Ohno Atsuyoshi , Yoshihara Masakuni 
Published: January 2005

AbstractDiphenylphosphine oxide (1′) reacts reversibly with a 10‐methylacridinium salt (2) in acetonitrile at 20°C to equilibrate with a new salt 3 formed by the addition of 1′ to the cation of 2. The forward reaction in this equilibrium proceeds via nucleophilic attack by the phosphorus atom of diphenylphosphinous acid (1), the trivalent tautomer of 1′, upon the 9‐carbon atom of the cation of 2, forming a phosphorus–carbon covalent bond. The equilibrium constant has been determined by UV‐vis and 1H NMR spectroscopy as well as by HPLC analysis. The reaction has been analyzed kinetically, and the results have been compared with those obtained in the similar reaction of an alkyl ester of 1, the diphenylphosphinite (5), with 2 that gives the phosphonium salt 6. It is suggested that 6 is much more stable than 3.The equilibrium constant for the tautomerism between 1′ and 1 has also been estimated. © 1995 John Wiley & Sons, Inc.
First synthesis and structural determination of 1, 1′‐spirobis(3H‐2, 1‐benzoxatellurole)‐3, 3′‐dione ([10‐Te‐4(C202)])
Authors: Takaguchi Yutaka , Furukawa Naomichi 
Published: January 2005

Abstract1, 1′‐Spirobis(3H‐2, 1‐benzoxatellurole) ‐3, 3′‐dione [10‐Te‐4(C202)] (1c) with five‐membered spirorings was prepared, and its molecular structure was determined by X‐ray crystallographic analysis. The two types of arrangement of the ligands about the central tellurium atom show considerably distorted trigonal bipyramidal (TBP) geometries. The tellurane 1c undergoes a ring‐opening reaction on treatment with aqueous sodium hydroxide to afford the telluroxide 10, which reacts with aqueous hydrochloric acid at room temperature to give again the tellurane 1c in quantitative yield. © 1995 John Wiley & Sons, Inc.
Synthesis and spectral analysis of 8‐substituted dinaphtho [2,1‐d:1′,2′‐g] [1,3,6,2]dioxathiaphosphocin 8‐oxides
Authors: Reddy B. Sankara , Anuradha K. , Reddy C. Devendranath , Kumar N. Jagadeesh , Krishnaiah M. , Berlin K. Darrell 
Published: January 2005

AbstractSynthesis and spectral analysis of several 8‐substituted dinaphtho[2,1‐d:1′,2′‐g][1,3,6,2]dioxathiaphosphocin 8‐oxides have been described. An X‐ray crystallographic study of 8‐(2′,3′‐ dimethylphenoxy)dinaphtho[2,1 ‐ d:1′,2′‐g][1,3,6,2]dioxathiaphosphocin 8‐oxide has indicated that, in the solid state, the dioxathiaphosphocin ring is in a distorted‐boat–like conformation with the P = O group and bridged S atom directed away from each other. Electron impact mass spectra showed M+ and (M–OR)+ ions, containing the dioxathiaphosphocin ring system, confirming the structures of the esters. © 1995 John Wiley & Sons, Inc.