bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural studies of tris(dialkylamino) sulfonium (TAS) fluorosilicates
Authors: Dixon David A. , Farnham William B. , Heilemann W. , Mews R. , Noltemeyer M.
Published: January 2005

The crystal structures of two pentavalent silicon anions are discussed. The structure of [SiMe3F2]− 1 shows a trigonal bipyramidal structure with the fluorines in apical positions. The SiF bond distances are the longest known of this type. The crystal structure of fluorosilicate 2 (1,1‐diphenyl‐1‐fluoro‐3,3‐bis[trifluoromethyl]‐1,3‐dihydro‐2,1‐benzoxasilole[ion 1‐]) is distorted toward a rectangular structure along the Berry pseudorotation coordinate. The lone SiF bond distance in 2 is much shorter than that in 1. The ab initio calculations on a variety of pentavalent fluorinated silicon anions are reported, and good agreement with the experimental data are found. Fluoride affinities for the fluorosilanes are reported and are in reasonable agreement with the experimental values where known. The fluoride affinity of the tetra‐coordinated species is related to the length of the SiF bond in the pentavalent anion.
The photochemical properties of the mono‐and dithioimide derivatives of (E,E)‐dibenzylidene‐N‐phenylsuccinimide
Authors: Davidse P. Adriaan , Dillen Jan L. M.
Published: January 2005

Novel (E,E)‐dibenzylidene‐N‐phenyl succinimide thioimide 1b and dithioimide 1c derivatives of the photochromic fulgimide 1a were synthesized. The thioimide 1b and dithioimide 1c derivatives were found to undergo isomerization as the main photoreaction when irradiated in a variety of organic solvents, as opposed to the reversible electrocyclic ring closure/opening reactions in the case of the fulgimide 1a. The X‐ray crystal structures of 1b and 1c were determined, and the influence of the thiocarbonyl groups on the structural parameters were investigated in comparison to the crystal structure of 1a. The 1H and 13C NMR spectra were recorded for all three compounds 1a, 1b, and 1c and are discussed in terms of their structural and electronic variations, as is the effect on the photochemical behavior. The twisting of the N‐phenyl ring was found to be a consequence of intramolecular steric interactions and not of intermolecular packing forces. This was substantiated by a series of semiempirical (AMI) calculations. The C(thiocarbonyl) was found to be highly deshielded compared to the corresponding C(carbonyl) carbon atom, and the deshielding effect of the thiocarbonyl group was evident throughout the whole thiocinnamic moiety. Crystal data for monothioimide 1b: spacegroup P21/c with a = 8.794(2) Å, b = 9.623(1) Å, c = 22.182(5) Å, β = 91.45(2)°, Rw = 0.038, and R = 0.067. Dithioimide 1c: spacegroup Pnna with a = 9.411(2) Å, b = 17.304(2) Å, c = 13.574(2) Å, Rw = 0.055, and R = 0.077.
1,3‐Phosphorotropic rearrangement of pyridyl phosphates to hydroxypyridyl phosphonates
Authors: Onys'ko Peter P. , Suvalova Elena A. , Chudakova Tatiana I. , Sinitsa Anatolii D.
Published: January 2005

The lithium diisopropylamide (LDA) induced regioselective 1,3‐rearrangement of 3‐ and 2‐ pyridyl phosphates into the corresponding 3‐hydroxy‐4‐pyridyl‐and 2‐hydroxy‐3‐pyridylphosphonates has been observed and investigated. The rearrangement is proposed as a useful method for a directed introduction of a phosphoryl group into a hydroxypyridine nucleus.
Facile methods of the synthesis of S‐trialkylstannyl esters of dithio‐ and tetrathiophosphoric acids
Authors: Nizamov Il'yas S. , Kuznetzov Vladislav A. , Batyeva Elvira S. , Al'fonsov Vladimir A. , Pudovik Arkady N.
Published: January 2005

S‐Trialkylstannyl dialkyldithiophosphates 3 and tetrathiophosphates 6 were easily obtained in the reaction of tetraphosphorus decasulfide 1 with trialkylalkoxystannanes 2 or alkylthiostannanes 5 under mild conditions. Tetraphosphorus decasulfide 1 and hexaalkyl distannylsulfides 4 produce tris(trialkylstannyl) tetrathiophosphates 9.
Benzodiselenagermoles and spirobisbenzodiselenagermoles
Authors: Tavarès Pascale , Meunier Philippe , Kubicki Marek M. , Gautheron Bernard , Dousse Gabriel , Lavayssière Hélène , Satgé Jacques
Published: January 2005

Synthesis of benzodiselenagermoles and bisbenzodiselenagermoles was carried out by transmetallation group 4 → group 14 between diselenophenylenezirconocenes and dialkyl‐, diaryl‐ or alkylaryldichlorogermanes, aryltrichlorogermane or germanium tetrachloride. The new compounds were studied by1H,77Se NMR and mass spectrometry. In the case of compounds with substituted phenyl groups, double irradiation and 2D NMR experiments were performed to determine the chemical shifts of the two selenium atoms. The crystal structure of a spirobisbenzodiselenagermole has been established by X‐ray diffraction analysis.
Phosphoryl transfer reaction of phospho‐histidine
Authors: Li Yuan‐Chao , Tan Bo , Zhao Yu‐Fen
Published: January 2005

N‐phosphorylhistidine was converted into its ester and phosphoric ester exchanged products in alcoholic media. It was demonstrated that the co‐participation of the three functional groups of phosphoryl, imidazolyl, and carboxyl in the molecule is essential for these reactions to occur. Also, the neat phosphoryl transfer reaction occurs with Nα, NIm‐Bis‐phosphohistidine.
Oxidation of congested thiophene 1,1‐dioxides with m‐chloroperbenzoic acid. Formation of epoxides and thiete 1,1‐dioxides and steric acceleration
Authors: Kamiyama Hiroaki , Hasemi Ryuji , Nakayama Juzo
Published: January 2005

A series of thiophene dioxides (3), including highly congested ones, were synthesized. Their oxidation with m‐chloroperbenzoic acid (m‐CPBA) was investigated either in the presence or in the absence of Na2CO3. The following conclusions were reached. (1) Oxidation in the presence of Na2CO3 affords the corresponding epoxides (4) in moderate to excellent yields. (2) Oxidation in the absence of Na2CO3 produces the ring‐contracted thiete 1,1‐dioxides (5) as the principal product, thus providing a novel synthesis of the sulfur‐containing unsaturated four‐membered ring system. If necessary, 5 can also be derived by treatment of 4 with BF3·Et2O. In an extreme case, the oxidation of 3,4‐di(1‐adamantyl)thiophene afforded the corresponding thiete dioxide 5b directly in 78% yield. (3) Oxidation takes place faster with a more congested 3, probably because of destabilization of the HOMO by steric repulsion between bulky substituents and also owing to relief of steric crowding on going from the ground to the transition state. (4) The formation of 5 from 3 in the absence of Na2CO3 can be explained by the occurrence of an acid‐catalyzed rearrangement of 4 initially formed. However, a competitive pathway leading directly to 5 may also be operative.
New functionalization at the 5‐position of uracils by selenenylation
Authors: Kim Yong Hae , Lee Chun Ho , Lee Dong Hoon
Published: January 2005

Electrophilic substitution of phenylselenenyl chloride at the 5‐position of uracils in the presence of silver reagents, such as Ag2O, AgBF4, or CF3CO2Ag, afforded the corresponding 5‐phenylselenenyluracils in excellent yields. 1,3‐Dimethyl‐5‐phenylselenenyluracil(2a), 5‐phenylselenenyl‐(2′,3′,5′‐tri‐O‐acetyl)uridine(2b), 5‐phenylselenoxyl‐1,3‐dimethyluracil(3a) and 5‐phenylselenoxyl‐(2′,3′,5′‐tri‐O‐acetyl)uridine(3b) were used for various transformations at C‐5 or C‐6 of pyrimidine bases via nucleophilic substitution, a free radical process, and a Michael‐type addition utilizing the unique properties of organo‐seleno groups located on C‐5 of pyrimidine bases.
Synthesis and reactions of optically pure cyclohexyl(o‐methoxyphenyl)phosphine‐borane and t‐butyl‐(o‐methoxyphenyl)phosphine‐borane
Authors: Imamoto Tsuneo , Matsuo Masatoshi , Nonomura Taro , Kishikawa Kuniyuki , Yanagawa Masao
Published: January 2005

Cyclohexyl(o‐methoxyphenyl)menthyloxyphosphineborane and t‐butyl(o‐methoxyphenyl)menthyloxyphosphine‐borane were prepared from dichlorocyclohexylphosphine and t‐butyldichlorophosphine by successive treatments with (−)‐menthol, o‐methoxyphenylmagnesium bromide, and borane‐THF complex. The separated pure diastereomers of each of the compounds underwent reaction with lithium naphthalenide to afford optically pure cyclohexyl(o‐methoxyphenyl)phosphine‐borane and t‐butyl(o‐methoxyphenyl)phosphine‐borane, respectively. These secondary phosphine‐boranes reacted readily with various electrophiles in the presence of bases with virtually net retention of configuration. A new chiral phosphine ligand, (S,S)‐1,2‐bis[cyclohexyl(o‐methoxyphenyl)phosphino]ethane was synthesized via the optically pure phosphine‐boranes.
Dense energetic compounds of C, H, N, and O atoms. III. 5‐[4‐nitro‐(1,2,5)oxadiazolyl]‐5H‐[1,2,3]triazolo[4,5‐c][1,2,5]oxadiazole
Authors: Gunasekaran Ananthakrishnan , Boyer Joseph H.
Published: January 2005

Diazidoazofurazan 8 was obtained from the bis‐diazonium salt of diaminoazofurazan 7 by treatment with sodium azide and underwent thermolysis to 5‐[4‐azido‐(1,2,5)oxadiazolyl]‐5H‐[1,2,3]triazolo[4,5‐c][1,2,5] oxadiazole 5. The corresponding amine 13 was obtained from the azide 5 by reduction with stannous chloride and was oxidized by ammonium persulfate to 5‐[4‐nitro‐(1,2,5)oxadiazolyl]‐5H‐[1,2,3]triazolo[4,5‐c][1,2,5]oxadiazole 1. The azide 5 was converted to a phosphinimine 9 in a reaction with triphenylphosphine.
Homopolyatomic and heteropolyatomic halogen cations
Authors: Tornieporth‐Oetting Inis C. , Klapötke Thomas M.
Published: January 2005

This review is not exhaustive in scope but rather focuses on the most recent years of work in the field of cationic halogens, covering the literature up to mid 1992. This area is still currently developing. The review summarizes structure, preparation, and reactivity of cationic halogens. Modern theoretical aspects (ab initio MO calculations) as well as the energetics (thermodynamics) of these species are also included. In particular, the symmetric and unsymmetric structures of heteropolyatomic cations, the charge delocalization and bond lengths alternation in npπ–npπ species (n < 2), and the dimerization by π*‐π* interactions are discussed.
Generation of methylenephosphine oxides by thermal fragmentation of derivatives of the 2‐phosphabicyclo [2.2.2] octa‐5,7‐diene oxide ring system
Authors: Keglevich György , Újszászy Kálmán , Quin Louis D. , Quin Gyöngyi S.
Published: January 2005

Differential thermal analysis and differential scanning calorimetry showed that the title compounds decomposed at 240–260°C with release of the fragment RP(O) = CH2. Mass spectral studies also showed this to be a fragmentation pathway. The extruded methylenephosphine oxide could be trapped with ethanol, hydroquinone, or by reaction with the surface OH groups of silica gel.
Biimidazol‐2‐yl–BF2 complexes
Authors: Ross Timothy W. , Sathyamoorthi Govindarao , Boyer Joseph H.
Published: January 2005

Nonfluorescent 4,4′,5,5′‐tetramethyl‐ and 4,5,4′,5′‐bistetramethylene biimidazol‐2‐yls 5 and 6 combined with boron trifluoride to give the tetramethyl and bistetramethylenebiimidazol‐2‐yl–BF2 complexes 9 and 10 isolated as strongly fluorescent BF3 salts, λf (dichloromethane): 377 nm Φ 0.93 and 386 nm Φ 0.90. Similarly, fluorescent bibenzimidazol‐2‐yl 7, λf (ethanol), 370 nm Φ 0.14, gave a BF2 complex 11 isolated as a BF3 salt λf (ethanol), 417 nm Φ 0.68.
Reactions of p‐quinone monoimines with lawesson reagent and phosphorus pentasulfide
Authors: Boulos Leila S. , Hennawy Ibtisam T. , Arsanious Mona H. N.
Published: January 2005

2, 4‐Bis‐(4‐methoxyphenyl)‐1, 3, 2, 4‐dithiadiphosphetane‐2, 4‐disulfide [Lawesson reagent (LR)] 1 reacts with p‐quinone monoimine‐2a to give the novel benzo‐1,3,2‐oxathiaphosphol‐5‐(methanesulfonamido)‐2‐(4‐methoxyphenyl)‐2‐sulfide 4. On the other hand, the reaction of 2b and 3 with LR 1 leads to the formation of the benzo‐ and the naphtho‐1,3,2‐dithiaphosphol‐5 ‐(benzenesulfonamido)‐ 2‐ (4‐methoxyphenyl) ‐2‐sulfide 5, 6. Thiation of 2a, 2b, and 3 with P4S10 yields phenoxathiin derivatives 8a, 8b, and 9, respectively. The identity of the new products is established from analytical and spectroscopic evidence.
Reactivity of fused 1,3‐benzothiaphospholes: Formation of pentacoordinated derivatives
Authors: Baccolini Graziano , Orsolan Giorgio , Mezzina Elisabetta , Sgarabotto Paolo , Rizzoli Corrado
Published: January 2005

Fused 1,3‐benzothiaphospholes 2 (cis‐2,6,10‐trimethyl‐[1, 3]benzothiaphospholo[2,3‐b][1, 3]benzothiaphosphole) reacts with H2O2 and S8, giving the corresponding oxide and sulfide, respectively. The reactions of 2 with diethyl azodicarboxylate (DEAD)/catechol or DEAD/o‐aminophenol, o‐azidophenol, and tetrachloro‐o‐benzoquinone (TOB) give the first examples of spiro pentacoordinated phosphorus derivatives of this heterocyclic system. The X‐ray structural analysis of spiro compound 3 showed a trigonal bipyramidal configuration at phosphorus in which the three rings assume axial‐equatorial positions.
Intramolecular ring opening of a 2,3‐epoxy alcohol by a xanthate anionic center; stereospecific preparation of 2‐mercapto‐1,3‐diol units
Authors: Uenishi Jun'ichi , Motoyama Mitsuhiro , Nishiyama Yoshitaka , Hirota Yuichi , Kubo Yuki , Akashi Haruo
Published: January 2005

Stereospecific ring openings of optically active 2,3‐epoxy alcohols were performed by the reaction of 1, 3, 5, and 7 with carbon disulfide and sodium hydride to give the five‐membered xanthates 2, 4, 6, and 8. Both enantiomers of 2‐mercapto‐1,3‐diol triacetates, 11 and 14, were derived from 4 and 6, respectively. The ring opening reaction proceeded at −78°C to −30°C, and the yields were around 80%. However, at a higher temperature between 0°C to room temperature, a complicated reaction took place and led to the formation of two isomers of the cyclic thiol carbonates 15 and 16 from 1 or 5. These processes were also stereospecific, and mechanisms have been proposed. In the case of the 3,4‐epoxy alcohol 20, the epoxide ring opening gave the six‐membered xanthate 21 stereospecifically.
Reactions of dithioxo‐1,3,2λ5,4λ5‐dithiadiphosphetanes with trialkylsilyl and stannyl derivatives
Authors: Nizamov Il'yas S. , Kuznetzov Vladislav A. , Batyeva Elvira S. , Al'fonsov Vladimir A. , Pudovik Arkady N.
Published: January 2005

The reactions of homologues of Davy's reagent 1 and Lawesson's reagent 9 with trimethylalkylthiosilanes 2, trimethylsilyl enol ether 4, trimethyl(diethylamino)silane 7, trialkylalkoxystannanes 14, and trialkylalkylthiostannane 15 were studied. On the basis of these studies, novel advantageous methods of synthesizing S‐trialkylsilyl and stannyl esters of tetrathio‐, trithio‐, and amidotrithiophosphoric acids 3, 5, 6, and 4‐methoxyphenyldithio‐ and trithiophosphonic acids 10–13 were developed
The reaction of sulfur with dilithio compounds. The syntheses and structures of phenanthro [1, 10‐cd]‐1,2‐dithiole and phenanthro[4,5‐cde] [1,2]dithiin
Authors: Ashe Arthur J. , Kampf Jeff W. , Savla Paresh M.
Published: January 2005

The sequential reaction of selected polycyclic aromatic hydrocarbons with butyllithium/TMEDA/hexane and sulfur allows preparation of ring‐fused dithiins, dithioles, and thiophenes. In this manner, phenanthrene has been converted to phenanthro[4,5‐cde][1,2]dithiin and phenanthro[1,10cd]‐1,2‐dithiole. Yellow crystals of the dithiin form in C2/c (#15) space group with Z = 4, a = 13.537(3) Å, b = 8.933(2) Å, c = 9.601(4) Å, and β = 116.19 (2)°; while orange crystals of the dithiole form in P212121 (#19) space group with Z = 4, a = 4.1507(5) Å, b = 14.436(3) Å, and c = 16.972(3) Å. Full structures have been determined for both compounds.
New phenylboronic esters derived from inositol [1]
Authors: Salazar‐Pereda Verónica , Martínez‐Martínez Laura , Flores‐Parra Angelina , de Jesús Rosales‐Hoz María , Ariza‐Castolo Armando , Contreras Rosalinda
Published: January 2005

We have prepared two new tetracyclic phenylboronic esters 4 and 5 derived from myo‐inositol and from 1,2‐O‐isopropylidene‐myo‐inositol, respectively. The structures of these compounds were established from NMR and IR spectra, elemental analyses, and an X‐ray diffraction study in the case of 4. Compound 4 is a tetracyclic derivative of the less stable conformer of inositol (five axial hydroxy groups and one equatorial) with two dioxaboroline rings at opposite faces of the six‐membered ring, one formed between the boron atom and the axial hydroxyl groups at C‐3 and C‐5 and the other between the boron atom and the hydroxyl groups at C‐4 and C‐6, and a dioxaborolidine ring bridging C‐1 and C‐2 at axial and equatorial positions. A similar structure was found for 5 with the difference that bridging C‐1 and C‐2 there is a dioxolane ring. The boron atoms are planar with their attached atoms, stabilized by retrocoordination between the boron and oxygen and carbon atoms, respectively. The two phenyl rings that are in the same face of the molecule are essentially parallel, with a dihedral angle between planes of 28.26 ± 0.79°.
Molecular and electronic structure of bromamines
Authors: Novak Igor
Published: January 2005

Molecular and electronic structures and properties of NH2Br, NHBr2, and NBr3 have been studied using ab initio calculations at the Hartree–Fock (HF) and MP2 levels with the aim of complementing very scarce experimental information available for the title molecules. The properties and molecular structures of bromamines are discussed in relationship to other haloamines (fluor‐ and chloramines).
Generation of germyl, stannyl, and plumbyl anions through nucleophilic cleavage of digermanes, distannanes, and diplumbanes
Authors: Buncel E. , Venkatachalam T. K.
Published: January 2005

Nucleophilic cleavage by potassium t‐butoxide on hexaphenyl digermanes, distannanes, and diplumbanes, in N,N′‐dimethylpropyleneurea (DMPU) solvent, provides a facile method for preparation of triphenyl germyl, stannyl, and plumbyl anions.
Heteroarylthiomethylsilanes. Synthesis and application to heteroarylthiomethylation of carbonyl compounds [1]
Authors: Hojo Makoto , Ishibashi Naruyasu , Hosomi Akira
Published: January 2005

Heteroarylthiomethyltrimethylsilanes bearing a 2‐pyridyl, 2‐imidazolyl, 5‐tetrazolyl, or 2‐pyrimidinyl group, readily prepared by the reaction of heteroarylmercaptans with halomethyltrimethylsilane in the presence of a base, are synthetic equivalents of heteroarylthiomethyl anions, otherwise inaccessible, and are effective reagents for the introduction of a heteroarythiomethyl group at a carbonyl carbon atom in the presence of a catalytic amount of tetrabutylammonium fluoride.
Silyl stabilization of unsymmetrical bisketenes: 3‐(Trimethylsilyl) and 3‐(triisopropylsilyl)‐2‐substituted‐1,3‐butadiene‐1,4‐diones
Authors: Allen Annette D. , Ji Ruizhi , Lai Wing‐Yan , Ma Jihai , Tidwell Thomas T.
Published: January 2005

The bisketenes 2‐phenyl and 2‐methyl‐3‐(trimethylsilyl)‐1,3‐butadiene‐1,4‐dione (8 and 10 ) are calculated on the basis of additivity of substituent effects to be less stable than the 3‐phenyl and 3‐methyl‐4‐(trimethylsilyl)cyclobut‐3‐ene‐1,2‐diones ( 7 and 9 ) by 1.9 and 2.6 kcal/mol, respectively. In agreement with this prediction, 8 and 10 are formed by photolysis of 7 and 9, respectively, and undergo thermal reversion to their precursors at similar rates. The concentration of 8 in thermal equilibrium with 7 in CDCl3, as measured by 1H NMR spectroscopy, varied from 2.8% (161°C) to 0.5% (100.5°C), whereas the amount of 10 present at equilibrium with 9 was distinctly less. These measurements allowed the calculation of values ofΔG° (25°C) = 4.4 kcal/mol, ΔH° = 6.9±(1.3) kcal/mol, and ΔS° = 8.5 (±3.2) cal/deg mol for the conversion of 7 to 8, and the equilibrium concentration of 8 at 25°C was estimated to be 0.06%. The triisopropylsilyl analog 12 of 8 was prepared and at 66°C was 2.6 times more reactive in ring closure to the corresponding cyclobutenone compared to 8. Reactions of 8 and 10 with MeOH in CDCl3 give the isolable monoketenes 3‐phenyl and 3‐methyl‐2‐(trimethylsilyl)‐3‐carbomethoxy‐1‐ene‐1‐one (20,21). Reaction of 20 with excess MeOH or H2O gave the diastereomeric dimethyl 2‐(trimethylsilyl)‐3‐phenylsuccinates (22) or ester‐acids 24, respectively. Reaction of 8 with excess N‐methylaniline gave the diamide 25.
Reactions of the phosphinimine, (Me3Si)2NP  NSiMe3 with some unsaturated bifunctional alcohols, ketones, and amines
Authors: Angelov Christo M. , Cavell Ronald G. , Schmutzler Reinhard
Published: January 2005

Reactions of (Me3Si)2NPNsiMe3 with chloroalkanols, N‐methylpropargylamine, 3‐butyne‐2‐one, sucinimide, and chloroacetic acid were investigated. The first step in the reaction is always an addition of the nucleophilic part of the reagent (OH or NH) to the P‐atom. The second step in the reaction, migration of the proton to phosphorus, depends on the substituents on the phosphorus. Highly electronegative substituents increase the stabilization of the P(III) final product.
Phosphonic systems. Part 15. Addition of diethyl prop‐2‐enylphosphonate to aldehydes: Fragmentation vs. isomerization of kinetic products
Authors: Muller Elmar L. , Modro Tomasz A.
Published: January 2005

Lithiated diethyl prop‐2‐enylphosphonate adds to an aliphatic or an aromatic aldehyde, yielding a diastereomeric mixture of the kinetically controlled α‐adduct. Upon warming, these adducts decompose back to starting materials to give finally the thermodynamically controlled γ‐adducts, or undergo fragmentation to diethyl phosphate and (E) dienes. The distribution of the first product between these two pathways is a function of the aldehyde (aromatic vs. aliphatic) and of steric interactions operating within the two diastereomers of the adduct.
Matrix‐isolation and electronic structure of vinyl‐substituted silylenes and their complexes with bases [1]
Authors: Kira Mitsuo , Maruyama Toyotaro , Sakurai Hideki
Published: January 2005

Vinyl‐substituted silylenes, 2,5‐bis(methylene)‐1‐silacyclopentane‐1,1‐diyl (1) and 2‐methylene‐1‐silacyclopentane‐1,1‐diyl (2), generated photochemically from the corresponding trisilanes in 3‐methylpentane (3‐MP) at 77 K, showed broad bands at 505 and 475 nm, respectively, which were assigned to the n(Si)‐3p(Si) transition. The origin of the red shift in the n(Si)‐3p(Si) transition is ascribed to the significant lowering of the 3p(Si) orbital level caused by the vinyl substitution on the silylene; the relatively high‐lying 3p(Si) orbital can interact more effectively with the antibonding π* orbital than with the bonding π orbital of the vinyl group. The absorption spectra for 1 and 2 in the presence of several bases in 3‐MP glass matrix shifted significantly to blue due to the formation of the corresponding base complexes. Analysis of the spectral change of the silylenes upon complexation with bases was very constructive for the understanding of the structural characteristics of substituted silylenes.
Stereospecific synthesis of 6,7‐dihydro‐5H‐1,2,4‐triazolo[3,4‐b][1,3,4]thiadiazines
Authors: Ibrahim Yehia A. , Elwahy Ahmed H. M. , El‐Fiky Ayman E. M.
Published: January 2005

The reaction of 3‐mercapto‐4‐arylideneamino‐1,2,4‐triazoles 2b‐d, 3a‐d with ethyl bromoacetate and/or phenacyl bromide in hot DMF and triethylamine affords the stereochemically pure 7‐acyl‐6‐aryl‐6,7‐dihydro‐5H‐1,2,4‐triazolo[3,4‐b][1,3,4]thiadiazines 4b‐d, 5a‐d, 6b,d in which the consecutive hydrogen atoms N(5)H‐C(6)H‐C(7)H are cis to each other. This stereochemistry was determined by 1H NMR spectroscopy and confirmed by comparison with the spectrum of 3,6‐diphenyl‐6,7‐dihydro‐5H‐1,2,4‐triazolo[3,4‐b][1,3,4]thiadiazine 10. The latter was prepared by NaBH4 reduction of 3,6‐diphenyl‐5H‐1,2,4‐triazolo[3,4‐b][1,3,4]thiadiazine 9. The reported reactions offer two interesting stereospecific syntheses of the condensed heterocyclic compounds.
Mechanism of the controlled hydrolysis of (NPCl2)2NSOCl: Crystal and molecular structure of [KC12H24O6]+[NHPO2NPCl2NSOCl]−
Authors: Winter Herman , Meetsma Auke , van de Grampel Johan C. , Spek Anthony L.
Published: January 2005

The reaction mechanism of controlled hydrolysis of the inorganic ring system (NPCl2)2NSOCl in the presence of KCl and 18‐crown‐6 has been revised and is explained from steric constraints rather than from electronic considerations. The X‐ray structure of one of the hydrolysis products, [KC12H24O6]+‐[NHPO2NPCl2NSOCl]−, shows a dimeric structure of two centrosymmetrically related formula units kept together by hydrogen bridges and K … O coordination. Crystals are monoclinic, space group C2/c with a = 25.698(5), b = 8.223(2), c = 23.665(4) Å, β = 106.03(1)°, V = 4806(2) Å3, and Z = 8. The final R and Rw values are 0.048 and 0.044, respectively.
Sulfur derivatives of 3‐methyl‐5‐phenyl‐1,2,4,3‐triazaphosphole
Authors: Schmidpeter Alfred , Steinmüller Franz , Karaghiosoff Konstantin
Published: January 2005

The triazaphosphole 1 adds sulfur along with HCl or H2S to yield, respectively, the dihydrotriazaphosphole thiochloride 4 and sesquisulfide 5 (two diastereomers). In pyridine solution, 1 adds sulfur alone to yield the trimer of a triazaphosphole monosulfide 7. Its central cyclotriphosphazane trisulfide ring has a trans structure and a boat conformation.
Laser active cyanopyrromethene–BF2 complexes
Authors: Sathyamoorthi Govindaro , Boyer Joseph H. , Allik Toomas H. , Chandra Suresh
Published: January 2005

Treatment with a mixture of formic and hydrobromic acids converted ethyl 3,4‐diethyl‐5‐methyl‐pyrrole‐2‐carboxylate 7a to 3,3′,4,4′‐tetraethyl‐5,5′‐dimethylpyrromethene hydrobromide 8a presumably via the condensation of α‐unsubstituted and α‐formylpyrrole intermediates 7c and 7e formed in situ. The corresponding 6‐cyanohexaalkylpyrromethane 9a was obtained by the addition of hydrogen cyanide to the pyrromethene 8a and was oxidized with bromine to an unstable pyrromethene 10a, an intermediate converted to 1,2,6,7‐tetraethyl‐3,5‐dimethyl‐8‐cyanopyrromethene–BF2 complex 3, (PMTEDC), λlas (plastic) 613–639 nm, in a reaction with boron trifluoride etherate. Ethyl 3,4,5‐trimethylpyrrole‐2‐carboxylate 7b was similarly converted to 1,2,3,5,6,7‐hexamethyl‐8‐cyanopyrromethene–BF2 complex 4, (PMHMC), λlas (plastic) 615–639 nm. Immediately after formation by a condensation between propionyl chloride and 2,4‐dimethyl‐3‐cyanopyrrole 16, unstable 3,3′,5,5′‐tetramethyl‐6‐ethyl‐4,4′‐dicyanopyrromethene hydrochloride 17 was treated with boron trifluoride etherate to give 1,3,5,7‐tetramethyl ‐2,6‐dicyano‐8‐ethylpyrromethene–BF2 complex 18, λlas (ethanol) 540–565 nm.
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

The 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

The (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

O‐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

Ion‐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

The 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

2‐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

Complexation 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

ω‐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

Stable 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

The 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

Eleven 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

A 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

Treatment 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

The 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

The 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

Trialkyl 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

Metal 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

The 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

The 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

A 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

Phosphorus 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

A 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

Diphenylphosphine 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.