bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of functionalized phosphinines: Aromatization of Diels‐Alder adducts of P‐chlorobis(trimethylsilyl)methylenephosphine
Authors: Abbari Mustapha , Ko Yeung Yat Cheng Yeung Lam , Carriéa Robert 
Published: January 2005

AbstractThe Diels‐Alder adducts of functionalized dienes with P‐chloro‐bis(trimethylsilyl)methylenephosphine can be aromatized, except in a few particular cases, thus opening a general route to functionalized phosphinines. The aromatization procedure differs with the substituents. Intermediates such as secondary cyclic phosphines could be characterized and even isolated. In some cases, aromatization and 1,5 sigmatropic shift of a trimethylsilyl group were observed and hydrogenolysis of the CSi bond as well.
Crystal structure and theoretical investigation of the configurations of 1,3‐dichloro‐1,3‐diazetidine‐2,4‐dione and 1,3‐bis(trimethylsilyl)‐1,3‐diazetidine‐2,4‐dione
Authors: Belaj Ferdinand , Nachbaur Edgar , Faleschini Gottfried , Janoschek Rudolf 
Published: January 2005

AbstractCrystal structures of 1,3‐dichloro‐1,3‐diazetidine‐2,4‐dione (1) and the hitherto unknown compound 1,3‐bis(trimethylsilyl)‐1,3‐diazetidine‐2,4‐dione (2) have been determined by X‐‐ray crystallography: 1: (CINCO)2, Mr = 154.94, T = 295 K, orthorhombic, Pbca, a = 7.699(1), b = 6.706(1), c = 10.598(2) Å, V = 547.2(2) Å3, Z = 4, dx = 1.881 g/cm3, μ = 10.9 cm−1, R = 3.14%, Rw = 2.82% (660 observations, 38 parameters). 2: [(CH3)3SiNCO]2, Mr = 230.41, T = 100 K, monoclinic, I2/a, a = 20.257(2), b = 6.416(1), c = 21.260(3) Å, β = 101.29(1)°, V = 2709.7(6) Å3, Z = 8, dx = 1.130 g/cm3, μ = 2.4 cm−1, R = 4.86%, Rw = 4.39% (2375 observations, 151 parameters). In both compounds, the symmetry of the (XNCO)2 framework (X = Cl, Si) was determined to be nearly C2h with trans configuration of the exocyclic X atoms. Extreme values were observed for the angles between the ring plane and the exocyclic N–X bonds: 32.5(1)° in 1 and 2.5(2)° and 0.8(2)° in 2, respectively. Quantum chemical procedures at various levels of theory (ab initio SCF and semi‐empirical PM3) applied to 1 revealed the possible appearance of two isomers, a lower energy trans form and a higher energy cis form (approx. 2.4 kcal/mol above trans) differing mainly in the spatial arrangement of the chlorine atoms. The calculations excluded a planar heavy‐atom configuration by missing a local energy minimum.
Crystal structure of dicyclohexylammonium succinatotriphenylstannate at 138 K
Authors: Ng Seik Weng , Das V. G. Kumar , Xiao Gaoyi , Helm Dick Van Der , Holec̆ek Jaroslav , Lyc̆ka Antonín 
Published: January 2005

AbstractDicyclohexylammonium succinatotriphenylstannate, synthesized by condensing [(c‐C6H11)2NH2] [HO2C(CH2)2CO2] with (C6H5)3SnOH, has a zig‐zag structure consisting of polymeric chains in which planar triphenyltin cations (Σ C–Sn–C = 360.0(2)°) are axially linked by succinato dianions (Sn–O = 2.214(2) Å; O–Sn–O = 172.52(6)°); the dicyclohexylammonium cations surround the chain and are hydrogen‐bonded to the acyl oxygens of the ligand (N…O = 2.829(3) Å). The stannate is four‐coordinate in CDCl3 solution.
2,4‐Dimethoxycarbonyl‐1,1,3,3‐tetrakis(dimethylamino)‐1λ5,3λ5‐diphosphete
Authors: Fluck Ekkehard , Spahn Manfred , Heckmann Gernot , Borrmann Horst , Obermeyer Axel 
Published: January 2005

Abstract1,1,3,3 ‐ Tetrakis(dimethylamino) ‐ 1λ5,3λ5 ‐ diphosphete, 1, reacts with cyanoformic acid methyl ester to form two isomers of the title compound 2. Properties, NMR, mass, and IR spectra of 2, as well as the molecular and crystal structure of the E isomer of 2, are described and discussed.
Enolization of the phosphoryl group
Authors: Mastryukova Tatjana A. , Kabachnik Martin I. 
Published: January 2005

AbstractEnolization of the phosphoryl group has been studied where Y = PPh3, CN, Ts, COOEt, CONEt2; R and R′ = Et, Bu, Ph, EtO, BuO, PhO; and X = Cl, Br, ClO4, BF4. It has been established that substances with are phosphaenols, but in substances with Y = CONEt2 the phosphoryl group cannot be enolized under any conditions. Phosphaenolization is favored by a high acidifying ability of the Y group, the ability of the X anion to stabilize the phosphaenolic form due to formation of a hydrogen bond OH…X with the anion, and a low electronegativity of R and R′ groups. To evaluate the acidifying ability of Y, this article defines specific σ− constants dependent on the number of substituents at the α‐carbon atom: σCH3−, σCH2− and σCH−. Their sums characterize the enolization ability of the phosphoryl group. The enolic structure in the solid state is possible if ∑CHn− > 2. If this sum lies in the range of 2 < ∑CHn− < 2.6 the phosphoryl–phosphaenol tautomerism can be expected in appropriate solutions. Acidic properties of the investigated compounds in MeNO2 and EtOH (absolute) have been determined. Calculations of the acidity of the phosphoryl CH forms (A) and of the phosphaenol OH forms (B) have been carried out.
Crystal structure and stereochemistry of (PS*, 2S*, 3aS*)‐hexahydro‐2‐(tert‐butylvinylthiophosphinyl)‐6,6‐ dimethylpyrrolo[1,2‐b]isoxazole
Authors: Pietrusiewicz K. Michał , Wieczorek Wanda , Cicchi Stefano , Brandi Alberto 
Published: January 2005

AbstractThe structure of the major product of the cycloaddition of 2,2‐dimethyl‐3,4‐dihydro‐2H‐pyrrole N‐oxide to tert‐butyldivinylphosphine sulfide was analyzed by means of single‐crystal X‐ray diffraction technique. The analysis revealed two crystallographically independent molecules that differed in conformation of the fused five‐membered heterocyclic rings. These rings were found to be two envelopes in one molecule and two half‐chairs in the other. The studied compound was identified as an exo adduct of the expected erythro configuration and was found to favor a conformation in which the PS and ring C–O bonds were anti and the CC–PS moiety was in the s‐cis array. C14H26NOPS, space group P¯1, a = 10.6004(7) Å, b = 12.3225(6) Å, c = 13.4404(7) Å, α = 104.073(4)°, β = 92.758(4)°, γ = 95.968(5)°, V = 1688.802(4) Å3, Z = 4.
Dense compounds of C, H, N, and O atoms: II [1]. Nitramine and nitrosamine derivatives of 2‐oxo‐ and 2‐iminooctahydroimidazo‐[4,5‐d]imidazole
Authors: Ramakrishnan Vayalakkavoor T. , Vedachalam Murugappa , Boyer Joseph H. 
Published: January 2005

AbstractThe 4,6‐dinitroso derivative 11 was obtained (83%) by the nitrosation of 2‐oxooctahydroimidazo[4,5‐d]‐imidazole 1 as the dihydrochloride and was converted to the 4,6‐dinitro derivative 12 [66%] by treatment with nitric acid (100%, ‐40°C) and to the 1,4,6‐trinitro derivative 13 (66%) and the 1,3,4,6‐tetranitro derivative 2 (86%) by treatment with nitric acid (100%) in acetic anhydride at 0–5°C and 10–25°C respectively. Similar treatment with nitric acid (100%) in either acetic or trifluoroacetic anhydride at 0–25°C converted the trinitro compound 13 to the tetranitro compound 2 (86%). The dinitramine 12 was also obtained (43%) from the diamine 1 by nitration with nitric acid (100%, ‐40°C). A reaction between 2‐nitrimino‐5‐iminooctahydroimidazo[4,5‐d]imidazole 7 as a hydrochloride salt (from an acid catalyzed condensation between 4,5‐dihydroxy‐2‐nitriminoimidazolidine 6 and guanidine) and nitric acid (100%, ‐40°C) gave the 2,5‐dinitrimino derivative 14 (85%) isolated as a monohydrate. The nitrate salt 7 · HNO3, isomeric with 14 · H2O, was obtained from the corresponding hydrochloride 7 · HCl and silver nitrate. Both nitrimines 7 and 14 gave 1,3,4,6‐tetranitro‐2,5‐dioxooctahydroimidazo[4,5‐d]imidazole 15 (66% and 59%) by treatment with nitric acid (100%) in acetic anhydride.
Ground state conformation of diphenylvinylphosphine sulfide and selenide
Authors: Pietrusiewicz K. Michał , Kuźnikowski Maciej , Wieczorek Wanda , Brandi Alberto 
Published: January 2005

AbstractSingle‐crystal X‐ray diffraction experiments have been performed on diphenylvinylphosphine sulfide (1): C14H13PS, space group P21/c, a = 10.186(1) Ǎ, b = 11.918(1) Å, c = 11.426 Å, β = 112.22(2)°, V = 1284.1(2) Å3, Z = 4, and diphenylvinylphosphine selenide (2): C14H13PSe, space group Pbca, a = 9.141 (3) Å, b = 16.458 (1) Å, c = 17.451 (1) Å, V = 2625.4 (9) Å3, Z = 8. The structures were solved by direct methods and were refined by full matrix least‐squares calculations to R = 0.046 and Rw = 0.058 using 2554 unique reflections with I > 3σ(I) in the case of 1, and to R = 0.052 and Rw = 0.065 using 1953 unique reflections with I > 3σ(I) in the case of 2. In close analogy to the previously studied vinyl phosphine oxides both 1 and 2 were found to exist in the s‐cis conformation with the pertinent CCPX dihedral angles equal to 12.5° and 2.9° for 1 and 2, respectively.
Oxygen‐17 nuclear magnetic resonance spectroscopy of organosulfur compounds. Part III. 17O NMR lanthanide‐induced shifts (LIS) of diastereotopic oxygen atoms in trans‐2‐ [alkyl(aryl)sulfonyl]cyclohexanols
Authors: Powers Thomas A. , Evans Slayton A. 
Published: January 2005

AbstractThe 17O NMR diastereotopicity or chemical shift differences of diastereotopic sulfonyl oxygens in a series of trans‐2‐[alkyl(aryl)sulfonyl]cyclohexanols have been determined. From a comparison of their sulfonyl oxygen 17O NMR lanthanide‐induced shifts, equilibrium distributions between diastereomeric sulfonyl oxygen‐Eu(fod)3 complexes were determined and found to be sensitive to both the steric size of the –SO2R substituent as well as the proximity of the C1 hydroxyl group.
Conformationally controlled intramolecular heterocyclization of 2,4‐diaminoperfluoro‐4‐methyl‐2‐pentenethiocyanate‐3
Authors: Popkova Vera Ya. , Antipin Mikhail Yu. , Vinogradova Lyudmila E. , Leites Larisa A. , Struchkov Yuri T. 
Published: January 2005

AbstractPerfluoro‐2‐methyl‐2‐pentene‐thiocyanate‐3 reacts with ammonia to give 2,4‐diaminoperfluoro‐4‐methyl‐2‐pentenethiocyanate‐3 (4) and 2‐aminoperfluoro‐4, 4‐dimethyl‐4,5‐dihydro‐5‐ethylidene‐1,3‐thiazole (5). Compound 4 is kinetically stable and at 150°C under‐goes rotational isomerization to afford the cyclic isomer 2‐amino‐4,4‐bis(trifluoromethyl)‐4,5‐dihydro‐5‐(1‐aminoperfluoroethylidene) ‐1,3‐thiazole (6). Intramolecular cyclizations, resulting in the thiazolines 5 and 6, proceed likewise via the Thorpe reaction. For compounds 4–6, X‐ray diffraction analyses were undertaken and IR spectra in solution and in solid state were investigated. It is supposed that a high kinetic preference for formation of 4 and the fact that it does not undergo spontaneous cyclization in ammonolysis stem from the NH …︁ N intramolecular hydrogen bonding between two amino groups.
Synthesis of N,P,S,Se‐containing mono‐ and bicyclic compounds in reactions of isothiocyanato‐ and diisothiocyanato(di)chloromethyl(thio) phosphonates with hydrosulfur(seleno) compounds
Authors: Kamalov R. M. , Stepanov G. S. , Chertanova L. F. , Gazikasheva A. A. , Pudovik M. A. , Pudovik A. N. 
Published: January 2005

AbstractReactions of phenyl isothiocyanato(di)chloro‐methyl(thio)phosphonates (1) with thiols in the presence of a base give rise to 2‐alkylthio‐4,5‐dihydro‐4‐oxo(thioxo)‐4‐phenoxy‐1,3,4‐thiazaphospholes (5). Some of these compounds can also be obtained by alkylation of 2,4‐dithioxo‐4‐phenoxy‐1,3,4‐thiazaphospholidine (4), which is formed in the reaction of phenyl isothiocyanatochloromethylthiophosphonate (1a) with sodium hydrosulfide. The interaction of 1a with H2Se and triethylamine results in the formation of 2,4‐dithioxo‐4‐phenoxy‐1,3,4‐selenazaphospholidine (8), which when alkylated affords 2‐alkylthio‐4,5‐dihydro‐4‐phenoxy‐4‐thioxo‐1,3,4‐selenazaphospholes (9) Diisothiocyanatodichloromethyl(thio)‐phosphonates (11) react with α‐toluenethiol in the presence of a base, giving rise to 3,7‐bis(benzylthio)‐1‐oxo(thioxo)bicyclo[3.3.0]‐4,6‐dithia‐2,8‐diaza‐1‐phosphocta‐2, 7‐dienes (13). By the interaction of phenyl isothiocyanatotrichlorome‐thylthiophosphonate (14) with ethanethiol and Et3N, S‐ethyl‐N‐(O‐phenyl(trichloromethyl)thiophosphonyl)dithiocarbamate triethylammonium salt (15) has been formed. The molecular structures of some P,N,S,Se‐containing heterocycles that we have synthesized have been studied by X‐ray diffraction.
Wittig reaction of 1‐dicyanomethyleneacenaphthen‐2‐one
Authors: Abdou Wafaa M. , Ganoub Neven A. F. 
Published: January 2005

AbstractThe Wittig reaction of the titled compound 2 with alkoxycarbonylmethylenetriphenylphosphoranes (1a,b) has been investigated and the reaction products 6, 10, and 11 isolated and identified. On the other hand, reaction of 2 with benzoylmethylenetriphenyl‐phosphorane (1c) proceeded only at high temperature, yielding 7c and 10. Mechanisms accounting for the formation of the adducts are discussed, and the synthetic utility of the products were tested.
Reactions of tellurium(IV) chloride, aryl‐, diaryl‐, and triaryl tellurium(IV) chlorides with pyrimidine‐2‐thiols
Authors: Singh Ajai K. , Singh Veena , Khandelwal Bishan L. 
Published: January 2005

Abstract1‐Substituted 4,4,6‐trimethyl‐1H, 4H‐pyrimidine‐2‐thiol(L), whose substituents are C6H5 (1), p‐CH3OC6H4 (2), p‐O2NC6H4 (3), n‐C4H9 (4), and NH2 (5), react with TeCl4, ArTeCl3 (Ar = C6H5, 4‐CH3OC6H4, or 4‐C2H5OC6H4), Ph2TeCl2, and Ph3TeCl, resulting in TeCl3(L–H), ArTeCl2(L–H), Ph2TeCl2.L, and Ph3TeCl.L types of compounds. Elemental analyses, molecular weights, conductances in solutions, IR, and 1H and 13C NMR spectral data of these compounds suggest that, in all of them, the pyrimidine‐2‐thiols ligate through sulfur only. In the first two types of derivatives, the thiol form of L reacts with tellurium moieties, resulting in the liberation of HCl. On the basis of these data TeCl3(L‐H) appears to exist as a dimer in which two Te atoms are probably 5‐coordinated and are bridged by two Cl. Tellurium in ArTeCl2(L‐H), Ph2TeCl2.L, and Ph3TeCl.L also appears to be 5‐coordinated. IR data suggest that the Te–S bond in Ph2TeCl2.L is weak and, therefore, because of partial dissociation, the molecular complexes exhibit lower molecular weights in CH3CN. Ph3TeCl.L in acetonitrile behaves as a 1:1 electrolyte. Attempts to synthesize N‐, S‐, and Te‐containing heterocycle ring compounds from TeCl3(1/2‐H) and ArTe(1/2‐H)Cl2 did not succeed.
A 1,5‐diaza‐2,4‐(λ4P+, λ6P−)‐diphosphorinane
Authors: Shevchenko Igor V. , Jones Peter G. , Fischer Axel , Schmutzler Reinhard 
Published: January 2005

AbstractThe oxidation of the 1,3‐diaza‐4,6‐diphosphorine 1 with tetrachloroorthobenzoquinone 2 led, unexpectedly, to the formation of 1,5‐dimethyl‐2,2‐bis(dimethyl‐amino)‐4,4,4,4‐bis‐(tetrachloro‐o‐phenylenedioxa)‐1,5‐diaza‐2,4‐λ4, λ6‐diphosphorinane‐6‐one 4, containing two phosphorus atoms of opposite formal charge and different coordination number. The X‐ray crystal structure analysis of 4 revealed the presence of a six‐membered ring with an unusual conformation.
Preparations and reactions of trifluoromethylthiocopper
Authors: Munavalli Shekar , Rossman David I. , Rohrbaugh Dennis K. , Ferguson C. Parker , Hsu Fu‐Lian 
Published: January 2005

AbstractTrifluoromethylthiocopper, a versatile reagent for the introduction of the trifluoromethylthio group into organic compounds, has been prepared in a crystalline form. The thiyl radicals, generated in situ from this precursor, cause the cleavage of the 3S bond of di‐ and trisulfides to give unsymmetrical di‐ and trisulfides. Unsymmeirical n‐butyl trifluoromethyl disulfide is formed by the cleaveage of the CS bond of n‐butyl sulfide.
Reactions of β‐nitrostyrenes with tert‐butylmercury halides in the presence of lodide lon
Authors: Russell Glen A. , Yao Ching‐Fa 
Published: January 2005

AbstractPhotolysis of t‐BuHgCl/KI with PhC(R2)C(R1)NO2 forms PhC(R2)C(R1)Bu‐t when R1 = R2 = H or in low yield when R1 = H, R2 = Ph. When R1 ≠ H, or when R2 = Ph, reactions with t‐BuHgI/KI/hv proceed mainly via PhC(R2)C(R1)NO2·‐, PhC(R2)C(R1)N(OBu‐t)O−HgX+, PhC(R2)C(R1)NO and PhC(R2)C(R1)N(OBu‐t)HgX to form a variety of novel products including the dimeric bisnitronic esters (6) with R1 = Me or Ph and R2 = H; PhCH(R2)C(R1) = NOBu‐t with R1 = Me or Ph and R2 = H or R1 = H and R2 = Ph; PhC(R2)(OBu‐t)C(R1)NOH with R1 = H or Me and R2 = Ph; and 3‐phenyl‐2‐R1‐indoles with R1 = H, Me, Ph, PhS or t‐BuS and R2 = Ph. Nitrosoaromatics react with t‐BuHgX in the dark to form ArN(OBu‐t)(OBu‐t)HgX+ which condenses with ArNO to form the azoxy compound. tert‐Butyl radicals will add to RNO2 [R = Ph, Ph2CCH, Ph2CC(Ph)] in the presence of t‐BuHgI2− to form products derived from RN(OBu‐t)O−HgI+.
The correlation of 11B NMR ASIS effects with MO‐derived charge densities for closo‐C2B5H7 and some chloro derivatives
Authors: Onak Thomas , Abdou Zahid J. , Abdou Gaby , Herrera Sergio 
Published: January 2005

AbstractAromatic‐solvent‐induced 11B NMR shifts (11B ASIS effects), observed for closo‐2, 4‐C2B5H7 and its 5‐chloro and 5, 6‐dichloro derivatives, are correlated to ab initio STO‐3G derived atom charge densities. A near linear relationship is found upon incorporating nearestneighbor charge density contributions.
Structure and derivatization of the product from carbonylation of lithium triethylborohydride
Authors: Hubbard John L. 
Published: January 2005

AbstractTreatment of the reactive product from carbonylation of lithium triethylborohydride with the electrophilic reagent chlorotrimethylsilane does not produce the expected α‐hydroxyborane derivative. Instead, a borinate arising through migration of a second ethyl group from boron to carbon is obtained. This result is rationalized in terms of the initial product being a borate having two possible constitutions. The borate nature of this initial product is confirmed by 11B NMR.
Solid state 13C NMR can distinguish between bronsted and Lewis acid adducts of amines
Authors: Ofori‐Okai Gabriel , Bank Shelton 
Published: January 2005

AbstractThe solid 13C NMR spectra of solid complexes of phenethylamine with SnCl4, Me3SnCl, AlCl3, and HCl are presented and discussed as a means of distinguishing between Bronsted and Lewis acid adducts of alkyl amines. Solution 13C NMR results are discussed in terms of species present in complex equilibria and their detection using the two NMR methods.
Synthesis and reactions of 2,2,2‐trihaloethyl α‐hydroxyiminobenzylphosphonates. The influence of the ester group on the chemistry of phosphonates
Authors: Breuer Eli , Mahajna Mahmoud 
Published: January 2005

AbstractArbuzov reactions of diethyl 2,2,2‐trihaloethyl phosphites (3) with benzoyl chloride afforded ethyl 2,2,2‐trihaloethyl benzoylphosphonates (4). The reactions of 4 with NH2OH.HCl led to the formation of methyl benzoate and ethyl methyl H‐phosphonate as a result of alcoholysis of 4, followed by alkoxy group exchange. Methanol solutions of benzoylphosphonates 4 were found by 31P NMR spectroscopy to contain considerable proportions of hemiacetals, 7, which undergo base‐catalyzed CP bond cleavage. The formation of hemiacetals from benzoylphosphonates 4 is suppressed in 2‐propanol, and in this solvent the corresponding oximes 2 could be obtained in good yields. Reactions of methyl benzoylphosphonochloridate (10) with 2,2,2‐trihaloethanols, in CH2Cl2, gave methyl 2,2,2‐trihaloethyl benzoylphosphonates (11) which could be converted directly to oximes 12 by NH2OH.HCl in a one‐pot procedure. In contrast to the previously studied dimethyl (E)‐α‐hydroxyiminobenzylphosphonate, which underwent thermal Beckmann rearrangement to afford N‐benzoylphosphoramidates, both (E) and (Z)‐trihaloethyl esters 2 and 12 underwent fragmentation to benzonitrile and to the corresponding dialkyl hydrogen phosphate, reflecting the increased electrophilicity of the phosphorus in these compounds. Demethylation of methyl esters 12 was effected smoothly by iodide or bromide ions to yield benzoylphosphonate salts 15, which in turn were converted to oxime salts 14 by treatment with hydroxylamine. In contrast, attempted deethylation of ethylesters 2 in refluxing acetonitrile led to benzonitrile and pyrophosphate type product as indicated by 31P spectroscopic examination of the reaction mixture. Oxime salts 14 behaved similarly when heated. Acidification of lithium 2,2,2‐trifluoroethyl α‐hydroxyiminobenzylphosphonate (14a) gave the corresponding hydrogen trifluoroethyl phosphonate (19a). The fragmentation of 19a in 0.6 N ethanolic hydrogen chloride to ethyl trifluoroethyl hydrogen phosphate and benzonitrile at room temperature had a T1/2 value of approx 18 hours, which is greater by a factor of 2 than that of the corresponding methyl ester. When the fragmentation of 19 was carried out in solvent mixtures of either water with methanol or 2‐propanol, or methanol with tbutanol, the composition of the solvents was reflected in the products, indicating a dissociative type mechanism, involving metaphosphate as reactive intermediates.
Preparation of α,α‐difluoromethylene functionalized sulfones
Authors: Yang Zhen‐Yu , Burton Donald J. 
Published: January 2005

AbstractSulfination of bromodifluoroacetate or acetamide 1 with sodium dithionite gives the corresponding sulfinates 2a, and 2b, respectively, which upon cuprous bromidc catalyzed allylation afford the allylsulfonyl‐difluoroacetate and acetamides. Phenyl‐ or alkylsulfonyldifluoroacetates and acetamides can be readily prepared from reaction of 1 with thiolates, followed by oxidation with hydrogen peroxide.
A novel method for the preparation of diborane from aluminum, ethyl chloride, boron oxide and hydrogen
Authors: Zhao Chengwen , Gu Yijian , Rui Zunhong , Lin Zhongqiang , Yin Huoming , Lu Guangyu , Tao Yusheng 
Published: January 2005

AbstractA novel method is described for the preparation of diborane from aluminum, ethyl chloride, boron oxide and hydrogen via three steps; deoxyalkylation of boron oxide, hydrogenation of triethylboron and liberation of diborane. The triethylboron was prepared from aluminum, ethyl chloride and boron oxide directly at 85–110°C in 88% yield, with aluminum trichloride as by‐product in 95% yield. In the presence of triethylamine and a hydrogen pressure of 130 kg/cm2, the triethylboron was hydrogenated at 200°C for 2 hours to produce borane‐triethylamine complex in 92% yield. The borane‐triethylamine complex was treated again at 80°C with the aluminum trichloride collected from the first step to liberate diborane in 94% yield. The overall reaction yield was 76%.
The preparation and reactions of protected glyphosate imidate, thioimidate, and thiono esters from N‐[diphenoxyphosphinylmethyl]glycinonitrile: Comparative reactivities of activated carboxylate versus phosphonate esters
Authors: Dutra Gerard A. , Finkes Michael J. , Sikorski James A. 
Published: January 2005

AbstractThe highly efficient syntheses of novel protected glyphosate imidate, thioimidate, and thiono ester derivatives are described starting from N‐[diphenoxyphosphinylmethyl]glycinonitrile 3b. The scope, utility and limitations in using each of these activated carboxylate functionalities for further transformations to new “masked” heterocyclic derivatives are defined. While the solution stability of the imidate and thioimidate series limited the synthetic application of these species, the corresponding thiono ester derivatives were valuable synthetic intermediates, providing a short, efficient route to the first glyphosate derivatives containing 1,3,4‐oxadiazole and 1,2,4‐triazole ring systems in place of the carboxylate group. These thiono esters thus undergo selective nucleophilic addition at this activated carboxylate center, while retaining the reactive diphenyl phosphonate moiety.
Interaction of molecular SiS with silver atoms in an argon matrix: IR spectrum and ab initio rationalization
Authors: Köppe Ralf , Schnöckel Hansgeorg , Jouany Claude , Gadea Florent Xavier , Barthelat Jean Claude 
Published: January 2005

AbstractCo‐condensation of silver atoms and SiS in an argon matrix leads to the formation of Ag(SiS). The IR spectrum can be interpreted in two different ways: Isotopic shifts (28Si/29Si, 28Si/30Si, 32S/34S) imply a side‐on coordination of SiS to silver. On the other hand, the SiS frequency and the isotopic shifts can be assigned to an isolated SiS− molecule. The SiS force constant is reduced from 5.0 mdyn/Å in free SiS to 3.9 mdyn/Å in AgSiS. Ab initio investigations confirm the formation of an ion pair Ag+(SiS)−, admitting some electron delocalization.