Study on the α-Thiocarbonylthioformamide Ⅲ——Reaction with trimethyl phosphite

α-Thiocarbonylthioformamide is a stable and almost unexplored class of compounds¹ which attracts us to study their properties and reactions. According to literature three-valenced phosphorus compound is easy to react with thiirane² and thiocarbonate³ to form C=C double bond. So we want to explore the reaction of α-thiocarbonylthioformamide with three-valenced phosphorus compound. In initial experiment, we explored the reaction of α-thiobenzoylthioformmorpholine (1a) with trimethyl phosphite in dry diethyl ether at room temperature.     

三种O－异戊烯基苯丙素类天然产物的首次合成

以香草醛为起始原料，经O－异戊烯基化、Witting反应、水解、还原、氧化等 反应步骤，首次合成了三种苯丙素天然产物boropinalA（1），boropinalC（2） boropinicAcid（3）,有化合物结构均由核磁共振氢谱，质谱及红外光谱确证，用 X射线衍射法测定了3的晶体及分子结构。     

Addition products of a P(III)-isothiocyanate to dialkyl acetylenedicarboxylates: a spirocyclic phosphinimine and a triphosphorus heterocycle with tetra- and penta-coordinate phosphorus

Treatment of the P(III) isothiocyanate CH2[6-t-Bu-4-Me-C6H2O]2PNCS (1) with dimethyl acetylenedicarboxylate (DMAD) or diethyl acetylenedicarboxylate (DEAD) yields the spirocyclic phosphinimines CH2[6-t-Bu-4-Me-C6H2O]2P[NC(S)C(CO2R)C(CO2R)][R=Me (2), Et (3)], in a reaction unlike those of organic isocyanates. From the reaction of 1 with DEAD, a second product, the triphosphorus compound 5, with the composition [2x1+3] but with a completely reorganized structure {CH2[6-t-Bu-4-Me-C6H2O]2P=C(CO2Et)C(CO2Et)=CN-}{CH2[6-t-Bu-4-Me-C6H2O]2P(NCS)}-SC=N-P(S)[(OC6H2-6-t-Bu-4-Me)2CH2] with tetra- and penta-coordinate phosphorus, is also isolated. Structure and reactivity of these compounds are discussed. Addition of 2,2,2-trifluoroethanol to 2 or 3 leads to the pentacoordinate phosphorus compounds [CH2(6-t-Bu-4-Me-C6H2O)2P(OCH2CF3){C(CO2R)C(CO2R)-C(S)-NH-}][R=Me (6), Et (7)]. The phosphonate [CH2(6-t-Bu-4-Me-C6H2O)2P(O)C(CO2Et)=C(CO2Et)-C(S)-NH2] (8) is obtained by evaporating a solution of 7 in open air.     

Metallderivate von Molekülverbindungen. VII. Bis[1,2-bis(dimethylamino)ethan-N,N′]lithium-disilylphosphanid — Synthese und Struktur

Metal Derivatives of Molecular Compounds. VII. Bis[1,2-bis(dimethylamino)ethane-N,N′]lithium Disilylphosphanide — Synthesis and Structure Crystalline lithium phosphanides studied so far show a remarkably high diversity of structure types dependent on the ligands at lithium and the substituents at phosphorus. Bis[1,2-bis(dimethylamino)ethane-N,N′]lithium disilylphosphanide ( 1 ) discussed here, belongs to the up to now small group of compounds which are ionic in the solid state. It is best prepared from silylphosphane by twofold lithiation with lithium dimethylphosphanide first and subsequent monosilylation with silyl trifluoromethanesulfonate, followed by complexation. As found by X-ray structure determination (wR = 0.038) on crystals obtained from diethyl ether {monoclinic; space group P2₁/c; a = 897.8(1); b = 1 673.6(2); c = 1 466.8(1) pm; β = 90.73(1)° at ?100 ± 3°C; Z = 4 formula units}, the lithium cation is tetrahedrally coordinated by four nitrogen atoms of two 1,2-bis(dimethylamino)ethane molecules. Characteristic parameters of the disilylphosphanide anion are a shortened average P? Si bond length of 217 pm (standard value 225 pm) and a Si? P? Si angle of 92.3°.     

Temperature-dependent rate constants for the gas-phase reactions of OH radicals with 1,3,5-trimethylbenzene, triethyl phosphate, and a series of alkylphosphonates

Rate constants for the reactions of OH radicals with dimethyl methylphosphonate [DMMP, (CH3O)2P(O)CH3], dimethyl ethylphosphonate [DMEP, (CH3O)2P(O)C2H5], diethyl methylphosphonate [DEMP, (C2H5O)2P(O)CH3], diethyl ethylphosphonate [DEEP, (C2H5O)2P(O)C2H5], triethyl phosphate [TEP, (C2H5O)3PO] and 1,3,5-trimethylbenzene have been measured over the temperature range 278-348 K at atmospheric pressure of air using a relative rate method. alpha-Pinene (for DEMP, DEEP, TEP and 1,3,5-trimethylbenzene) and di-n-butyl ether (for DMMP and DMEP) were used as the reference compounds, and rate constants for the reaction of OH radicals with di-n-butyl ether were also measured over the same temperature range using alpha-pinene and n-decane as the reference compounds. The Arrhenius expressions obtained for these OH radical reactions (in cm3 molecule(-1) s(-1) units) are 8.00 x 10(-14)e(1470+/-132)/T for DMMP (296-348 K), 9.76 x 10(-14)e(1520+/-14)/T for DMEP (296-348 K), 4.20 x 10(-13)e(1456+/-227)/T for DEMP (296-348 K), 6.46 x 10(-13)e(1339+/-376)/T for DEEP (296-348 K), 4.29 x 10(-13)e(1428+/-219)/T for TEP (296-347 K), and 4.40 x 10(-12)e(738+/-176)/T for 1,3,5-trimethylbenzene (278-347 K), where the indicated errors are two least-squares standard deviations and do not include the uncertainties in the rate constants for the reference compounds. The measured rate constants for di-n-butyl ether are in good agreement with literature data over the temperature range studied (278-348 K).     

State in solution, structure, and regioselectivity of reactions of the lithium 1-(2-methoxyphenyl)-3,3-diphenylpropyne derivative

According to the spectrophotometric data, the lithium 1-(2-methoxyphenyl)-3,3-diphenylpropyne derivative in diethyl ether exists as contact ion pairs, while in THF, according to the spectrophotometric and¹³C NMR data, solvent-separated ion pairs are predominantly formed. According to the¹³C NMR data, the carbanion in the solventseparated ion pairs has a structure close to the propargylic type. The regioselectivity of reactions of the lithium derivative with ethyl halides in diethyl ether, THF, and hexamethyphosphoramide, with benzyl chloride in the first two solvents, and with methanol in THF were studied. The protonation with methanol proceeds exclusively at the allenylic center (C-1) while the ethylation and especially benzylation proceed predominantly at the propargylic center (C-3). The selectivity of ethylation of the propargylic center of both solvent-separated ion pairs in THF and contact ion pairs in diethyl ether increases as the hardness of the ethylating agent increases, and in the case of the same ethyl halide, the selectivity increases from the solvent-separated ion pairs to the contact ion pairs. The spectral data obtained and the data on changes in the regioselectivity do not allow one to believe that the contact ion pairs of the lithium derivative in ether exhibit the intramolecular coordination of the lithium cation to the methoxy group, which might lead to the allenylic structure of contact ion pairs of this derivative. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2043–2051, November, 1997.     

Hydrogallation of alkynes with H-GaCl2: formation of organoelement dichlorogallium compounds potentially applicable as chelating Lewis acids

Treatment of trimethylsilylethynylbenzenes C6H6-x(C[TRIPLE BOND]C-SiMe3)x(x=1-3) with the hydridodichlorogallium compound H-GaCl2 afforded, almost quantitatively, the alkenylphenyl compounds C6H6-x[C(H)C(SiMe3)-GaCl2]x[x=1 (6), 2 (7), and 3 (8)] by hydrogallation. Only compound 6 was readily soluble in n-hexane; it formed dimers via Ga-Cl bridges. The bisalkenyl compound 7 was only sparingly soluble; its molecular structure consisted of a singular dimeric formula unit with a cyclophane-type constitution and two bridging Ga 2Cl 2 heterocycles. The overall structure may be described by a molecular box formed by a large macrocycle comprising 22 Ga, C, and Cl atoms. Compound 8 proved to be insoluble in hydrocarbon solvents. Its molecular structure could not be detected. Extraction of the solid raw products of 7 and 8 with diethyl ether yielded small quantities of the ether adducts C6H6-x[C(H)C(SiMe3)-GaCl2(OEt2)]x(x=2, 3) [7(OEt2)2 and 8(OEt2)3], both of which are monomeric because of the coordinative saturation of their gallium atoms. The tetraalkyne 1,2,4,5-tetrakis(trimethylsilylethynyl)benzene gave a different reaction course. Complete hydrogallation resulted in the release of 2 equiv of GaCl3, and neighboring alkenyl groups of the product 9 were connected by GaCl bridges to form seven-membered heterocycles and an overall tricyclic compound. Compound 9 was characterized as a diethyl ether adduct.     

Synthesis of Symmetrical Bis-(2-chloro-1,3,2-benzodiazaphosphorinones) Hydrolysis and Fluorination of Selected Compounds

The series of symmetrical bis-amides 3 was formed by the reaction of N-methylisatoic anhydride ( 1 ), with the diamines 2 . Reaction of 3 with phosphorus trichloride led to the formation of the symmetrical bis-(1,3,2-benzodiazaphosphorinones) ( 4 ). 4 c , 4 d and 4 e were easily hydrolyzed in moist air, leading to the formation of 5 c , 5 d and 5 e . In the presence of triethylamine, 4 c , 4 d and 4 e were allowed to react with Et₃N · 3 HF to give the symmetrical bis-P–F derivatives 6 c , 6 d and 6 e , which could be readily oxidized by (NH₂)₂C(:O) · H₂O₂, leading to the formation of a series of P(:O)F compounds 7 c , 7 d and 7 e . All compounds were characterized unambiguously by ¹H, ¹³C, ¹⁹F, and ³¹P-NMR-spectroscopy, mass spectrometry, and elemental analysis. All the bis-amides and bis-(1,3,2-benzodiazaphosphorinones), except 4 b and 4 f , exist as single conformers in common solvents such as toluene, diethyl ether, dichloromethane or chloroform. For compound 6 c , a single crystal X-ray structure analysis was conducted. The molecule displays crystallographic inversion symmetry.     

Li- and P NMR spectra of cyclopentanone lithium enolate in ethereal solvents: identification of the HMPA-coordinated aggregate structures

The structures of cyclopentanone lithium enolate under HMPA titration in 0.04-0.8 M diethyl ether and dimethyl ether solvents have been investigated using the low-temperature ⁷Li, ³¹P, and ¹³C NMR. The progressive solvation by HMPA occurs for the tetra- and dimeric enolates, and upon addition of >2 equiv. of HMPA, the lithium enolate has been converged on a mixture of tetra-HMPA coordinated tetramer and bis-HMPA coordinated dimer with the ratio of 5:95 and <1:99 in diethyl ether and dimethyl ether, respectively. Neither monomeric nor trimeric enolate is detectable under such HMPA titration.     

Correlation between the 6Li,15N coupling constant and the coordination number at lithium

The 6Li,15N coupling constants of lithium amide dimers and their mixed complexes with n-butyllithium, formed from five different chiral amines derived from (S)-[15N]phenylalanine, were determined in diethyl ether (Et2O), tetrahydrofuran (THF) and toluene. Results of NMR spectroscopy studies of these complexes show a clear difference in 6Li,15N coupling constants between di-, tri- and tetracoordinated lithium atoms. The lithium amide dimers with a chelating ether group exhibit 6Li,15N coupling constants of approximately 3.8 and approximately 5.5 Hz for the tetracoordinated and tricoordinated lithium atoms, respectively. The lithium amide dimers with a chelating thioether group show distinctly larger 6Li,15N coupling constants of approximately 4.4 Hz for the tetracoordinated lithium atoms, and the tricoordinated lithium atoms have smaller 6Li,15N coupling constants, approximately 4.9 Hz, than their ether analogues. In diethyl ether and tetrahydrofuran, mixed dimeric complexes between the lithium amides and n-butyllithium are formed. The tetracoordinated lithium atoms of these complexes have 6Li,15N coupling constants of approximately 4.0 Hz, and the 6Li,15N coupling constants of the tricoordinated lithium atoms differ somewhat, depending on whether the chelating group is an ether or a thioether; approximately 5.1 and approximately 4.6 Hz, respectively. In toluene, mixed trimeric complexes are formed from two lithium amide moieties and one n-butyllithium. In these trimers, two lithium atoms are tricoordinated with 6Li,15N coupling constants of approximately 4.6 Hz and one lithium is dicoordinated with 6Li,15N coupling constants of approximately 6.5 Hz.     

Di(benzothiazol-2-yl)phosphanide as a Janus-head ligand to caesium

Starting from tris(benzothiazol-2-yl)phosphane (1) an advanced Janus-head ligand, di(benzothiazol-2-yl)phosphane (2), was synthesised and structurally characterised. The heteroaryl substituents of this ligand provide both hard and soft donor sites. Surprisingly, the phosphorus atom in 2 is divalent and the hydrogen atom is directly bonded to one ring nitrogen atom and hydrogen bonded to the second. Compound 2 decomposes in any common solvent other than diethyl ether and a new preparation to improve the yields of 2 is presented. A coordination polymer, [{Cs(bth)(2)P}8] (3) (bth=benzothiazol-2-yl), was obtained when the sec-phosphane 2 was allowed to react with elemental caesium in a 1:1 ratio in diethyl ether at -78 degrees C. In 3 each anion is coordinated to four caesium cations and vice versa. The central phosphorus atom is coordinated to two metal atoms above and below the mean plane of the anion in positions in which the two lone pairs of a four-electron donor are anticipated. Two additional cations micro-bridge both ring nitrogen atoms. Hence both faces of the Janus-head ligand are coordinated to the same number of metal cations but in a different way.     

Separation and spectrophotometric determination of trace quantities of lithium in high-purity beryllium and beryllium oxide

A spectrophotometric method is described for the determination of trace quantities of lithium in beryllium metal and its oxide. Lithium is selectively separated from beryllium by extraction from 1M potassium hydroxide solution into 0.1M dipivaloylmethane in diethyl ether. Fluoride, added before the extraction, successfully masks the beryllium; as little as 3 microg of lithium can be separated from as much as 1 g of beryllium. The lithium is then back-extracted into 0.1M hydrochloric acid and is determined spectrophotometrically with o-(2-hydroxy-3,6-disulpho-1-naphthylazo) benzene arsonic acid, Thoron. In an acetone-water medium Beer's law is obeyed over the range 0.1-1.0 microg ml. The method has been applied successfully to the determination of lithium in concentrations as low as 3 ppm; the relative standard deviation for the determination of 200 ppm is 3%.     

Alkali metal complexes of a naphthylamine-substituted phosphanide

The reaction between {(Me3Si)2CH}PCl2 and one equivalent of [C10H6-8-NMe2]Li, followed by in situ reduction with LiAlH4, gives the secondary phosphane {(Me3Si)2CH}(C10H6-8-NMe2)PH(1) in good yield as a colourless crystalline solid. Metalation of 1 with Bu(n)Li in diethyl ether gives the lithium phosphanide [{[{(Me3Si)2CH}(C10H6-8-NMe2)P]Li}2(OEt2)](2), which undergoes metathesis with either NaOBu(t) or KOBu(t) to give the heavier alkali metal derivatives [[{(Me3Si)2CH}(C10H6-8-NMe2)P]-Na(tmeda)](3) and [[{(Me3Si)2CH}(C10H6-8-NMe2)P]K(pmdeta)](4), after recrystallisation in the presence of the corresponding amine co-ligand [tmeda = N,N,N',N'-tetramethylethylenediamine, pmdeta = N,N,N',N",N"-pentamethyldiethylenetriamine]. Compounds 2-4 have been characterised by 1H, 13C{1H} and 31P{1H} NMR spectroscopy, elemental analyses and X-ray crystallography. Dinuclear 2 crystallises with the phosphanide ligands arranged in a head-to-head fashion and is subject to dynamic exchange in toluene solution; in contrast, compounds 3 and 4 crystallise as discrete monomers which exhibit no dynamic behaviour in solution. DFT calculations on the model compound [{[(Me)(C10H6-8-NMe2)P]Li},(OMe2)] (2a) indicate that the most stable head-to-head form is favoured by 15.0 kcal mol(-1) over the corresponding head-to-tail form.     

The Synthesis of Phosphonate Ester Containing Fluorinated Vinyl Ethers

Three novel perfluorovinyl ethers containing phosphonate ester groups, diethyl 1,1,2,2,3,3,5,6,6-nonafluoro-4-oxa-5-hexenylphosphonate, (EtO)(2)P(O)(CF(2))(3)OCF=CF(2) (1), diethyl 1,1,2,2,4,5,5-heptafluoro-3-oxa-4-pentenylphosphonate, (EtO)(2)P(O)(CF(2))(2)OCF=CF(2) (2), and diethyl 1,1,2,2,4,5,5,7,8,8-decafluoro-4-trifluoromethyl-3,6-dioxa-7-octenylphosphonate, CF(2)=CFOCF(2)CF(CF(3))O(CF(2))(2)P(O)(OEt)(2) (3), have been synthesized. Perfluorovinyl ethers 1 and 2 were synthesized from methyl 4-trifluoroethenoxy-2,2,3,3,4,4-hexafluorobutanoate and methyl 3-trifluoroethenoxy-2,2,3,3-tetrafluoropropanoate, respectively, while perfluorovinyl ether 3 was synthesized either from 5-trifluoroethenoxy-4-trifluoromethyl-3-oxa-1,1,2,2,4,5,5-heptafluoropentylsulfonyl fluoride or methyl 6-trifluoroethenoxy-5-trifluoromethyl-4-oxa-2,2,3,3,5,6,6-heptafluorohexanoate. The carboxylate esters were converted to the corresponding fluoroalkyl iodides via a free-radical iododecarboxylation. The sulfonyl fluoride was converted to its corresponding fluoroalkyl iodide via iododesulfination. The intermediate iodides were found to be useful precursors for the incorporation of the phosphonic ester groups via a photoreaction with tetraethyl pyrophosphite to produce diethyl fluorophosphonites. The diethyl fluorophosphonites were oxidized to the desired phosphonates, 1, 2, and 3, utilizing hydrogen peroxide as the oxidant. Moderate to good overall yields of perfluorovinyl ethers 1-3 have been achieved.     

TheO,O′-dibenzoyl derivative of (R,R)-tartaric acid as a host compound for simple organic ethers

TheO, O-dibenzoyl derivative of (R, R)-tartaric acid shows a good inclusion ability for diethyl and di-n-propol ethers. The two crystalline inclusion compounds have 1:1 stoichiometry and reveal isomorphous structures. Hydrogen bonded host molecules form chains running along thez axis of the unit cell and guest molecules join to these chains by short O–H...O hydrogen bonds. Hydrogen bonding in the crystals is characterized by a C(7)D first-order network. The ether molecules are in a fully extended conformation. They are accommodated in channel-like voids running along thex axis. Atomic displacement parameters are significantly larger for diethyl ether than for the di-n-propyl ether molecule reflecting less dense packing for this inclusion compound.Supplementary Data: relating to this article are deposited with the British Library as Supplementary Publication No. SUP 82195 (19 pages)     

The relation between ion pair structures and reactivities of lithium cuprates

From Li+ well-solvating solvents or complex ligands such as THF, [12]crown-4, amines etc., lithium cuprates R2CuLi(*LiX) crystallise in a solvent-separated ion pair (SSIP) structural type (e.g. 10). In contrast, solvents with little donor qualities for Li+ such as diethyl ether or dimethyl sulfide lead to solid-state structures of the contact ion pair (CIP) type (e.g. 11). 1H,6Li HOESY NMR investigations in solutions of R2CuLi(*LiX) (15, 16) are in agreement with these findings: in THF the SSIP 18 is strongly favoured in the equilibrium with the CIP 17, and in diethyl ether one observes essentially only the CIP 17. Salts LiX (X=CN, Cl, Br, I, SPh) have only a minor effect on the ion pair equilibrium. These structural investigations correspond perfectly with Bertz's logarithmic reactivity profiles (LRPs) of reactions of R2CuLi with enones in diethyl ether and THF: the faster reaction in diethyl ether is due to the predominance of the CIP 17 in this solvent, which is the reacting species; in THF only little CIP 17 is present in a fast equilibrium with the SSIP 18. A kinetic analysis of the LRPs quantifies these findings. Recent quantum-chemical studies are also in agreement with the CIP 17 being the reacting species. Thus a uniform picture of structure and reactivity of lithium cuprates emerges.     

REDUCTION OF TERMINAL ORGANYLCHALCOGENO PHOSPHONATES AS A WAY TO PREPARE PRIMARY ORGANYLCHALCOGENO PHOSPHINES

2-Organylseleno(telluro)ethyl phosphines and 4-organylthio(seleno (telluro))butyl phosphines were prepared by reduction of diethyl 2-organylseleno(telluro)ethyl phosphonates and diethyl 4-organylthio(seleno(telluro)) butyl phosphonates with lithium aluminium hydride in diethyl ether. ¹H and ³¹P NMR spectra as well as mass spectra of the resulting phosphines were considered. Their stability in regard to the oxidation by oxygen was discussed.     

Synthese und struktur von dicyclopentadienyl(trimethylsilyl)titanchlorid

Dicyclopentadienyl(trimethylsilyl)titanium chloride, a stable trimethylsilyltitanium compound, is synthesized by reaction of dicyclopentadienyltitanium dichloride and tris(trimethylsilyl)aluminium, coordinated with diethyl ether, or lithium tetarakis(trimethylsilyl)aluminate. The IR and NMR spectra are reported. The crystal structure of the title compound has been determined. It shows a distorted tetrahedral surrounding of the titanium atom; the Ti–Si distance is 267 pm.     

3-Cyanopyridine-2(1H)-thiones and 3-cyano-2-(methylthio)pyridines in the synthesis of substituted 3-(aminomethyl)pyridines

The reactions of substituted 3-cyanopyridine-2(1H)-thiones and 3-cyano-2-(methylthio)pyridines with lithium aluminum hydride in anhydrous diethyl ether afforded the corresponding 3-aminomethyl derivatives, which were used in the synthesis of the corresponding amides.     

Über Chalkogenolate. 89. Untersuchungen über N-Dicyandithiocarbamidsäure Darstellung und Eigenschaften der freien Säure

On Chalcogenolates. 89. Studies on N-Dicyandithiocarbamic Acid. Preparation and Properties of the Free Acid Colorless N-dicyandithiocarbamic acid (melting point: 112°C) has been prepared by reaction between a suspension of K[S₂C? N(CN)₂] in diethyl ether and a solution of HCl in (C₂H₅)₂O at 0°C; the ether was distilled off at 0°C in vacuo. The compound has been characterized by means of infared spectra, electron absorption spectra, ¹H-NMR spectra, and mass spectra. The dissociation constant of N-dicyandithiocarbamic acid in water is K_a = (1.69 ± 0.1) X 10^?1 20°C. The thermodynamic data of the dissociation were calculated.