Mechanism of the sulfurisation of phosphines and phosphites using 3-amino-1,2,4-dithiazole-5-thione (xanthane hydride)

Contrary to a previous report, the sulfurisation of phosphorus(III) derivatives by 3-amino-1,2,4-dithiazole-5-thione (xanthane hydride) does not yield carbon disulfide and cyanamide as the additional reaction products. The reaction of xanthane hydride with triphenyl phosphine or trimethyl phosphite yields triphenyl phosphine sulfide or trimethyl thiophosphate, respectively, and thiocarbamoyl isothiocyanate which has been trapped with nucleophiles. The reaction pathway involves initial nucleophilic attack of the phosphorus at sulfur next to the thiocarbonyl group of xanthane hydride followed by decomposition of the phosphonium intermediate formed to products. The Hammett rho-values for the sulfurisation of substituted triphenyl phosphines and triphenyl phosphites in acetonitrile are approximately -1.0. The entropies of activation are very negative (-114+/-15 J mol-1 K-1) with little dependence on solvent which is consistent with a bimolecular association step leading to the transition state. The negative values of DeltaS(not equal) and rho values indicate that the rate limiting step of the sulfurisation reaction is formation of the phosphonium ion intermediate which has an early transition state with little covalent bond formation. The site of nucleophilic attack has been also confirmed using computational calculations.     

Synthesis of thiazole aminophosphine oxides, aminophosphonic and aminophosphinic acids and Cu(II) binding abilities of thiazole aminophosphonic acids

A series of new aminophosphine oxides, aminophosphonic and aminophosphinic acids derived from thiazole was synthesized by addition of phosphine oxides or silylated phosphorus esters to the corresponding thiazole aldimines. The thiazole aldimines were obtained from 2-thiazole aldehyde and primary amines by a standard procedure. The corresponding phosphine oxides were obtained by alkylation of diethyl phosphite or ethyl phenylphosphinate with the appropriate Grignard reagents. The silylated phosphorus esters were prepared from trimethyl phosphite and from methyl- or phenylphosphinic ethyl ester by treatment with bromotrimethylsilane. The coordination ability towards Cu(II) ions are described for two obtained aminophosphonate ligands.     

Tris(tetramethylguanidinyl)phosphine: The Simplest Non-ionic Phosphorus Superbase and Strongly Donating Phosphine Ligand

We report the synthesis and properties of the much sought-after tris(1,1,3,3-tetramethylguanidinyl) phosphine P(tmg)₃, a crystalline, superbasic phosphine accessible through a short and scalable procedure from the cheap and commercially available bulk chemicals 1,1,3,3-tetramethylguanidine, tris(dimethylamino)-phosphine and phosphorus trichloride. The new phosphine exhibits exceptional electron donor properties and readily forms transition metal complexes with gold(I), palladium(II) and rhodium(I) precursors. The formation of zwitterionic Lewis base adducts with carbon dioxide and sulfur dioxide was explored. In addition, the complete series of phosphine chalcogenides was prepared from the reaction of P(tmg)₃ with N₂O and the elemental chalcogens.     

Synthesis of transient and stable C-amino phosphorus ylides and their fragmentation into transient and stable carbenes

Only basic phosphines, such as tris(dimethylamino)phosphine, allow for the synthesis of a stable acyclic beta-amino phosphonium salt 1c, which upon deprotonation with butyllithium affords the corresponding stable C-amino phosphorus ylide 2c. In contrast, cyclic beta-amino phosphonium salts 5a and 5b are stable despite the presence of weakly basic triarylphosphine fragments. They are prepared by intramolecular insertion of the carbene center of (amino)(phosphonio)carbenes into the CH bond of a phosphorus substituent. Deprotonation of 5a leads to the corresponding cyclic C-amino phosphorus ylide 6a, which has been fully characterized including an X-ray diffraction study. Deprotonation of 5b affords enamine 8, probably via fragmentation of ylide 6b into transient carbene 7b and a subsequent 1,2-hydrogen shift. Transient cyclic C-amino phosphorus ylides 6c and 6d have been prepared by intramolecular addition of a carbanion generated by deprotonation of a phosphorus substituent. Three-membered heterocycle 6c rearranges into alkene 9, whereas the four-membered ring system undergoes a ring opening affording the stable carbene 7d. The latter results pave the route for the synthesis of various mixed carbene-phosphine bidentate ligands.     

Alpha-monodeuterated benzyl alcohols and phosphobetaines from reactions of aromatic aldehydes with a water/D2O-soluble phosphine

With the aim of learning more about the bleaching action of pulps by (hydroxymethyl)phosphines, we reacted several benzaldehydes, containing MeO, Me, OH, or halogen substituents, with tris(3-hydroxypropyl)phosphine, [HO(CH2)3]3P, in aqueous solution at 90 degrees C under argon. Effective reduction of the aldehydes to the corresponding benzyl alcohols with concomitant oxidation of the phosphine to the phosphine oxide takes place, the reaction proceeding via an initially formed phosphonium species. When the reactions are carried out in D2O, the benzyl alcohol product from 3,4-dimethoxybenzaldehyde contains one deuterium atom at the benzyl-carbon atom, consistent with the last step of the mechanism involving a carbanion intermediate. With syringaldehyde (3,5-dimethoxy-4-hydroxy-benzaldehyde), the reduction product (syringyl alcohol) is more reactive toward the phosphine than is the starting aldehyde, and a zwitterionic, phosphobetaine product is formed. In D2O, the zwitterion benzyl protons and protons of the hydroxypropyl-CH2 adjacent to the P atom undergo H/D exchange via presumed phosphorus ylide intermediates. Under the same aqueous reaction conditions, tris(3-hydroxypropyl)phosphine, [HO(CH2)3]3P (THPP), does not undergo redox reactions with aliphatic aldehydes but simply promotes a base-catalyzed self-condensation (aldol) reaction. THPP reduction of an aromatic ketone is sluggish, presumably because the carbonyl C-atom is less electrophilic than that present in an aromatic aldehyde.     

Gas-phase reactivity of the O=P(OCH3)2 + phosphonium ion towards alpha,beta-unsaturated esters in a quadrupole ion trap

Ion-molecule reactions between the O=P(OCH3)2 + phosphonium ions and eight alpha,beta-unsaturated esters (methyl acrylate, ethyl acrylate, methyl crotonate, ethyl crotonate, methyl 3,3-dimethylacrylate, ethyl 3,3-dimethylacrylate, methyl methacrylate and ethyl methacrylate) were performed in a quadrupole ion trap mass spectrometer. The O=P(OCH3)2 + phosphonium ions, formed by electron ionization from neutral trimethyl phosphite, were found to react with alpha,beta-unsaturated esters to give an adduct [RR'C=CR'COOR', O=P(OCH3)2]+, which lose spontaneously a molecule of trimethyl phosphate (R'=CH3) or dimethyl ethyl phosphate (R'=C2H5). An ion corresponding to a protonated trialkyl phosphate is also observed when substituent R'=H. To confirm the experimental results, and to elucidate the mechanism for the formation of the ionic species, a theoretical study using the density functional theory (DFT) approach was carried out. The potential energy surface obtained from B3LYP/6-31G(d,p) calculations for the reaction between O=P(OCH3)2 + and methyl acrylate is described.     

First asymmetric Abramov-type phosphonylation of aldehydes with trialkyl phosphites catalyzed by chiral Lewis bases

Chiral phosphine oxides (Lewis bases) catalyze silicon tetrachloride-mediated, enantioselective phosphonylation of aldehydes with trialkyl phosphites (Abramov-type reaction), which leads to optically active α-hydroxyphosphonates with moderate enantioselectivities. ³¹P NMR analysis of the phosphonylation of benzaldehyde with triethyl phosphite supports the assumed reaction mechanism.     

Reaction of derivatives of trivalent phosphorus with 2-oxo-1,3-dithio-1,3-diphenylpropane

Conclusions When trimethyl phosphite, tri(dimethylamino)phosphine, triphenylphosphine, and dimethylphosphorous acid are reacted with 2-oxo-1,3-dithio-1,3-diphenylpropane the latter is desulfurized and deoxidized.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2101–2103, September, 1976.The authors express their gratitude to É. L Gol'dfarb for taking the³¹P NMR spectra.     

Reactions of polyfluoroalkanethioamides with tris(diethylamino)phosphine

Structure of reaction products obtained from tris(diethylamino)phosphine with N,Ndialkylpolyfluoroalkanethioamides depends on the length of the polyfluoroalkyl substituent in the latter. In the case of morpholides of perfluorothiopropionic and perfluorothiobutyric acids the main reaction products are fluoro-containing aminoacetylenes: 4-(perfluoroalkan-1-yn-1-yl)morpholines, and also tris(diethylamino)phosphine sulfide and tris(diethylamino)difluorophosphorane. From morpholides or piperidides of ω-H-perfluorothiovaleric acid with a longer perfluoroalkyl substituents amides of cis- and trans-perfluoropent-2-enethiocarboxylic acids were obtained.     

Reactions of bis(trifluoromethyl)nitroxyl with (CF3)3M (M=P,Sb) and properties of bis(trifluoromethyl)nitroxy derivatives of P,As and Sb

Bis(trifluoromethyl)nitroxyl gives an addition reaction with tris(trifluoromethyl)phosphine and radical exchange reactions with stibine. The mechanisms of the above reactions and the properties of bis(trifluoromethyl)nitroxy derivatives of phosphorus, arsenic and antimony are discussed.     

Synthesis and Reactivity of New Organophosphorus Compounds

Abstract

Synthesis of functionally substituted organophosphorus compounds on the basis of reactions of the tri-n-butylphosphine/carbon disulfide, tri-n-butylphosphine/phenylisothiocyanate, tris(dimethylamino)phosphine/phenylisothiocyanate adducts with a wide range of different dipolarophiles are reported. The development of application of S-Li tri-n-butylphosphonio-dithioformiate derivatives to the synthesis of new types of organophosphorus compounds are reported.     

Cyclisation reactions of 2-substituted benzoylphosphonates with trialkyl phosphites via nucleophilic attack on a carbonyl-containing ortho substituent

Dimethyl 2-acetoxy- and dimethyl 2-benzoyloxy-benzoylphosphonate undergo cyclisation and deoxygenation in the presence of excess trimethyl phosphite to give dimethyl (3-methyl-1-benzofuran-2-yl)phosphonate and dimethyl (3-phenyl-1-benzofuran-2-yl)phosphonate, respectively. The reaction pathway has been shown to involve phosphite attack on initially formed tricyclic dioxaphospholane intermediates with the subsequent loss of two molecules of trimethyl phosphate. In the absence of additional trimethyl phosphite the initially formed tricyclic dioxaphospholane intermediates lose one molecule of trimethyl phosphate and then undergo a novel rearrangement to give β-ketophosphonates. The mechanism for this reaction helps explain some previously reported epoxide rearrangements. In contrast, the initially formed anionic intermediate from the reaction of dimethyl 2-benzoyloxymethylbenzoylphosphonate with trimethyl phosphite undergoes decomposition to give a carbene intermediate which is trapped by the trimethyl phosphite to give an ylidic phosphonate.     

Preparation of chlorofluoromethylene olefins via phosphine dechlorination of dichlorofluoromethyltris?dimethylamino?phosphonium chloride

The reaction of dichlorofluoromethyltris?dimethylamino?phosphonium chloride with tertiary phosphines provides a convenient preparation of the chlorofluoromethylenetris?dimethylamino?phosphonium ylide. This ylide provides reasonable yields of chlorofluoroolefins from aldehydes, activated ketones, non-activated ketones, and activated esters. The mechanism of phosphonium salt formation was shown to involve positive chlorine abstraction from CFCl₃ by (Me₂N)₃P followed by recombination of the intermediate ion pair. Dechlorination of the resulting dichlorofluoromethyltris?dimethylamino?phosphonium chloride by triphenylphosphine gave an olefinating solution of reasonable stability. In contrast, the solution obtained by dechlorination of the phosphonium salt by tris?dimethylamino?-phosphine showed no stability.     

An extremely efficient three-component reaction of aldehydes/ketones, amines, and phosphites (Kabachnik-Fields reaction) for the synthesis of alpha-aminophosphonates catalyzed by magnesium perchlorate

Commercially available magnesium perchlorate is reported as an extremely efficient catalyst for the synthesis of alpha-aminophosphonates. A three-component reaction (3-CR) of an amine, an aldehyde or a ketone, and a di-/trialkyl phosphite (Kabachnik-Fields reaction) took place in one pot under solvent-free conditions to afford the corresponding alpha-aminophosphonates in high yields and short times. The use of solvent retards the rate of the reaction and requires a much longer reaction time than that for neat conditions. The reactions involving an aldehyde, an aromatic amine without any electron-withdrawing substituent, and a phosphite are carried out at rt. The reactions involving cyclic ketones, aromatic amines with an electron-withdrawing substituent, and aryl alkyl ketone (e.g., acetophenone) require longer reaction times at rt or heating. Magnesium perchlorate was found to be superior to other metal perchlorates and metal triflates during the reaction of 4-methoxybenzaldehyde, 2,4-dinitroaniline, and dimethyl phosphite. The catalytic activity of various magnesium compounds was influenced by the counteranion, and magnesium perchlorate was found to be the most effective. The reaction was found to be general with di-/trialkyl phosphites and diaryl phosphite. The Mg(ClO4)2-catalyzed alpha-aminophosphonate synthesis in the present study perhaps represents a true three-component reaction as no intermediate formation of either an imine or alpha-hydroxy phosphonate was observed that indicated the simultaneous involvement of the carbonyl compound, the amine, and the phosphite in the transition state.     

Reaction of N-Phtalylamino Acid Chlorides with Trialkyl Phosphites

Abstract

Reaction of N-blocked amino acid chlorides with trialkyl phosphites is a first step in the synthesis of 2-amino-l-hydroxyalkylphosphonates. Quite surprisingly a very purl trialkyl phosphite is required m order to obtain the desired N-blocked 2-amino-1-oxoalkylphosphonate. Thus, the use of commercially rvailrble phosphites prolongation of the reaction time, or attempts for chromatographic purification of the formed oxophosphonate resulted m quite complicated mixture of products. We haw found that these products arise as a consequence of rearrangements of 1oxo-2. phtalylnmmoalLylphosphonates in a series of reactions which are promoted by that presence of dialkyl phosphite (standard impurity present m commercially availablt trialkyl phosphites) in the reaction medium.     

Fluorine-induced chemiluminescence detection of phosphine,alkyl phosphines and monophosphinate esters

Summary Phosphine, alkylated phosphines and monophosphinate esters are detected with high sensitivity in capillary gas chromatography (GC) by their chemiluminescent reactions with molecular fluorine. Detection limits are estimated to be 1.3 pg, 0.5 pg, 8 pg, and 17 pg for phosphine, trimethyl phosphine, trimethyl phosphinate ester, and triethyl phosphine, respectively. As found earlier with alkylated sulfur, selenium and tellurium compounds, the detector exhibits a linear response. For triethyl phosphine, a linear range of greater than three orders of magnitude was demonstrated. Emission spectra were obtained for the trimethyl phosphine and triethyl phosphine systems. Chemiluminescence emitters include electronically excited HCF, vibrationally excited HF, and an unknown species in the trimethyl phosphine system. Banded emission from vibrationally excited HF and a broad continuum were observed for both trimethyl phosphine and triethyl phosphine; however, HCF emission was observed only for TMP. Under the conditions employed, the principal emitter is HCF for trimethyl phosphine and HF and the unknown emitter for triethyl phosphine. This detector may have important applications in investigations of the biogeochemical cycling of phosphorus.     

Synthesis of Tetrazoloquinoline‐Based Mono‐ and Bisphosphonate Esters as Potent Anti‐Inflammatory Agents

Several new α‐alkoxy‐ and α‐hydroxyphosphonate derivatives of tetrazole‐quinolines were synthesized from the reaction of 2‐azidoquinolines 3‐carboxaldehyde 1a,b with trialkyl phosphites and dialkyl phosphites. On the other hand, azaphospholes 12a,b were obtained by treating 1a,b with tris(dimethylamino)phosphine. Furthermore, Perkin‐type condensation of 1a,b and tetraethyl methylenebisphosphonate provided the corresponding tetrazoloquinoline‐based bisphosphonate esters 14a,b . Based on the prediction results (PASS program), the anti‐inflammatory activity of the prepared compounds was determined in vivo by the acute carrageenin‐induced paw edema in rats. Many of the new compounds exhibit considerable anti‐inflammatory properties at a dose of 50 mg/kg body weight. Especially 14a and 14b revealed remarkable activities compared with indomethacin, which was used as a reference standard in this study.     

FACTORS IN THE CONTROL OF PRODUCT COMPOSITION IN THE REACTIONS OF TRIALKYL PHOSPHITES WITH α-HALOGENOACETOPHENONES IN ALCOHOLIC MEDIA

Abstract

α-Hydroxyphosphonates are formed, in addition to vinyl phosphates and dehalogenated ketones, in the reactions of trimethyl phosphite (in methanol) or triethyl phosphite (in ethanol) with variously substituted α-chloro, α-bromo, and α,α-dichloro-acetophenones. Tri-isopropyl phosphite in propan-2-ol gives only the vinyl phosphate. Ketophosphonates are not detectable amongst the reaction products under the conditions used. Trends in product composition can be correlated with the leaving ability of halogen, substituent effects, structure of the phosphite, and reaction temperature. Additional products are obtained in the reactions of trimethyl phosphite in methanol with 4-nitro-α-chloroacetophenone, which gives the dehalogenated hydroxyphosphonate, and with the α,α-dichloroacetophenones which undergo monodehalogenation. Twenty three new α-hydroxyphosphonates are reported.     

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.     

Derivate des Phosphorsäure-o-phenylenesters. 32. Reaktion von Tris(dimethylamino)phosphin mit Pv-Halogeniden

Derivatives of o-Phenylene Phosphate. 32. Reaction of Tris(dimethylamino)phosphine with Phosphorus(V) Halides The reactions of the Tris(dimethylamino)phosphine with P^v Halides give both the products of the substitution reaction and the products of the redox reaction.