- Nucleoside H-phosphonates. 18. Synthesis of unprotected nucleoside 5'- H-phosphonates and nucleoside 5'-H-phosphonothioates and their conversion into the 5'-phosphorothioate and 5'-phosphorodithioate monoesters
-
A simple and efficient protocol for the preparation of unprotected nucleoside 5'-H-phosphonates and nucleoside 5'-H-phosphonothioates via a one- step deprotection of suitable precursors with methylamine has been developed. The synthetic utility of the unprotected nucleotide derivatives was demonstrated by converting them under mild conditions to the corresponding nucleoside 5'-phosphorothioate and nucleoside 5'-phosphorodithioate monoesters. Factors affecting oxidation of H-phosphonate, H-phosphonothioate, and phosphite derivatives with elemental sulfur are also discussed.
- Jankowska, Jadwiga,Sobkowska, Anna,Cieslak, Jacek,Sobkowski, Michal,Kraszewski, Adam,Stawinski, Jacek,Shugar, David
-
-
Read Online
- A short, novel, and cheaper procedure for oligonucleotide synthesis using automated solid phase synthesizer
-
Dimethylthiuram disulfide (DTD) has been developed as an efficient thiolation reagent during automated synthesis of oligonucleotides using phosphoramidite chemistry. Simultaneous thiolation and capping was accomplished by mixing DTD with capping solution B, which saved 20% of solvent consumption and compressed the four-step synthesis cycle to three. Large-scale (1 mmol) synthesis of phosphorothioate oligonucleotides has been demonstrated with excellent yield and purity.
- Song, Quanlai,Wang, Zhiwei,Sanghvi, Yogesh S.
-
-
Read Online
- Photochemical Conversion of 2-Thioxo-1,3-dithioles into Tetrathiafulvalenes
-
Photochemical reactions of 4,5-diphenyl-2-thioxo-1,3-dithiole in the presence of an electron donor produce tetraphenyltetrathiafulvalene.
- Tsujimoto, Kazuo,Okeda, Yukihiro,Ohashi, Mamoru
-
-
Read Online
- The study of the reaction between thiophosphoryl esters and boron tribromide. The synthesis of oxathiaphosphaboretanes
-
Reactions between three thiophosphoryl esters and boron tribromide are reported. O,O,O-triethyl phosphorothionate (1) and O,O-diethyl methanephosphonothionate (5) gave substituted oxathiaphosphaboretanes 4 and 7 respectively. O-methyl diphenyl-phosphinothionate (9) led to the complex 11 and the corresponding oxathiaphosphaboretane 12. In order to establish the mechanism, reactions were monitored by the multinuclear NMR spectroscopy.
- Lewkowski, Jaroslaw,Mortier, Jacques,Vaultier, Michel
-
-
Read Online
- REACTIONS OF TRIORGANOSILYLSULFENYL HALIDES WITH SOME NUCLEOPHILES
-
The reaction of triorganosilylsulfenyl halides R3SiSX (R=Ph, Et; X=Cl, Br) with carbon-carbon double bonds, trialkyl phosphites, and organometallic reagents have been studied.With the first two nucleophiles the course of the reactions differed from that with organosulfenyl chlorides because of nucleophilic attack of halide ion on silyl group.
- Kowalski, J.,Chojnowski, J.,Michalski, J.
-
-
Read Online
- 1,2,4-Dithiazole-5-ones and 5-thiones as efficient sulfurizing agents of phosphorus(iii) compounds - A kinetic comparative study
-
The sulfurization efficiency of 25 3-substituted-1,2,4-dithiazole-5-ones and 5-thiones towards triphenyl phosphite in acetonitrile, DCM, THF and toluene at 25 °C was evaluated. All the 1,2,4-dithiazoles are much better sulfurizing reagents than commercially available agents (PADS, TETD, Beaucage's reagent). The most efficient sulfurizing agents in all solvents are 3-phenoxy (4), 3-phenylthio (5) and 3-ethoxy-1,2,4-dithiazole-5-one (1) whose reactivity is at least two orders of magnitude higher than that of other 1,2,4-dithiazoles. Contrary to a previous report, the sulfurization with 1 does not yield carbonylsulfide and ethyl cyanate as the additional reaction products but unstable ethoxythiocarbonyl isocyanate which has been trapped with 4-methoxyaniline. Similar trapping experiments have proven that the site of attack is at the sulfur adjacent to the CO group for compounds 4 and 5. The reaction pathway involves rate-limiting initial nucleophilic attack of the phosphorus at sulfur followed by decomposition of the phosphonium intermediate to the corresponding phosphorothioate and isocyanate/isothiocyanate species. The existence of the phosphonium intermediate during sulfurization of triphenyl phosphine with 3-phenyl-1,2,4-dithiazole-5-thione (7a) was proven using kinetic studies. From the Hammett and Bronsted correlations and from other kinetic measurements it was concluded that the transition-state structure is almost apolar for the most reactive 1,2,4-dithiazoles whereas a polar structure resembling a zwitter-ionic intermediate may be more appropriate for the least reactive 1,2,4-dithiazoles. The extent of P-S bond formation and S-S bond cleavage is very similar in all reaction series but it gradually decreases with the reactivity of the 1,2,4-dithiazole derivatives.
- Ponomarov, Oleksandr,Laws, Andrew P.,Hanusek, Ji?í
-
supporting information
p. 8868 - 8876
(2013/01/15)
-
- On the sulfurization of h-phosphonate diesters and phosphite triesters using elemental sulfur
-
Sulfurization of tetracoordinate and tricoordinate P(III) derivatives, namely, H-phosphonate diesters, H-phosphonothioate diesters, and phosphite triesters with elemental sulfur under various experimental conditions, was investigated.
- Wallin, Richard,Kalek, Marcin,Bartoszewicz, Agnieszka,Thelin, Mats,Stawinski, Jacek
-
scheme or table
p. 908 - 916
(2009/12/07)
-
- Alkali metal ion catalysis and inhibition in nucleophilic displacement reactions at phosphorus centers: Ethyl and methyl paraoxon and ethyl and methyl parathion
-
(Chemical Equation Presented) We report on the ethanolysis of the P=O and P=S compounds ethyl and methyl paraoxon (1a and 1b) and ethyl and methyl parathion (2a and 2b). Plots of spectrophotometrically measured rate constants, kobsd versus [MOEt], the alkali ethoxide concentration, show distinct upward and downward curvatures, pointing to the importance of ion-pairing phenomena and a differential reactivity of free ions and ion pairs. Three types of reactivity and selectivity patterns have been discerned: (1) For the P=O compounds 1a and 1b, LiOEt > NaOEt > KOEt > EtO-; (2) for the P=S compound 2a, KOEt > EtO- > NaOEt > LiOEt; (3) for P=S, 2b, 18C6-crown-complexed KOEt > KOEt = EtO- > NaOEt > LiOEt. These selectivity patterns are characteristic of both catalysis and inhibition by alkali-metal cations depending on the nature of the electrophilic center, P=O vs P=S, and the metal cation. Ground-state (GS) vs transition-state (TS) stabilization energies shed light on the catalytic and inhibitory tendencies. The unprecedented catalytic behavior of crowned-K+ for the reaction of 2b is noteworthy. Modeling reveals an extreme steric interaction for the reaction of 2a with crowned-K+, which is responsible for the absence of catalysis in this system. Overall, P=O exhibits greater reactivity than P=S, increasing from 50- to 60-fold with free EtO- and up to 2000-fold with LiOEt, reflecting an intrinsic P=O vs P=S reactivity difference (thio effect). The origin of reactivity and selectivity differences in these systems is discussed on the basis of competing electrostatic effects and solvational requirements as function of anionic electric field strength and cation size (Eisenman's theory).
- Um, Ik-Hwan,Shin, Young-Hee,Lee, Seung-Eun,Yang, Kiyull,Buncel, Erwin
-
p. 923 - 930
(2008/09/18)
-
- REACTIONS OF GROUP 16 ELEMENTS
-
Reactions of Group 16 elements involving the addition of atoms such as sulfur, selenium or tellurium to organic or inorganic molecules comprising use of an ionic liquid as a reaction medium.
- -
-
Page/Page column 29-30
(2008/06/13)
-
- 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 ρ-values for the sulfurisation of substituted triphenyl phosphines and triphenyl phosphites in acetonitrile are ~ -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 ΔS ≠ and ρ 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. The Royal Society of Chemistry 2007.
- Hanusek, Jiri,Russell, Mark A.,Laws, Andrew P.,Jansa, Petr,Atherton, John H.,Fettes, Kevin,Page, Michael I.
-
p. 478 - 484
(2008/03/27)
-
- Aminoparathion: A highly reactive metabolite of parathion. 1. Reactions with polyphenols and polyphenol oxidase
-
Spiking of tomato and apple fruits with parathion at different levels of about 1-4 mg/kg irradiation and under simulated sunlight conditions resulted in nearly complete photodegradation within 13 h, but extractable parathion degradation products could not be found in any case. However, after irradiation of an unrealistically spiked apple (134 mg/kg) different photoproducts including aminoparathion (AP) were detectable by HPLC, proving that the hitherto postulated photochemistry of parathion indeed takes place in the fruit cuticle environment. Besides the photoreduction pathway it was shown for the first time that AP is also easily formed by reduction of the primary photoproduct nitrosoparathion with thiols (cysteine, glutathione), while ascorbic acid only leaves hydroxylaminoparathion. In the presence of polyphenols, AP was effectively bound to quinone intermediates formed by both silver oxide and polyphenol oxidases. For pyrocatechol, a disubstituted o-quinone derivative could be isolated as a dark red addition product and structurally be elucidated. However, in the presence of caffeic acid, catechol, naringin, and quercetin, respectively, insoluble dark colored polymers precipitated within 48 h, while in the supernatants AP was not detectable any more. Polymerbound and nonextractable AP was proven by transesterification with sodium ethoxide releasing O,O,O-triethyl thiophosphate which was determined by GC. Additionally, AP itself was a substrate for polyphenol oxidases, resulting in a quinone imine intermediate which in turn reacted with excessive AP yielding deep red colored di- and trimerization products.
- Rung, Bruno,Schwack, Wolfgang
-
p. 9140 - 9145
(2007/10/03)
-
- Significant and differential acceleration of dephosphorylation of the insecticides, paraoxon and parathion, caused by alkali metal ethoxides.
-
In the reaction of paraoxon with alkali metal ethoxides, ion-paired EtO-M+ species are more reactive than the dissociated EtO- with the reactivity order EtO-Li+ EtO-Na+ > EtO-K+ > EtO-, while in the reaction of parathion, the reactivity follows the order
- Um, Ik-Hwan,Jeon, Sang-Eun,Baek, Mi-Hwa,Park, Hye-Ran
-
p. 3016 - 3017
(2007/10/03)
-
- Reactivity of X3P compounds with elemental sulfur, carbon disulfide or both, to yield X3PS, X3RCS2 or X3P.Sn.CS2 adducts
-
Kinetic constants k2 have been obtained for the reaction of sulfur with 25 PIII compounds in toluene or hexane. In the series PhnMe3-nP (n = 1-3) or PhnBu3-nP (n = 0-3), log k2 decreases linearly with Σχi (χi=Tolman's electronic parameter of each ligand on P), taken as a gauge for the donor strength of P. Dramatic deviations from additivity are observed for the series PhnP(OEt)3-n, PhnP(OEt)3-n, and BunP(OEt)3-n(n = 0-3); the deviation is smaller for PhnPCl3-n, and even smaller for PhnP(NEt2)3-n . The results are discussed in terms of P-coordination (PIV vs. PV), stability and geometry of the intermediate X3P.S8 or of the transition state leading to this adduct, emphasis being laid on the donor/acceptor character of the P site. A similar dependence on X governs the reactivity of X3P with S8, CS2 or both, to give X3PS, X3P.CS2 (binary red adduct) or X3P.Sn.CS2 (ternary yellow adduct) respectively; an explanation for this parallelism is proposed.
- Demarcq, Michel C.
-
p. 307 - 320
(2007/10/03)
-
- Rhenium catalyzed sulfurization of phosphorus(III) compounds with thiiranes: New reagents for phosphorothioate ester synthesis
-
A new method for the mild sulfurization of phosphorus(III) compounds with thiiranes catalyzed by ReOCl3(PPh3)2 (I) or ReOCl3(SMe2)OPPh3) (II) is reported. The novel catalytic sulfur transfer reactions are rapid and occur efficiently under ambient conditions in organic solvents. This methodology enabled propylene sulfide to be used as a sulfurizing agent for the synthesis of a protected nucleotide phosphorothioate ester.
- Arterburn, Jeffrey B.,Perry, Marc C.
-
p. 7701 - 7704
(2007/10/03)
-
- Bisphosphoryl hydrazines and their use as pesticides
-
This invention relates to bisphosphoryl hydrazine compounds and to compositions thereof which are useful as pesticides. The compounds of this invention are effective against soil insects, especially the corn rootworm.
- -
-
-
- Dithiopyrophosphates and their use as pesticides
-
Dithiopyrophosphates and compositions containing dithiopyrophosphates are useful as pesticides, particularaly against soil insects such as corn rootworm.
- -
-
-
- STEREOELECTRONIC EFFECTS IN THE HYDROLYSIS OF PHOSPHONIUM IONS FROM ACYCLIC AND BICYCLIC PHOSPHOROTHIONATES
-
The alkaline hydrolysis of the bicyclic phosphonium ion 1-methyl-3,5,8-trioxabicyclo-octane-4-methylthiophosphonium ion 1 proceeds mainly with P-O bond cleavage as shown by hydrolysis in 18O labeled water to form the cyclic epimers cis- and trans-2-methylmercapto-2-oxo-5-hydroxymethyl-1,3,2-dioxaphosphorinane (2/3) in addition to the bicyclic phosphate, 1-methyl-4-phospha-3,5,8-trioxabicyclooctane-4-oxide, 4.The trans epimer 3 is formed after pseudorotation of the triagonal bipyramid (tbp) intermediate and is the predominant initial product.This could be explained by deprotonation of the initial neutral tbp intermediate 5 followed by fast pseudorotation to give the more stable anionic tbp 5'in which the negatively charged oxygen is placed in the equatorial position of the intermediate.In contrast, the acyclic analogue triethoxy(methylthio)phosphonium ion undergoes alkaline hydrolysis with 100percent P-S bond cleavage.It is very unusual to observe P-O bond cleavage competitive with P-S bond cleavage as we have demonstrated for the hydrolysis of the bicyclic thiophosphonium ion, 1.These results are supportive of the stereoelectronic effect hypothesis.
- Farschtschi, Nasser,Gorenstein, David G.,Fanni, Tahsin,Taira, Kazunari
-
-
- An efficient approach toward the synthesis of phosphorothioate diesters via the Schonberg reaction
-
Easily accessible phenacetyl or benzoyl disulfide proved to be very conventional ragents for a rapid P-sulfurization of phosphite-triesters and H-phosphonate diesters, respectively.
- Kamer,Roelen,Van den Elst,Van der Marel,Van Boom
-
p. 6757 - 6760
(2007/10/02)
-
- Reactions of Alcohols with O,O-Diethylphosphorothioic and O,O-Diethylphosphorodithioic Acid in the Presence of Triphenylphosphine and Diethyl Azodicarboxylate, II. 31P-N.M.R. Studies
-
Low temperature 31P-n.m.r. studies of the reaction of O,O-diethylphosphorothioic acid with triphenylphosphine and diethyl azodicarboxylate revealed that, at low temperatures, the only intermediate is the protonated betaine, even in the presence of neopentyl alcohol.Above 0 deg C this species reacts with neopentyl alcohol to produce the neopentoxytriphenylphosphonium salt which decomposes to isomeric diethyl neopentyl phosphorothioates and triphenylphosphine oxide, at elevated temperatures.The reaction of ethanol with O,O-diethylphosphorodithioic acid leads mainly to O,O,S-triethyl phosphorodithioate and triphenylphosphine oxide.In addition, a small amount of O,O,O-triethylphosphorothionate and triphenylphosphine sulfide were detected.The mechanism of these reactions is suggested.
- Mlotkowska, B.
-
p. 380 - 386
(2007/10/02)
-
- Kinetics and mechanism of the reaction of trico-ordinate phosphorus ompounds with octasulphur
-
Kinetic data and activation parameters are reported for the reactions of a series of phosphites, arylphosphonites, diarylphosphinites, and triarylphosphines with octasulphur (S8) in toluene as solvent.For the phosphites the data are explained in terms of changes in p-character of the Ione-pair orbital on phosphorus and inductive electron donation by the alkyl groups.The rates of reaction of series of arylphosphonites, diarylphosphonites, and triarylphosphones correlate with the Hammett ? constants to give ? values of -3.0, -3.0, and -2.5, respactively, and the results are discussed in terms of the Reactivity-Selectivity Principle and the biphilic mechanism or insertion of trico-ordinate phosphorus into ?-bonds.
- Lloyd, John R.,Lowther, Nicholas,Zsabo, G.,Hall, C. Dennis
-
p. 1813 - 1818
(2007/10/02)
-
- Reaction of Carbodiimides with Phosphorothioic, Phosphorodithioic, and Phosphoroselenoic Acids: Products, Intermediates, and Steps
-
The reaction of the title acids with dicyclohexylcarbodiimide (DDC) used in a 2:1 ratio was found to give a complex mixture of products consisting of thio(seleno)pyrophosphates, thiolo(selenolo)phosphates, thiono(selenono)phosphates, dicyclohexylthiourea (DCTU), and a polymeric alkyl metaphosphate.When both reaction components are mixed in a 1:1 ratio, N-phosphoryl-N,N'-dicyclohexylthio(seleno)ureas (B) were formed.The formation of equimolar adducts (B) was also observed with other dialkyl- and diarylcarbodiimides.The spectral properties (especially the value of 3JP-H) and reactivity of these adducts are strongly dependent on their conformation.The distinct conformational differences between the adducts B derived from DCC and diisopropylcarbodiimide (DiPC) and those obtained from dibenzylcarbodiimide (DBC) and diarylcarbodiimides were revealed by X-ray analysis of the selected N-phosphorylthioureas.By means of low temperature FT 31P NMR spectra it was demonstrated that the adducts (B) arise from the first formed unstable S(Se)-phosphorylisothio(seleno)ureas (A) as a result of S(Se)->N-phosphoryl migration.The differences in ability of the phosphoryl group to undergo S(Se)->N and O->N 1,3-shifts are briefly described.N-Phosphorylthio(seleno)ureas (B) obtained from DCC and DiPC, in contrast to those prepared from DBC and diarylcarbodiimides, reacted with a second thio(seleno)acid molecule.Crossover experiments and the use of O,O-diethyl phosphorothioate containing 35S-labeled sulfur showed that the adducts (B) are in equilibrium with their unstable isomers (A), the latter being active phosphorylating agents.The formation of the final reaction products was rationalized in terms of the threedirectional attack of the thioacid anion at the phosphorus, alkoxy carbon, and central carbon atoms of the protonated adduct (A).
- Mikolajczyk, Marian,Kielbasinski, Piotr,Basinski, Wlodzimierz
-
p. 899 - 908
(2007/10/02)
-
- O,O-Dialkyl Thiophosphoro- and O-Alkyl Phenylthiophosphono-cyanidates: Synthesis and Reactions
-
The title compounds (2a-d) have been prepared by the reactions of the corresponding chloridates (1a-d) with potassium cyanide in a two-phase system (dichloromethane-water) in the presence of cetyltrimethylammonium bromide.An unexpected facile conversion of these cyanidates (2a-d) into O,O,O-trialkyl thiophosphates (5a) or O,O-dialkyl phenyl thiophosphonates (5b) has been observed in the presence of aqueous alcoholic potassium hydroxide.
- Das, Sushanta K.,Balasubrahmanyam, S. N.
-
p. 254 - 256
(2007/10/02)
-
- Dialkyl (3-Aryl-1,2,4-oxadiazol-5-yl)phosphonates: Synthesis and Thermal Behavior - Evidence for Monomeric Alkyl Metaphosphate
-
Dialkyl (3-aryl-1,2,4-oxadiazol-5-yl)phosphonates 6a-h have been obtained by 1,3-dipolar cycloaddition of arenenitrile oxides 5a-f to dialkyl phosphorocyanidates (4a and 4b) in yields ranging between 30percent and 58percent.A standardized method for obtaining cyanidates 4a and 4b has been established.The diethyl thiophosphorocyanidate (4c) is less reactive than 4a and 4b, only the 3-(4'-nitrophenyl) derivative 6i being obtainable.While the IR and NMR spectra of 6a-6i were unexceptional, their UV spectra showed evidence of conjugative interaction in high degrees between the phosphonate and heterocyclic moieties as well as a varying conjugative interaction between the heterocyclic and aryl moieties.The oxadiazoles 6a-h are thermally labile and yield trialkyl phosphates 7 as the only identifiable products.A mechanism based on the intermediacy of monomeric alkyl metaphosphate 11 in the formation of trialkyl phosphate was postulated, and supportive evidence in the form of trapping the metaphosphate with acetophenone has been obtained.
- Das, Sushanta K.,Balasubrahmanyam, S. N.
-
p. 4232 - 4236
(2007/10/02)
-
- Phosphororganische Verbindungen 100. Thiophosphylverbindungen Durch P=O/P=S-Austausch
-
Phosphinic-acid-, phosphonic-acid- and phosphoric-acid-derivatives react in high yields with Lawesson's reagent to form the corresponding thiophosphyl-compounds.
- Horner, L.,Lindel, H.
-
p. 259 - 262
(2007/10/02)
-
- Reactions of Group V Metal Compounds with Sulfur Trioxide
-
Trialkylphosphines react with equimolar amounts of sulfuric trioxide to form the 1:1 adducts R3P(1+)-SO3(1-).Trialkylarsines and -stibines undergo sulfur trioxide insertion reaction across the metal-carbon bond to give the trisulfonates of the metal M(OSO2R)3 (M=As,Sb).The reactions of trialkyl phosphites, with sulfur trioxide yield trialkyl phosphonates, trialkyl thiophosates, dialkyl alkylphosphonates, dialkyl sulfates, and polymers which contain phosphorus atoms.The reactions of trialkoxyarsines and -stibines result in the insertion of sulfur trioxide across the metal-oxygen bond to form the alkoxymetal alkylsulfates (RO)3-nM(OSO3R)n (M=As,Sb; n=1,2,3) depending on the stoichiometric ratios of the reagents used.Pyrolysis of the metal sulfates gives dialkyl sulfates and undistillable residues containing the metals.
- Ando, Fumio,Koketsu, Jugo,Ishii, Yoshio
-
p. 3495 - 3499
(2007/10/02)
-