Direct mass spectrometric analysis of the 18O/16O ratio in sulfur-containing organophosphorus compounds

High precision measurements of the ¹⁸O/¹⁶O ratio in bis-(5,5-dimethyl-2-oxo-1,3,2-P-dioxaphosphorinanyl)-sulfide and P¹-oxo-P²-thiono(5,5-dimethl-1,3,2-dioxaphosphorinanyl)oxidee have been carrid out using a Finnigan 4000 mass spectrometer.     

Design,synthesis and herbicidal activity of novel cyclic phosphonates with diaryl ethers containing pyrimidine

Abstract

Thirteen novel cyclic phosphates were rationally designed and synthesized by introducing diary ethers containing pyrimidine. All the target compounds were characterized by ¹H, ¹³C, ³¹P NMR and HRMS. The test of herbicidal activity indicated that most of the compounds showed good herbicidal activities against Amaranthus retroflexus. The compounds IA-2 (1-(5,5-dimethyl-2-oxido-1,3,2-dioxaphosphinan-2-yl)propyl-2-((4,6-dimethoxypyrimidin-2-yl)oxy)benzoate) and IA-3 ((5,5-dimethyl-2-oxido-1,3,2-dioxaphosphinan-2-yl)(phenyl)methyl-2-((4,6-dimethoxypyrimidin-2-yl)oxy)benzoate) exhibited remarkable post-emergency herbicidal activity against the tested monocotyledonous weed at the dosage of 112.5?g ai/ha.     

31P High Resolution Solid State NMR Spectroscopy as a Tool for Structural Studies of Organothiophosporyl Compounds

Abstract

Employing 1,6-anhydro-2-0-(tosyl)-4-S-(5,5-dimethyl-2-tioxa-1,3,2-dioxaphosphorinan-2-yl) β-D-glucopyranose 1, bis-imidazole 5,5-dimethyl-1,3,2-dioxaphosphorinan-2-tioxa-2-hydroxy complex II and bis (organothiophosphoryl) dichalcognides III as models this report presents power of ¹³C and ³¹P CP/MAS experiment in structural studies organothiophosphoryl compounds [1,2,3].     

Synthesis and crystal structure of optically active 2-[benzyl(phenyl)amino]ethyl 5-(5,5-dimethyl-2-oxo-1,3,2-dioxaphosphorinan-2-yl)-1,4-dihydro-2,6-dim ethyl-4-(3-nitrophenyl)-3-pyridinecarboxylate (NZ-105).

(S)-2-[Benzyl(phenyl)amino]ethyl 5-(5,5-dimethyl-2-oxo-1,3,2-dioxaphosphorinan-2-yl)-1,4-dihydro-2, 6-dimethyl-4-(3-nitrophenyl)-3-pyridinecarboxylate ((S)-NZ-105) and R isomer were synthesized through the fractional crystallization of (S)-2-Methoxy-2-phenylethyl 5-(5,5-dimethyl-2-oxo-1,3,2-dioxaphosphorinan-2-yl)-1,4-dihydro-2, 6-dimethyl-4-(3-nitrophenyl)-3-pyridinecarboxylate. Calcium antagonism activity was found to reside in the S isomer from single crystal X-ray diffraction analysis.     

Spectroscopic study of the conformation of 1,3,2-dioxaphosphorinanes with a P=S bond

5,5- Dimethyl-2-thio-2-phenoxy- and 5,5-dimethyl-2-thio-2-ethoxy-1,3,2-dioxaphosphorinanes exist in the liquid state and in solution in a three-component equilibrium featuring two chair forms with equatorial orientation of the P=S bond differing in the orientation of the OPh or OEt groups and a chair form with an axial P=S bond. The P=S bond in 4-methyl-2-thio-2-phenoxy-1,3,2-dioxaphosphorinane occupies the equatorial position.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 479–482, February, 1990.     

Cyclic organophosphorus compounds: XVII—the mass spectra of some 5,5-dimethyl-perhydro-1,3,2-oxazaphosph(v)orines

The electron impact mass spectra of six 5,5-dimethyl and eleven 3,5,5-trimethyl-perhydro-1,3,2-oxazaphosphorine 2-oxides and 2-sulphides are reported and compared with those of analogous 5,5-dimethyl-1,3,2-dioxaphosph(v) orinans. Compounds of the 3,5,5-trimethyl series produce an important ion at m/z 44 which clearly distinguishes them from the 5,5-dimethyl series. The 2-sulphides are characterized by loss of thiol radical rather than of sulphur; in the case of 2-cyclohexylamino-3,5,5-trimethyl-perhydro-1,3,2-oxazaphosphorine 2-sulphide at least, the thiol hydrogen is derived from the oxazaphosphorine ring NCH₂ group. Fission of the oxazaphosphorine ring occurs largely, but apparently not exclusively, at the P? O? C linkages.     

Phosphorinane and Enol Rings in One Molecule. Evidence for Reciprocal Stabilization of Half-Chair Conformations

Abstract.

The X-ray crystal structure of 2-(2′,4′-dioxo-3′-pentyl)-5,5-dimethyl-2-oxo-1,3,2-dioxaphosphorinane (2) reveals significant half-chair distortion of the axially oriented cisenol ring. The molecule also undergoes in-plane deformations. R(O...O) = 2.410 Å in the enol moiety indicates a very strong hydrogen bonding. The enol content, δ_OH and thermodynamic parameters for the axial-equatorial conformational and keto-enol equilibriums were obtained from ¹H, ³¹P NMR and IR measurements in comparison with the planar 4,6-dimethyl isomer (1) containing equatorially oriented enol ring. The X-ray single crystal structure of 5,5-dimethyl-2-(methoxycarbonyl-3′-oxo-2′-butyl)-2-oxo-1,3,2-dioxaphosphorinane (3) reveals the unusual half-chair conformation of the dioxaphosphorinane cycle disposed a trans-enol ring substituent. ¹H, ³¹P NMR and IR solution data support the same structure displays a strong conformational preference while the minor forms are chair conformers with an axial or equatorial cis-enol ring.     

The preparation of some cyclic phosphonates and their use in olefin synthesis

The preparation and the use in olefin synthesis of two 5-membered cyclic phosphonates, 2-carbethoxy-methyl 4,5-dimethyle-2-oxo-1,3,2-dioxaphospholane (4b) and 2-cyanomethyl-4,5-dimethyl-2-oxo-1,3,2-diox-aphospholane (4c) and the 6-membered phosphonates, 2-carbalkoxymethyl-5,5-dimethyl-2-oxo-1,3,2-diox-aphosphorinanes (5a and 5b) and 2-cyanomethyl-5,5-dimethyl-2-oxo-1,3,2-dioxaphosphorinane (5c) are described. Reactions of 4b with aromatic and aliphatic aldehydes lead to preferential formation of cis-olefins. Reactions of the other cyclic phosphonates with aldehydes lead to various mixtures of cis and trans olefins.     

REACTIONS OF SULFUR DIOXIDE WITH AMINOPHOSPHINES

Abstract

The reactions of SO₂ with tris-dimethylaminophosphine, bis-dimethylaminofluorophosphine, bis-dimethylaminochlorophosphine, dimethylaminodifluorophosphine, dimethylaminodichlorophosphine, 1,3-dimethyl-2-fluoro-1,3,2-diazaphospholidine and 1,3-dimethyl-2-chloro-1,3,2-diazaphospholidine have been investigated. The complex reactions are dominated by facile oxidation of the respective phosphine to phosphoryl and thiophosphoryl derivatives. The new heterocyclic phosphines CH₃ NCH₂CH₂N(CH₃)P(O)F and CH₃ NCH₂CH₂N(CH₃)P(S)F have been isolated and characterized by NMR, infrared, and mass spectrometry.     

Asymmetric Cyclic Phosphorothonamides Containing Substituted Pyridine

In order to find high-acitivity and low-toxicity pesticidal lead compounds, a type of novel, asymmetric cyclic phosphorothonamides containing substituted pyridine were synthesized via the condensation reactions of 2-chloro-4-substitutedphenyl-5,5-dimethyl-1,3,2-dioxaphosphinane 2-sulfide with 3-aminomethylpyridine. The cis and trans isomers of the products were isolated by column chromatography on silica gel. The structures of the products were characterized by ¹ H NMR, ³¹ P NMR, MS, and elemental analyses. The configuration of 3a was determined by X-ray diffraction analysis. The results of the preliminary bioassay showed that the new compounds possess potential fungicidal activities.     

Synthesis,Crystal Structure,and Flame Retardance of 2-(3-Silatranyl-Propylamino)-4-(2,4-Dichlorophenyl)-5,5-Dimethyl-1,3,2-Dioxaphosphinane-2-Sulfide

Abstract

2-(3-Silatranylpropylamino)-4-(2,4-dichlorophenyl)-5,5-dimethyl-1,3,2-dioxa phosphinane-2-sulfide 4 was synthesized by a nucleophilic substitution reaction of 2-chloro-1,3,2-dioxaphosphinane-2-sulfide 2 with γ-aminopropylsilatrane 3, which was prepared by the cyclization reaction of triethanolamine and γ-aminopropyltriethoxysilane. The structure of the title compound was confirmed by IR, ¹H NMR, ³¹P NMR, EI-MS, and elemental analysis as well as by single crystal X-ray diffraction and its thermal properties were studied by thermogravimetry (TG) and differential scanning calorimetry (DSC). Thermal analysis and preliminary fire retardance testing suggest that compound 4 should function as a good flame retardant.     

13C Kinetic Isotope Effect of the Pudovik Reaction

Abstract

¹³C kinetic isotope effect (KIE) was determined by means of ¹³C NMR for the carbonyl atom in 2-nitrobenzaldehyde in its reaction with 2H-2-oxo-5,5-dimethyl-4-phenyl-1,3,2-dioxaphosphorinane in acetonitrile at 25°C. The observed isotope effect k₁₂/k₁₃ = 1.0238 ± 0.0031 evidences that the formation of the P?C bond in the Pudovik reaction catalyzed by triethylamine is less advanced than the π-bond breakage of the aldehyde carbonyl group.     

Tris-phosphorylated esters of symmetrical and unsymmetrical triols

By reaction of a series of triols and monosaccharides with 5,5-dimethyl-2-chloro-1,3,2-dioxaphosphorinane their tris-phosphorylated derivatives were synthesized, and the simplest chemical transformations of the latter were studied. Structures of the obtained P(V) derivatives were confirmed by ¹H, ¹³C and ³¹P NMR spectroscopy and by the MALDI TOF mass spectrometry and X-ray structural analysis.     

CYCLIC ORGANOPHOSPHORUS COMPOUNDS. PART XVI1. MASS SPECTROMETRIC FRAGMENTATION OF SOME 5,5-DIMETHYL-1,3,2-DIOXAPHOSPHORINAN 2-OXIDES AND 2-SULPHIDES

Abstract

The mass spectra of seventeen 5,5-dimethyl-1,3,2-dioxaphosphorinan 2-oxides and nineteen 5,5-dimethyl-1,3,2-dioxa-phosphorinan 2-sulphides, mostly with amino substituents on phosphorus, have been determined. In some cases, interpretation of the spectra was aided by accurate mass measurements and by the examination of deuterated compounds. For the 2-sulphides, sulphur is lost either as such or as the thiol radical, both processes often being of weak intensity, and the thiol hydrogen appears to be derivable from either a ring methylene group or a C-5 methyl group. Loss of S or HS occurs more strongly for the phosphoramidothionates which, together with the phosphoramidates, also fragment to an important extent in the amido substituent with retention of the dioxaphosphorinan ring; P[sbnd]N bond cleavage is also observed. For the 2-thiones, the ions at m/e 165 (14; R[dbnd]H) and 133 (15; R[dbnd]H) are characteristic.     

5,5-Bis(alkoxy-NNO-azoxy)-1,3,2-dioxathiane 2-oxides. Synthesis and X-ray diffraction study

2,2-Bis(alkoxy-NNO-azoxy)propane-1,3-diols reacted with thionyl chloride to give previously unknown 5,5-bis(methoxy-NNO-azoxy)- and 5,5-bis(ethoxy-NNO-azoxy)-1,3,2-dioxathiane 2-oxides. Replacement of the hydroxy groups by chlorine is a minor reaction path. According to the X-ray diffraction data, the heteroring in the molecule of 5,5-bis(methoxy-NNO-azoxy)-1,3,2-dioxathiane 2-oxide adopts a chair conformation with axial orientation of the S=O bond.     

Conformational analysis of 7-membered dimethyl cyclic sulphites: 2-Oxo-1,3,2-dioxathiepanes and 3-oxo-2,4,3-dioxathiepins

2-Oxo-1,3,2-dioxathiepanes and 3-oxo-2,4,3-dioxathiepins, including two series of three diastereoisomers, were synthesized, isolated by HPLC and characterized by ¹H and ¹³C NMR spectroscopy. Their conformational behaviour was studied using a computer-assisted LIS technique and, for c-4, t-7-dimethyl-2-oxo-1,3,2-dioxathiepane, a 400 MHz spectral analysis. Single twist-chair conformations or an equilibrium between them are the most stable in the dioxathiepane series while chair or twist-boat forms, or both in equilibrium, are favoured in the dioxathiepin series. Conformations and equilibria are detailed, with and without LSR, taking into account ¹H coupling constants and IR S?O stretching frequencies as conformational probes.     

Additionsreaktion von 3-Dimethylamino-2,2-dimethyl-2H-azirin mit Phenylisothiocyanat

Reaction of 3-Dimethylamino-2,2-dimethyl-2H-azirine with Phenyl Isothiocyanate In contrast to the reactions of 3-dimethylamino-2,2-dimethyl-2H-azirine ( 1a ) with various isothiocyanates, leading to thiazoline derivatives, the reaction of 1a with phenyl isothiocyanate at room temperature gives 5,5-dimethyl-3-phenyl-Δ¹-imidazolin-4-dimethyliminium-2-thiolate ( 9 , Scheme 2). The structure of 9 is deduced from spectral data and reactions of this zwitterionic compound (Schemes 2 and 4).     

Conformational analysis of 1,3,2-dioxathiane and its oxides

Computer simulation of the routes of conformational isomerization of 1,3,2-dioxathiane and its Soxides by nonempirical quantum-chemical method RHF/6-31G(d) revealed the main and local minima and transition states of this process. It was shown that the barrier of ring inversion is reduced in going from 1,3,2-dioxathiane to its oxides. The established ΔG ⁰ (300 K) value of S=O group in cyclic sulfite (−15.0 kJ mol⁻¹) is in good agreement with the experimental data.     

Mechanism and stereochemistry of diphosphate formation from dioxaphosphorinanes: a critical reassessment.

The mechanism of diphosphate formation from (R)-2-chloro-2-oxo-5,5-dimethyl-4-(R)-phenyl-1,3,2-dioxaphosphorinane (5a) and 2-hydroxy-2-oxo-5,5-dimethyl-4-(R)-phenyl-1,3,2-dioxaphosphorinane (6) has been investigated. The products formed are the ax-ax diphosphate 7a and the ax-eq diphosphate 7b, with no evidence in the 31P NMR spectrum for pentacoordinate chlorooxyanionic phosphoranes 9. The structure of 7bhas been established unambiguously by NMR spectroscopy, mass spectrometry, and elemental analysis, and the structures of 5a and 7a have been confirmed by X-ray crystallography. The mechanism of the crucial diphosphate-forming reaction has been probed using 18O-labeling studies. The 18O-labeling patterns are consistent with the unsymmetric ax-eq diphosphate 7b arising from selective nucleophilic attack of the axial oxygen of 6 on the chloride 5a with inversion of configuration at phosphorus. The symmetric ax-ax diphosphate 7a can be formed directly, as a result of selective nucleophilic attack of the axial oxygen of 6 on the chloride 5a with retention of configuration, but the majority arises indirectly by isomerization of the ax-eq diphosphate 7b. The isomerization apparently involves intermolecular exchange, with nucleophilic attack of the phosphate anion 6 on the equatorially substituted phosphorus atom of 7b with inversion of configuration at phosphorus.     

Oxydative Derivatisierung von 1,3,2-Dioxaphosphorinanen unter Verwendung von Tetrachlormethan als Oxydans

Oxidative Derivatization of 1,3,2-Dioxaphosphorinanes Using Carbon Tetrachloride as Oxidant 2-Alkoxy- and 2-dialkylamido-1,3,2-dioxaphosphorinanes react with CCl₄ in presence or absence of protic nucleophiles under ring opening forming acyclic derivatives of phosphates. 2-Anilido-1,3,2-dioxaphosphorinane, however, forms 2-amido-2-phenylimido-1,3,2-dioxaphosphorinanes ( 6 ) retaining the heterocyclic ring system. The latter are also obtained in the reaction of 2-dialkylamido-1,3,2-dioxaphosphorinanes with CCl₄ and aniline. 2-Amino-2-oxo-1,3,2-dioxaphosphorinanes ( 8 ) are prepared from 2-hydrido-2-oxo-1,3,2-dioxaphosphorinane ( 7 ) by means of the Atherton-Todd reaction. In combination with the Staudinger reaction the latter yields N(2-oxo-1,3,2-dioxaphosphorinanyl)phosphazenes ( 10 ).