993-43-1Relevant academic research and scientific papers
Mass spectral characterization of the CWC-related isomeric dialkyl alkylphosphonothiolates/alkylphosphonothionates under gas chromatography/mass spectrometry conditions
Karthikraj,Sridhar,Prabhakar,Raju, N. Prasada,Murty,Vairamani
, p. 1461 - 1472 (2013/07/27)
RATIONALE The isomeric dialkyl alkylphosphonothiolates and dialkyl alkylphosphonothionates are listed as scheduled chemicals of the Chemical Weapons Convention (CWC) implemented by the OPCW. The P-S and P-R bond connectivity has to be correctly identified for the verification of the CWC. The present study demonstrates successful identification of the target isomers by selective fragmentation under electron ionization (EI) or chemical ionization (CI) conditions. METHODS All the studied isomeric compounds (27 in total) were synthesized in our laboratory using established methods, then analyzed by EI and CI gas chromatography/mass spectrometry (GC/MS) using an Agilent 6890 gas chromatograph equipped with a HP-5MS capillary column and interfaced to a 5973 N mass-selective detector. The retention index (RI) values of all the compounds were calculated using Van den Dool's formula. GC/MS/MS and GC/HRMS experiments were also performed using a VG-Autospec (magnetic sector) and JEOL-AccuToF (time-of-flight) mass spectrometer, respectively. RESULTS The EI mass spectra of all the compounds had an abundant molecular ion at m/z 182, except in the case of a few selected butyl-substituted compounds, where this ion was of low abundance. The EI fragmentation pathways include α-cleavage, McLafferty rearrangement, McLafferty + 1 rearrangement, O/S-alkyl radical loss, and an alkene loss with a hydrogen shift. The characteristic fragment ions and their relative abundances are significant in elucidating the alkyl group attached to the P/S/O-atoms as well as the P-S/P = S bond connectivity. The EI and CI mass spectra together with RI values enable unambiguous identification of all the studied isomeric compounds. CONCLUSIONS The present study highlights the structural characterization of the isomeric phosphonothiolates and phosphonothionates based on their selective EI fragmentation. The assigned fragmentation pathway helps in the assignment of P-S and P-alkyl connectivity in phosphonothiolates and phosphonothionates, consequently the structure of the unknown compounds. The EI mass spectra (27 compounds) of isomeric compounds are immensely useful in the OPCW official proficiency tests and for off-site analysis. Copyright 2013 John Wiley & Sons, Ltd. Copyright
Microsynthesis and electron ionization mass spectral studies of O(S)-alkyl N,N-dimethyl alkylphosphono(thiolo)thionoamidates for Chemical Weapons Convention verification
Saeidian, Hamdollah,Babri, Mehran,Abdoli, Morteza,Sarabadani, Mansour,Ashrafi, Davood,Naseri, Mohammad Taghi
, p. 2805 - 2814 (2013/01/15)
RATIONALE The availability of mass spectra and interpretation skills are essential for unambiguous identification of the Chemical Weapons Convention (CWC)-related chemicals. The O(S)-alkyl N,N-dimethyl alkylphosphono(thiolo) thionoamidates are included in the list of scheduled CWC-related compounds, but there are very few spectra from these compounds in the literature. This paper examines these spectra and their mass spectral fragmentation routes. METHODS The title chemicals were prepared through microsynthetic protocols and were analyzed using electron ionization mass spectrometry with gas chromatography as a MS-inlet system. Structures of fragments were confirmed using analysis of fragment ions of deuterated analogs, tandem mass spectrometry and density functional theory (DFT) calculations. RESULTS Mass spectrometric studies revealed some interesting fragmentation pathways during the ionization process, such as alkene and amine elimination and McLafferty-type rearrangements. The most important fragmentation route of the chemicals is the thiono-thiolo rearrangement. DFT calculations are used to support MS results and to reveal relative preference formation of fragment ions. The retention indices (RIs) of all the studied compounds are also reported. CONCLUSIONS Mass spectra of the synthesized compounds were investigated with the aim to enrich the Organization for the Prohibition of Chemical Weapons (OPCW) Central Analytical Database (OCAD) which may be used for detection and identification of CWC-related chemicals during on-site inspection and/or off-site analysis such as OPCW proficiency tests. Copyright
Synthesis and chiral recognition ability of O-phenyl ethylphosphonothioic acid with a conformationally flexible phenoxy group for CH/π interaction
Kobayashi, Yuka,Maeda, Jin,Morisawa, Fumi,Saigo, Kazuhiko
, p. 967 - 974 (2007/10/03)
Enantiopure O-phenyl ethylphosphonothioic acid 1 was easily obtained by the enantioseparation of racemic 1, which was prepared from commercially available phosphorothioic trichloride in four steps. Enantiopure 1 was found to show an excellent chiral recognition ability for various 1-arylethylamine derivatives during the diastereomeric salt formation. In particular, enantiopure 1 was able to recognize the chirality of o- and m-substituted 1-arylethylamine derivatives, of which the chirality is generally difficult to establish by conventional resolving agents. X-ray crystallographic analyses of the less-soluble diastereomeric salts revealed that the conformation of the phenoxy group in enantiopure 1 could change in the diastereomeric salt crystals and that the excellent chiral recognition ability of enantiopure 1 resulted from the effective CH/π interaction of the phenoxy phenyl group.
ASYMMETRIC SYNTHESIS OF (Rp)- AND (Sp)-2-ETHYL-, (Rp)-2-PENTYLOXY-, (Sp)-2-PENTYLTHIO- AND (Sp)-2-PENTYLAMINO-4H-1,3,2-BENZODIOXAPHOSPHORIN 2-OXIDES
Wu, Shao-Yong,Casida, John E.
, p. 129 - 138 (2007/10/02)
2-Substituted-4H-1,3,2-benzodioxaphosphorin 2-oxides (2-substituted-BDPOs) are potent and stereoselective inhibitors of neuropathy target esterase (NTE) when the 2-substituent is n-alkyl, n-alkyloxy, n-alkylthio or n-alkylamino with maximum potency for the C7 to C9 analogs.Asymmetric syntheses were developed to assign the absolute configurations of each type of 2-substituted-BDPO. (Sp)-O-Methyl ethylphosphonothioic acid, the chiral starting material for (Rp)- and (Sp)-2-ethyl-BDPOs, was obtained by resolution of the racemate with quinine.It was > 82percent e.e. based on its stereospecific conversion to (Rp)-O-methyl ethylphosphonochloridothionate which was coupled with (Sc)-(-)-α-methylbenzylamine for analysis of the diastereomeric derivative by 1H and 31P NMR and HPLC.The final (Rp)- and (Sp)-2-ethyl compounds were 80 and 82percent e.e., respectively.The starting material for the chiral O-, S- and N-pentyl-BDPOs was (ScRp)-2--4H-1,3,2-benzodioxaphosphorin 2-sulfide which was recrystallized to 100percent d.e. (Rp)-2-Pentyloxy-BDPO (94percent e.e.) was obtained by two reaction sequences involving two or four steps. (Sp)-2-Pentylthio-BDPO (100percent e.e.) and (Sp)-2-pentylamino-BDPO (58 e.e.) were prepared in three- and five-step reactions, respectively.Optical purities were determined by HPLC with a CHIRALCEL OC column.In each asymmetric synthesis, the stereochemical orientation assigned for the substituents on phosphorus was consistent with the chromatographic characteristics on the chiral column. Key words: Asymmetric synthesis; 1.3.2-benzodioxaphosphorin 2-oxide; NTE inhibitors; stereochemistry.
DIE STRUKTUR VON ALKYL- UND ARYLPERTHIOPHOSPHONSAEUREANHYDRIDEN IN LOESUNG
Ohms, Gisela,Treichler, Antje,Grossmann, Gisbert
, p. 95 - 102 (2007/10/02)
The analysis of 1H-, 31P- and 13C-NMR spectra of different alkyl- and arylperthiophosphonic acid anhydrides shows that these compounds prefer a dimeric structure in solution.They exist as 2,4-diorganyl-2,4-dithioxo-1,3,2λ5,4λ5-dithiadiphosphetanes.Most of the perthiophosphonic acid anhydrides form configuration isomers which differ in the position of the thioxo groups relatively to the ring plane.The concentration of the trans-isomer is generally larger than that of the cis-isomer.The ratio of the concentration of both isomers is obviously determined by the polarity of the solvent used.Mixing of solutions of different perthiophosphonic acid anhydrides results in unsymmetrical compounds also existing in cis- and trans-configuration. 31P chemical shifts and geminal P-P coupling constants for symmetrical and unsymmetrical perthiophosphonic acid anhydrides are presented and discussed. - Key words: 31P chemical shifts; P-P coupling constants; perthiophosphonic acid anhydrides; mixed perthiophosphonic acid anhydrides; configuration isomers; 2,4-diorganyl-2,4-dithioxo-1,3,2λ5,4λ5-dithiadiphosphetanes.
Process for preparing alkyl or aryl phosphorus halides and mixed isomers thereof
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, (2008/06/13)
Alkyl or aryl phosphonic or phosphonothioic dihalides and phosphinic or phosphinothioic monohalides are prepared by reacting an alkyl halide or aryl halide respectively with a tri-valent phosphorus compound having at least two halogens attached thereto, and preferably three two halogens such as phosphorus trihalide, in the presence of P4 O10 or P4 S10 under at least autogenous pressure at a temperature of from 200° C. to 450° C. The compounds obtained are useful as constituents in insecticides, fungicides, pharmaceuticals, and as intermediates in preparation of other organophosphorus compounds.
