The Experts below are selected from a list of 261 Experts worldwide ranked by ideXlab platform
Jon T. Njardarson - One of the best experts on this subject based on the ideXlab platform.
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mild stereoselective formation of tri and tetrasubstituted olefins by regioselective ring opening of 1 1 disubstituted vinyl oxiranes with dialkyl Dithiophosphates
Tetrahedron Letters, 2014Co-Authors: Edon Vitaku, Jon T. NjardarsonAbstract:Abstract Presented in this Letter is a mild new method to stereoselectively ring open 1,1-disubstituted vinyl oxiranes using dialkyl dithiophosphate nucleophiles. This new reaction proceeds in toluene at room temperature to afford tri- and tetrasubstituted allylic alcohols with high Z -selectivity. The syn relationship between the alcohol and the newly incorporated dithiophosphate moiety presented an opportunity to evaluate the anionic hopping properties of the ring opening product. Treatment of the ring opening product with base results in a facile phosphate hopping followed by a selective thiolate 3- exo-trig instead of a 5- exo-tet cyclization.
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Z-Selective ring opening of vinyl oxetanes with dialkyl dithiophosphate nucleophiles
Chemical Communications, 2013Co-Authors: Jon T. NjardarsonAbstract:Dialkyl Dithiophosphates selectively ring open vinyl oxetanes in excellent yields under mild reaction conditions to form useful allylic thiophosphate products with high Z-selectivity.
I S Nizamov - One of the best experts on this subject based on the ideXlab platform.
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chiral s stannyl Dithiophosphates and dithiophosphonates on the basis of monoterpenols
Applied Organometallic Chemistry, 2018Co-Authors: I S Nizamov, Andrey A Yakovlev, D A Terenzhev, K A Ivshin, O N Kataeva, Marina P Shulaeva, Oscar K Pozdeev, E S BatyevaAbstract:Chiral S-tributylstannyl Dithiophosphates and dithiophosphonates were obtained by the reactions of optically active dithiophosphoric and dithiophosphonic acids containing (S)-(–)-menthyl and (R)-(+)-menthyl substituents with gaseous ammonia and tributyl chlorostannane. The reactions of chiral ammonium dithiophosphate containing (1R)-endo-(+)-fenchyl substituent with tributyl chlorostannane or tetrachlorostannane result in corresponding S-tributylstannyl dithiophosphate or tetrakis(dithiophosphato)stannane. Molecular structure of ammonium O,O-di-(–)-menthyldithiophosphate was studied by X-ray single crystal diffraction. Bactericidal activity of S-tributylstannyl Dithiophosphates was tested.
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Dithiophosphorylation of nerol and geraniol trimethylsilyl derivatives
Russian Journal of Organic Chemistry, 2017Co-Authors: I S Nizamov, D A Terenzhev, E S Batyeva, I. D. Nizamov, G. G. Shumatbaev, R. A. CherkasovAbstract:Reaction of tetraphosphorus decasulfide with О -( cis - and trans -3,7-dimethylocta-2,6-dien-1-yl)-trimethylsilanes affords О , О -bis( cis - and trans -3,7-dimethylocta-2,6-dien-1-yl) S -(trimethylsilyl)Dithiophosphates.
Pranesh B. Aswath - One of the best experts on this subject based on the ideXlab platform.
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chemical and mechanistic interpretation of thermal films formed by Dithiophosphates using xanes
Tribology International, 2017Co-Authors: Vinay Sharma, Pranesh B. AswathAbstract:Thermal films from zinc dialkyl dithiophosphate (ZDDP), an ashless shortchain dithiophosphate (DDP-1) and a longchain ashless dithiophosphate (DDP-2) were generated on steel substrates. XANES data was used to calculate phosphates chain lengths, P/S ratios and sulfate/sufide ratios at different time intervals and mechanistic models were proposed. The results indicate that presence of zinc metal cation in ZDDP allows thermal films to grow for extened period of time with the formation of ZnSO4, ZnS and polyphosphates of Zn. For DDP-1, the lower flash point results in quicker saturation of growth. DDP-2 exhibits a continous growth rate for extended period of time because of its thermal stability. DDP-1 and DDP-2 thermal films are composed of phosphates, sulfates and sulfides of iron.
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Properties of tribofilms formed with ashless dithiophosphate and zinc dialkyl dithiophosphate under extreme pressure conditions
Wear, 2010Co-Authors: Ramoun Mourhatch, Pranesh B. AswathAbstract:Tribological and nanoscale properties of tribofilms from ashless dialkyl Dithiophosphates (DDPs) were compared with zinc dialkyl Dithiophosphates (ZDDPs) in this study. The tribosurfaces generated from these chemistries were examined using scanning electron microscopy and energy dispersive spectroscopy. The wear debris harvested from the wear tests was examined in a transmission electron microscope in bright field mode with selected area diffraction to examine the crystallinity and nature of the debris particles. Thickness of the tribofilms was measured using the focused ion beam cross-section microscopy indicating that the tribofilms formed by ashless Dithiophosphates are significantly thicker than those formed by ZDDP. Nano-mechanical properties of the tribofilms including hardness and reduced modulus, scratch and nano-wear performance of the ashless dithiophosphate were compared to the secondary ZDDP. The overall results indicate that the wear performance of the ashless DDP are comparable or better than when ZDDP is used. The analytical techniques indicate that the tribofilms formed with ashless DDPs are thicker than those formed from ZDDP; however, the hardness and modulus of the tribofilm are lower in the case of ashless DDPs. XANES analysis indicate that in both tribofilms, phosphates are present as short chain phosphates. Ashless DDPs yield iron phosphates while ZDDP yielded a mix of iron and zinc phosphates. Both tribofilms have greater proportion of phosphates compared to sulfur species. The sulfur near the surface is mostly in the form of sulfates while the material in the interior is a mixture of sulfates and sulfides.
Rupali Rastogi - One of the best experts on this subject based on the ideXlab platform.
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synthesis spectral characterization and evaluation of antimicrobial activity of o o alkanediyl s n phthalimidomethyl Dithiophosphates and zinc bis o o alkanediyl Dithiophosphates
Phosphorus Sulfur and Silicon and The Related Elements, 2017Co-Authors: Rupali Rastogi, Srasti Gupta, Nazia Tarannum, Ranu Agarwal, Ray J ButcherAbstract:The synthesis of novel dithiophosphate derivatives has been achieved. Two O,O′-alkanediyl S-(N-phthalimidomethyl) Dithiophosphates and two Zinc bis(O,O′-alkanediyl) Dithiophosphates are synthesized...
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Synthesis, spectral characterization, and evaluation of antimicrobial activity of O,O′-alkanediyl S-(N-phthalimidomethyl) Dithiophosphates and zinc bis(O,O′-alkanediyl) Dithiophosphates
Phosphorus Sulfur and Silicon and The Related Elements, 2016Co-Authors: Rupali Rastogi, Srasti Gupta, Nazia Tarannum, Ranu Agarwal, Ray J ButcherAbstract:The synthesis of novel dithiophosphate derivatives has been achieved. Two O,O′-alkanediyl S-(N-phthalimidomethyl) Dithiophosphates and two Zinc bis(O,O′-alkanediyl) Dithiophosphates are synthesized...
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substituted diorganotin iv o o alkylene Dithiophosphates synthesis and spectral aspects
Phosphorus Sulfur and Silicon and The Related Elements, 2010Co-Authors: Sanjay K Srivastava, Rupali Rastogi, Shailja Tomar, Richa SaxenaAbstract:Six new substituted diphenyltin(IV) O,O′-alkylene Dithiophosphates, (C6H5)2Sn(X)S(S) POGO [G = —CH2C(CH3)2CH2—, X = Cl (1), SCN (3), ClO4 (5); G = —CH2C (C4H9)(C2H5)CH2—, X = Cl (2), SCN (4), ClO4 (6)], were synthesized by the reaction of the corresponding ammonium salts of the O,O’-alkylene Dithiophosphates with an appropriate organotin(IV) chloride. The compounds were characterized on the basis of elemental and spectral analyses (ESI mass spectrometry, IR, 1H, 13C, 31P, and 119Sn NMR). The presence of a four-coordinated Sn atom and monodentate O,O’-alkylene dithiophosphate moiety in compounds 1–4 as well as bidentate O,O’-alkylene dithiophosphate unit in compounds 5,6 is established.
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Substituted Diorganotin(IV) O,O’-Alkylene Dithiophosphates: Synthesis and Spectral Aspects
Phosphorus Sulfur and Silicon and The Related Elements, 2010Co-Authors: Sanjay K Srivastava, Rupali Rastogi, Shailja Tomar, Richa SaxenaAbstract:Six new substituted diphenyltin(IV) O,O′-alkylene Dithiophosphates, (C6H5)2Sn(X)S(S) POGO [G = —CH2C(CH3)2CH2—, X = Cl (1), SCN (3), ClO4 (5); G = —CH2C (C4H9)(C2H5)CH2—, X = Cl (2), SCN (4), ClO4 (6)], were synthesized by the reaction of the corresponding ammonium salts of the O,O’-alkylene Dithiophosphates with an appropriate organotin(IV) chloride. The compounds were characterized on the basis of elemental and spectral analyses (ESI mass spectrometry, IR, 1H, 13C, 31P, and 119Sn NMR). The presence of a four-coordinated Sn atom and monodentate O,O’-alkylene dithiophosphate moiety in compounds 1–4 as well as bidentate O,O’-alkylene dithiophosphate unit in compounds 5,6 is established.
Vinay Sharma - One of the best experts on this subject based on the ideXlab platform.
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chemical and mechanistic interpretation of thermal films formed by Dithiophosphates using xanes
Tribology International, 2017Co-Authors: Vinay Sharma, Pranesh B. AswathAbstract:Thermal films from zinc dialkyl dithiophosphate (ZDDP), an ashless shortchain dithiophosphate (DDP-1) and a longchain ashless dithiophosphate (DDP-2) were generated on steel substrates. XANES data was used to calculate phosphates chain lengths, P/S ratios and sulfate/sufide ratios at different time intervals and mechanistic models were proposed. The results indicate that presence of zinc metal cation in ZDDP allows thermal films to grow for extened period of time with the formation of ZnSO4, ZnS and polyphosphates of Zn. For DDP-1, the lower flash point results in quicker saturation of growth. DDP-2 exhibits a continous growth rate for extended period of time because of its thermal stability. DDP-1 and DDP-2 thermal films are composed of phosphates, sulfates and sulfides of iron.