Reactions of dithioxo-1,3,2λ5,4λ5-dithiadiphosphetanes with triorganolead derivatives

The reactions of Lawesson's reagent 1a and its 4-ethoxy homologue 1b with triethyl- and triphenyl(alkoxy)plumbanes 2a,b and -(alkylthio)plumbanes 4a,b were studied. On the basis of these reactions, novel, advantageous methods of synthesizing S-triethyl and triphenylplumbyl derivatives of aryldithio- and trithiophosphonic acids 3a–d and 5a,b were developed. © 1997 John Wiley & Sons, Inc.     

λ3σ3P and λ5σ5P derivatives of (E)-1,2-difluoro-2-(pentafluoro-λ6-sulfanyl)ethylene and (Z)-1,2,3,3,3-pentafluoropropylene

For the first time, the (E)-1,2-difluoro-2-(pentafluoro-λ⁶-sulfanyl)ethenyl group has been bonded to λ³σ³ phosphorus using a Grignard reagent. Similar phosphorus derivatives containing the (Z)-1,2,3,3,3-pentafluoropropenyl moiety were also synthesized for comparison. In three cases, hexafluoroacetone was added to form 4,4,5,5-tetrakis(trifluoromethyl) 1,3,2λ⁵σ⁵-dioxaphospholanes. © 1997 John Wiley & Sons, Inc. Heteroatom Chem 8: 467–471, 1997     

Reactions of dithioxo-1,3,2λ5,4λ5-dithiadiphosphetanes with trialkylsilyl and stannyl derivatives

The reactions of homologues of Davy's reagent 1 and Lawesson's reagent 9 with trimethylalkylthiosilanes 2 , trimethylsilyl enol ether 4 , trimethyl(diethylamino)silane 7 , trialkylalkoxystannanes 14 , and trialkylalkylthiostannane 15 were studied. On the basis of these studies, novel advantageous methods of synthesizing S-trialkylsilyl and stannyl esters of tetrathio-, trithio-, and amidotrithiophosphoric acids 3 , 5 , 6 , and 4-methoxyphenyldithio- and trithiophosphonic acids 10–13 were developed     

Synthesis and γ-radiolysis of 2′-deoxy-5-fluorouridine and 5-fluorouridine derivatives

Seventeen compounds having a variety of substituents at the 3- and 5′-positions of 2′-deoxy-5-fluorouridine (5-FUdR) and 5-fluorouridine (5-FUR) were synthesized, and their γ-radiolysis in aqueous solutions were studied. The compounds having thioureido (RNHCSNH, R  H, PhCH₂, acyl) and thiocarbonylamino (XCSNH, X  PhCH₂S, PhO) groups at the 3-position of 5-FUdR were efficiently cleaved to give 5-FUdR with high G values upon γ-irradiation of their aqueous solutions. The active species for these cleavage reactions were hydrated electron (e⁻ _aq), H^• and HO^•. However, the compounds having a dimethylsulfoxyimino group at 3-position of 5-FUdR and 5-FUR afforded 5-FUdR and 5-FUR only under the radiolysis conditions where e⁻ _aq becomes a principal active species. The compound having a 2-benzoylthiazoylthiocarbonylamino group at the 3-position of 5-FUdR showed the highest reactivity toward HO^.. The mechanisms of these γ-radiolysis reactions are discussed. The examination of anticellular activities of γ-irradiated compounds having a thiocarbonylamino group at the 3-position of 5-FUdR toward murine Sarcoma 180 cells revealed that these compounds may be utilized as a candidate for a radiation-induced drug (RID).     

(σ3,λ5)‐phosphoranes versus (σ3,λ3)‐thiaphosphiranes: Quantum chemical investigation of products of phosphaalkene sulfurization

By sulfurization of phosphaalkenes ( a ) either (σ³,λ⁵)‐phosphoranes ( b ) or (σ³,λ³)‐thiaphosphiranes ( c ) are formed. In this study, Density Functional Theory (DFT) and coupled cluster (CCSD(T)) calculations have been carried out for model and experimental structures of (σ³,λ⁵)‐phosphoranes and (σ³,λ³)‐thiaphosphiranes to elucidate the factors influencing relative stabilities of b and c . According to the results of quantum chemical calculations, sterically bulky substituents make the phosphorane form more favored. Conversely, electronic effects of the most substituents provide higher stability for thiaphosphirane isomers. The only exception has been found in the cases where the substituent at the phosphorus atom possesses π‐donor and σ‐acceptor properties (e.g., in the case of amino group) and the substituents at carbon atom exhibit σ‐donor/π‐acceptor effects (e.g., silyl groups). The stability of the cyclic form c decreases further, if the substituents at the carbon atom are amino groups. In this case, a quite unusual structure has been theoretically predicted, which is considerably different from those of the hitherto known phosphoranes. It indicates a pyramidal configuration at the phosphorus atom and can be conventionally presented as a donor–acceptor adduct of diaminocarbene with thioxophosphine. © 2012 Wiley Periodicals, Inc.     

1λ5,3λ5-Diphospholium ions

One example each is given for the reaction of bromoacetylenes and ethynyl-phenyliodonium tosylates with bis(diphenyl phosphino)methane. The yellow crystalline 1:1-addition products are diphospholium salts. They readily and selectively hydrolyze to give 2-phosphinoylethenyl phosphonium salts.     

1,2λ5,5λ5-azadiphospholium structures

The reactions of bromophenylacetylene with the diphenylphosphino amines (Ph₂P)₂NH and (Ph₂P)₃N result in the 1,1,3,3,4-pentaphenyl-1,2,5-azadiphospholium bromide ( 5 ) and its 4-diphenylphosphino derivative ( 7 ). Their X-ray structure analyses show planar rings for the cations. The small endocyclic angle at the nitrogen ring member is associated with PN bonds that are longer than in the acyclic cation (Ph₃P)₂N⁺. The data fit to a negative linear relationship of PN bond lengths and PNP bond angles. © 1997 John Wiley & Sons, Inc.