One-pot carbanionic synthesis of P1,P2-diglycosyl, P1,P1,P2-triglycosyl, and P1,P1,P2,P2-tetraribosyl methylenediphosphonates

Novel lithiated carbanions derived from ethyl glycosyl- and diglycosyl methylphosphonates were used in a direct and convenient synthesis of P1,P2-diglycosyl, P1,P1,P2-triglycosyl, and P1,P1,P2,P2-tetraribosyl methylenediphosphonates involving a one-pot methylidenediphosphonylation of sugars.     

Synthesis and thermal kinetic study of phosphoric acid,P, P′-1, 4-phenylene P,P, P′, P′-tetraphenyl ester

Journal of Thermal Analysis and Calorimetry - A phosphorous flame retardant of phosphoric acid, P, P′-1, 4-phenylene P, P, P′, P′-tetraphenyl ester (PAPTE) was synthesized by...     

Struktur und Farbigkeit von P,P′-Tetra-t-butyl-und P,P′-Tetraphenyl-oxalsäurediphosphid und Derivaten

The unexpected violet colour of P,P-tetraphenyl-oxalic acid diphosphide (3) stimulated the synthesis of the following derivatives: P,P-tetra-t-butyl-oxalic acid diphosphide (2), N,P-tetraphenyl-oxalic acid amide phosphide (4) and P, -triphenyl-glyoxylic acid phosphide (5). The compounds could be prepared by the reaction of the corresponding acyl chlorides with diorganyl-(trimethylsilyl) phosphine; (organyl=t-butyl and phenyl). The electronic transitions of green-blue2 and red5 in the 450–700 nm region are discussed, also theirv C=O in the ir spectrum. These results are interpreted in connection with the molecule structures of2 and3 which have been determined by X-ray crystal structure analysis. In2 the framework P–C(O)–C(O)–P is only slightly distorted from a coplanartrans-position, in3 somewhat more. The bonds at P have the expected pyramidal arrangement. The direction of the lone pairs at the P-atoms, derived from this bond arrangement, is discussed with respect to the electronic transitions in acyl phosphides.

     

Concise Synthesis of P-Glycosyl Alkenylphosphonates and P,C-di and P,P,C tri-Glycosyl Phosphonates

A direct access to P-glycosyl-, P, P-di-glycosyl alkenylphosphonates and P, C-glycosyl phosphonates is described. The method involves the Horner reaction of an anion derived from P-monoglycosyl and P ¹, P′-diglycosyl methylenediphosphonates either on the exocyclic aldehyde group of carbohydrates or on the masked aldehydic form of the furanose hemiacetals. In this last case, the carbonyl olefination, followed by an intramolecular cyclization, leads to P,C-di and P,P,C-triglycosyl phosphonates.     

Ruthenium complexes with ferrocene-based P,C,P pincer ligand

First ruthenium complexes with a ferrocene-based pincer ligand were synthesized. The cyclometallation of 1,3-bis[(di-tert-butylphosphino)methyl]ferrocene with RuCl₂(DMSO)₄ in 2-methoxyethanol afforded the RuCl(CO)[{2,5-(Bu^t ₂PCH₂)₂C₅H₂}Fe(C₅H₅)](RuCl(CO) ) complex (5). Complex 5 reversibly binds CO to form the RuCl(CO)₂ complex (6). The analogous reaction in the presence of NaBAr′₄ (Ar′ = 3,5-(CF₃)₂C₆H₃) produced the cationic complex {Ru(CO)₂ }BAr′₄ (7). The structures of complexes 5 and 7 were established by single-crystal X-ray diffraction. The X-ray diffraction study revealed an agostic interaction between one of the C-H bonds of the axial (exo-oriented with respect to the ferrocene iron atom) tert-butyl group and the Ru atom in complexes 5 and 7. Dedicated to Academician G. A. Abakumov on the occasion of his 70th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1695–1701, September, 2007.     

Chemistry of Several Sterically Bulky Molecules with P=P,P=C,and C≡P Bond

Several sterically protected, low-coordinate organophosphorus compounds with P=P, P=C, and C≡P bond are described in this study. Molecules such as diphosphenes, phosphaalkenes, 1-phosphaallenes, 1,3-diphosphaallenes, 3,4-diphosphinidenecyclobutenes, and phosphaalkynes are stabilized with an extremely bulky 2,4,6-tri-t-butylphenyl (Mes*) group. The synthesis, structures, physical, and chemical properties of these molecules are discussed, together with some successful applications in catalytic organic reactions.     

Phenylpropanoid glycosides of Pedicularis condensata,P. wilhelmsiana,and P. sibthorpii

A. L. Mndzhoyan Institute of Fine Organic Chemistry, Armenian Academy of Sciences, Erevan. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 723–724, September–October, 1991.     

Convenient and improved protocols for the hydrogenation of esters using Ru catalysts derived from (P,P), (P,N,N) and (P,N,O) ligands

An improved protocol where a pre-cursor, [Ru(Cl)(2)(NBD)(Py)(2)], is treated with ligands to form [RuCl(2)(bidentate ligand)(diamine)] pre-catalysts for ester hydrogenation is reported. This family of catalysts, as well as a range of ruthenium complexes of tridentate P^N^X (X = NR(2), OH) ligands have been investigated in the hydrogenation of aromatic esters. A range of aromatic esters can be hydrogenated in high yields at temperatures between 30 °C and 100 °C.     

New P,N-Cyclic Ligands

Abstract

The anions of P,N-cyclic metaphosphimic acids (MPm^n-, n = =3, 4…) interact with cations as conformationally labile multidentate ligands. They belong to the cyclophosphazane class and can be obtained from chloroderivatives (NPCl₂)_n associated with a related class of P,N-compounds (cyclophosphazenes. Besides halogens, a great variety of organic radicals can act as substituents in the cyclophospnazenes. An additional introduction of donating atoms or groups in these radicals results in new multidentate ligands. Like the MPm^n- they demonstrate a cation binding ability. Thus P,N-cyclic ligands can contain endocyclic functional groups POO- which are inherent to common MPm^n- or various exo-cyclic groups, e.g. -COO^?, -PR₂O^?, -PROO^?, -NR₂etc., linked to the cycle via side chains. Furthermore, miscellaneous phosphazane-phosphazene structures as well as those with an additional heteroatom can be designed. We have obtained the first examples of P,N-cyclic chelantes of some structural types. These are bicycles based on MPm^n- cross-linked by organic bridges. Such ligands can take a sandwich configuration. Neutral and acido-ligands of cyclo-pendante type involving groups -COO^?, -PPh₂O and >O as well as a ligand with endocyclic sulfur have been obtained too. Selective or universal chelantes, extragents, coloured ligands and other reagents can be synthesized depending on a ligand structure design, the nature of organic fragments linked to the cycle and the type of functional groups.     

Ladder-type P,S-bridged trans-stilbenes

Phosphole-containing π-systems have emerged as building blocks with enormous potential as electronic materials because of the tunability of the phosphorus center. Among these, asymmetric P-bridged trans-stilbenes are still rare, and here an elegant and efficient synthesis toward such fluorescent molecular frameworks is described. Fine-tuning of the photophysical properties is attempted by enforcing the planarization of the phosphorus tripod and thus increasing the interaction between the phosphorus lone pair and the π-system. The electronic structure of the π-conjugated frameworks is analyzed with NMR, UV-vis and fluorescence spectroscopy, and time-dependent density functional theory (TD-DFT) calculations.     

ChemInform Abstract: Theoretical Study of the Stability of Molecular P2, P4, and P8.

Ab initio calculations for P2, P4 and P8 on the SCF level and with inclusion of valence correlation effects, except for P8.