LD3- and λ5-1,3-Diphosphacyclobutadienes by Dimerisation of λ3- and λ5-Phospha-alkynes

Abstract

λ³-Phosphaalkynes 1 dimerize in the presence of cyclopentadienylcobaltbis (ethylene) (2) to yield λ³-1,3-diphosphacyclobutadienes, which are stabilized by complex formation (3). An excess of 2, finally, is responsible for the formation of the complex 4.     

Polarity of [sgrave]3,λ5-Phosphoranes

Abstract

Tricoordinated pentavalent phosphorus compounds- [sgrave]³,λ⁵-phosphoranes-present a new field in unusually (low) coordinated phosphorus chemistry. Our current interest in these compounds is stimulated by the possibility of actual determination of unknown phosphorus bond polarities, using electrical methods in subsequent investigations of the spatial and electronic structure of [sgrave]³,λ⁵ -phosphoranes. We have studied the series of bis(imino)phosphoranes by the method of dipole moments R²N=P (R¹)=NR³ (I-VI) R¹ R² R³,^μexp.^{(D): (I) N}(^SiMe ₃)₂, ^SiMe ₃, SiMe₃, 2.16; (11) t-Bu, t-Bu, 2.36; (111) N(SiMe₃)₂, SiMe₃, t-Bu, 2.26; (IV) 2,4,6-Me₃C₆H₂, t-Bu, 2,4,6-t-Bu₃C₆H₂, 2.44; (V) t-Bu(Me₃Si)N, t-Bu, t-Bu, 2.74; (VI) c-2,2,6,6-Me4C5H6N, SiMe₃, SiMe₃, 2.82 and defined P=N bond polarity (3.14D). Dipole monents (I-VI) are described by the given values, the group moments R-P and R-N were previously found from dicoordinated phosphorus compounds. The tendency of increasing ^μexp, with the growth of n,Π-donor abilities of ^μexP,₁ substituent R in row (I-III)-(V)-(VI) is possibly caused by the increase of the conjugative effect contribution in stabilization of the 4-electron 3-centre Π-system N=P=N.     

Synthesis and Reactivity of the First Stable λ5-Phosphaacetylene

Abstract

The synthesis and reactivity of he P-bis(diisopropylamino) trimethylsilylphosphaacetylene (bp 75–80°C/10^?2) is reported. Addition of trimethylsilyltriflate to this compound leads to a stable methylenephosphonium salt which has been characterized by an X-ray diffraction study.     

Synthesis,Electronic Properties and OLED Devices of Chromophores Based on λ5-Phosphinines

A new series of 2,4,6-triaryl-λ⁵-phosphinines have been synthesized that contain different substituents both on the carbon backbone and the phosphorus atom of the six-membered heterocycle. Their optical and redox properties were studied in detail, supported by in-depth theoretical calculations. The modularity of the synthetic strategy allowed the establishment of structure–property relationships for this class of compounds and an OLED based on a blue phosphinine emitter could be developed for the first time.     

P-Functionalized λ3-Iminophosphines and Diphosphenes

Abstract

The synthesis of P-functionalized iminophosphines and diphosphenes is discussed. The reactivity and the coordination chemistry of selected compounds have been explored.     

Preparation and properties of diuridine 3'''',5''''-boranophosphate

Diuridine 3', 5'-boianophosphate has been synthesized. Its diastereomers were separated and their configurations were tentatively assigned based on the selective snake venom phosphodiesterase (SVPDE) hydrolysis. It is found that, compared to the unmodified parent compound diuridine phosphate, the nucleophilicity and the stability of the modified compounds to SVPDE are significantly enhanced.     

Molecular and Crystal Structure of 2, 3, 5, 6-dipropylene-r-pyrone

11NTRODUCT1ONWeattemptedtosynthesizeanextractant(1)bythereactionofadipylchloridewithcyclopentanonepiperidineenamineaccordingtoHunig'sprocedure"',however,wemainlyobtainedthetitlecompound,whichmaybepossiblyapotentialmedicinet2'3i.Itsmolecularstructurewasfinallyconfirmedbythesingle-crystalstructuredeterminationafterconventionalUV,IR,lHNMR,MSandelementana-lyticalworks.2EXPER1MENTALSECT1ON2.1SynthesisToastirredsolutioncontaining8Omlofchloroform,2.8mloftri-ethylamineand1.51g(O-Olmol)…     

10-Oxo-10H-5λ,10λ-thianthren-5-ylideneamine as a probe for stereochemistry in the formation and amination of fluoro-λ-sulfanenitriles

The fluorination of 10-oxo-10H-5λ⁴,10λ⁴-thianthren-5-ylideneamine (2) with Selectfluor™ affords 5-fluoro-10-oxo-5,10-dihydro-5λ⁶,10λ⁴-thianthren-5-nitrile (4). The amination of 4 with morpholine gives 5-morpholino-10-oxo-5,10-dihydro-5λ⁶,10λ⁴-thianthren-5-nitrile (5). The stereochemical course of both reactions has been studied, while the configurations of their products, cis-isomer 4 and trans-5-morpholino-10-oxo-5,10-dihydro-5λ⁶,10λ⁴-thianthren-5-nitrile (trans-5) are elucidated by the use of X-ray crystallographic analyses.     

Highly Diastereoselective Synthesis of Anomeric β-O-Glycopyranosyl σ3λ3-and σ4λ5-Phosphorus Compounds

Abstract

A new method for the highly stereoselective synthesis of β-O-σ³λ³ and σ⁴λ⁴ phosphorus-substituted 2,3,4,6-tetrabcnzylglucose is presented. The β-diastereoselective synthesis of the carbohydrates containing σ³λ³ and σ⁴λ⁵ phosphorus groups could be accomplished via two main synthetic routes. The first involves the addition of the σ³λ³-phosphorus derivative 3 to the 2,3,4,6-tetrabenylglucose derivative 1 (αβ = 1:l) in toluene and triethylamine as a catalyst to provide the σ³λ³ phosphorus derivative 4 with practically 100% β-diastereoselectivity.     

A Simple Synthesis of 3H-λ5-Phosphole Derivatives from Alkyldiphenylphosphine Imines and Dimethyl Acetylenedicarboxylate

Abstract

Whereas several procedures have been developed for synthesizing λ³-phospholes and their oxides and sulphides¹, access to 2H-λ⁵-Phospholes is limited to the reaction of phosphines² with Dimethyl Acetylen-dicarboxilate (DMAD) and only unstable 3H-λ⁵-Phospholes were detected² when diphenylvinylphosphine were used.     

Synthesis of 6-chloronicotinates of steroidal 3β,5α,6β-triols and 3β,5-dihydroxy-6-ketones

New esters of 3β,5α,6β-trihydroxysteroids and 3β,5-dihydroxy-6-ketosteroids containing 6-chloropyridine groups characteristic of the alkaloid epibatidine were synthesized by acylation with 6-chloronicotinoylchloride. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 175-179, March-April, 2009.     

Oxidation of 1,3-Dioxacycloalkanes with Complexes of Potassium Chlorochromate and Chlorodiperoxochromate with 15-Crown-5, Catalyzed with 2,2,5,5-Tetramethyl- 4-phenyl-3-oxo-3λ5-imidazolin-1-yloxyl

2,2,5,5-Tetramethyl-4-phenyl-3-oxo-3⁵-imidazolin-1-yloxyl catalyzes oxidation of 2-isopropyl-1,3-dioxolane, 2-phenyl-1,3-dioxolane, 2-phenyl-4-chloromethyl-1,3-dioxolane, and 2-phenyl-1,3-dioxane with 15-crown-5 complexes of potassium chlorodiperoxochromate (KCrO₅Cl·2C₁₀H₂₀O₅) and potassium chlorochromate (KCrO₃Cl·2C₁₀H₂₀O₅). 2-Isopropyl-1,3-dioxolane is oxidized to the corresponding monoester in quantitative yield, and the 2-phenyl derivatives yield benzaldehyde. The spiro ketal, 2,2-pentamethylene-4-methyl-1,3-dioxane, is decomposed to cyclohexanone.     

Preparation and X-Ray Structure of 3,4,8-Tris(T-Butyl)- 1,6-Bis(4-Trifluormethylphenyl)-2,5,7,9-Tetraza-3λ3, 4λ5 8λ3-Triphospha [4.3.0]Bicyclonona-1,4,6-Trien (4). Study of the Thermal Stability of 4, and two Other Ci- Clocarbophosphazenes

Abstract

In this work, we expose the synthesis of the new bicyclocarbophosphazene 4, its x-ray crystall structure and the experimental data obtained. The results of the study of thermal stability of 4 and two related compounds are also presented.     

CRYSTAL STRUCTURE OF THE NOVEL COMPOUND (1α, 3bT, 5α)-1,3-DIPHENYL-5-HYDRIDO-5-ISOPROPOXY-1λ6, 3λ6,2,4,6,5λ5-DITHIATRIAZAPHOSPHORINE-1,3-DIOXIDE. A COMPARISON WITH RELATED STRUCTURES

Abstract

The title compound (1α, 3β, 5α)-(NSOPh)₂NP(H)O-i-Pr crystallizes in the spacegroup P2₁/n with cell dimensions: a = 12. 150(2), b = 8.911(1), c = 17.614(3) Å, β = 107.52(1)^o; Z = 4. The structure was solved by direct methods and refined by least-squares techniques to an R value of 0.048 for 2420 independent reflections (collected at room temperature) with I > 2.5 σ(I). The unit cell contains dimeric units which are formed by unprecedented P[sbnd]H…O[dbnd]S bridges. The conformation of the inorganic ring skeleton can be described as a boat; phosphorus and sulfur atoms show a distorted tetrahedral geometry. The S[sbnd]N bond lengths differ slightly, ranging from 1.547(3) to 1.588(2) Å. The exocyclic bond lengths are P[sbnd]H = 1.34(2), P[sbnd]O = 1.553(2), S[sbnd]O = 1.439(2) (mean value), and S[sbnd]C = 1.767(4) (mean value) Å. From a comparison with analogous structures the degree of asymmetry (ΔI = {[P[sbnd]N]-[S[sbnd]N]}Å) in the SNP unit is related to the difference in electronegativity between the sulfur and phosphorus centres.     

Enzymatic Synthesis and Characterization of Novel Polycarbonates Derived from 5-Allyloxy-1, 3-dioxan-2-one and 5, 5-Dimethyl-1, 3-dioxan-2-one

Aliphatic polycarbonates and their copolymers have been used in drug controlled release system and other biomedical applications due to their good biocompatibility, favorable mechanical properties and some elasticity1, such as poly(1, 3-dioxan-2-one)2 and…     

Synthesis of new α-chloropyridine derivatives of steroidal 3β,5α,6β-triols and 3β,5-dihydroxy-6-ketones

New steroid derivatives containing 6-chloropyridine groups characteristic of the alkaloid epibatidine and neonicotinoid insecticides were synthesized by reacting 3β,5α,6β-trihydroxysteroids or 3β,5-dihydroxy-6ketosteroids with 2-chloro-5-chloromethylpyridine. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 180-182, March-April, 2009.     

Molecular and crystal structure of 2-phenoxy-2λ5-2,2′(3H,3′H)-spirobi[1,3,2-benzoxazaphosphole]

The crystal and molecular structure of 2-phenoxy-2⁵-2,2(3H,3H)-spirobi[1,3,2-benzoxazaphosphole] has been determined using X-ray diffraction structure analysis. The P atom in the molecule in question has a distorted trigonal bipyramidal coordination, with the bond lengths P-O_ax=1.701(1) and 1.700(1) Å, P-O_eq (Ph)=1.625 Å, P-N_eq=1.654(2) and 1.645(1) Å, and bond angles (O-P-O)_ax=175.69(7)° and (N-P-N)_eq = 132.38(7)°.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 876–879, May, 1993.     

Nucleophilic Addition-Oxidation Reactions of σ3,λ3 Dialkyl(Silylamino)Phosphines with Mono and Disubstituted Acetylenes

Abstract:

Dialkyl(silylamino)phosphines R₂PNT₂ undergo a nucleophilic addition-oxidation reaction with either mono- or di-substituted acetylenes which is followed by a silyl migration to form phosphoranimines with unsaturated substituents. The reaction route depends on the substituent on the acetylenic carbon atom. Reactions of the acetylenes with dialkyl(silylamino)phosphines show high chemo and regio selectivity for addition to the triple bond in the formation of the alkene phosphoranimines. The reaction of (silylamino)-phosphines with α,β-acetylenic carbonyl compounds is more complicated; the reaction route depends critically on the substituents at both the carbonyl and the β-acetylenic carbon atoms.     

Synthesis and Fungicidal Activities of 2-Alkylthio-5- （3, 4, 5-tribenzyloxyphenyl）-1, 3, 4-oxadiazoles

Abstract： Ten novel 2-alkylthio-5-（3, 4, 5-tribenzyloxyphenyl）-1, 3, 4-oxadiazole derivatives （5a-j） were synthesized from methyl 3, 4, 5-trihydroxybenzoate by ethedfication, hydrazidation, cyclization and thioetherification reactions. The structures of 5a-j were confirmed by 1HNMR, MS spectra and elemental analysis. The results indicated that most of the compounds 5 exhibited good fungicidal activities. The activity of 5h is higher than 90% against Fusarium oxysporum and Botrytis cinereapers in 50 mg/L.