Phosphorus, Sulfur, and Silicon and the Related Elements最新文献

Our group introduced a green protocol for the Pd(OAc)₂- or NiCl₂-catalyzed P–C coupling reaction of aryl halides and various > P(O)H-compounds under MW conditions without directly added P-ligands. The reactivity of a few aryl derivatives in the Pd(OAc)₂-catalyzed Hirao reaction was also studied. An induction period was observed in the reaction of bromobenzene and diphenylphosphine oxide. Finally, the less known copper(I)-promoted P–C coupling reactions were investigated experimentally. The mechanism was explored by quantum chemical calculations.

The phosphorus–oxygen bond formation reactions often observed for the sterically crowded triarylphosphines and their radical cations were studied by DFT calculation. The oxidations of the trimethyl-, triphenyl-, and trimesityl-phosphines to the corresponding phosphine oxides with peroxides are shown to proceed through the S_N2 like transition states and the overall influence of the steric hindrance on the activation energy is limited. The reaction of the radical cation of tris(2,4,6-triisopropylphenyl)phosphine with oxygen to give the heterocyclic phosphonium cation is modeled by employing (2,6-diisopropylphenyl)diphenylphosphine and the comparison of the intermediates suggests highly exergonic nature of the reaction.

Chiral P*,S-diamidophosphites with a 1,3,2-diazaphospholidine core and exocyclic 1,2-hydroxyl-thioether fragments were prepared. These asymmetric inducers provided up to 86% ee in the Pd-catalyzed allylic substitution of (E)-1,3-diphenylallyl acetate with dimethyl malonate and pyrrolidine, and up to 76% in the Pd-mediated allylic alkylation of cinnamyl acetate with ethyl 2-oxocyclohexane-1-carboxylate.

1. Download : Download high-res image (99KB)
2. Download : Download full-size image

Herein we report the mild synthesis of 15 phosphonocinnamic esters by means of a solvent-free mechanically activated Horner-Wadsworth-Emmons (HWE) olefination, in regular to excellent yields (13–99%), from tetraethyl methylenediphosphonate, an aromatic or aliphatic aldehyde and potassium tert-butoxide, using 5 min of mortar and pestle grinding. Potassium tert-butoxide acts as a base and liquid-assisting grinding agent. All isolated products were fully characterized as (E)-isomers through NMR spectroscopy. Furthermore, among the synthesized compounds diethyl (E)-2-(4-methoxyphenyl)vinylphosphonate 1 was discovered as an interesting cytotoxic agent inhibiting growth of two breast cancer cell lines (MDA-MB-453, IC₅₀ = 79 µg/mL and MCF-7 IC₅₀ = 64 µg/mL). To the best of our knowledge, this is the first report of mechanically activated HWE reaction for the synthesis of α, β-unsaturated phosphonates and the first time some of them have been assessed as cytotoxic agents on breast cancer cell lines. In conclusion, the fast and operationally simple synthesis of (E)-phosphonocinnamic esters afforded new promising cytotoxic agents in regular to excellent yields in very short reaction times.

The adduct of acetylenedicarboxylic acid and the water-soluble 1,3,5-triaza-7-phosphaadamantane (PTA, 1) in 1:2 molar ratio, was synthesized both in aqueous solution and under anhydrous conditions in a planetary ball mill (pbm). The resulting double phosphabetaine (2) was characterized by ¹H-, ¹³C-, and ³¹P-NMR spectroscopy, ESI-mass spectroscopy, and elemental analysis, furthermore, its solid-state structure was determined by single crystal X-ray diffraction. SXRD also revealed that in aqueous solution 2 reacted with AgSO₃CF₃ to yield a 2 D polymer.

This review deals with the chemistry of thiocarbamoyl derivatives, their biological importance and their medicinal and industrial applications. Thiocarbamoyl derivatives can be easily prepared from a large variety of isothiocyanates and active methylene compounds or amines under varying reaction conditions.

The vapor-phase phosphorylation of cellulose by means of phosphorus trichloride (PCl₃) and phosphorus oxychloride (POCl₃) is presented. It was found that cellulose-O-dichlorophosphines (Cell-O⁶-PCl₂) formed by the reaction of cellulose with PCl₃ and cellulose-O-dichloro-oxyphosphines (Cell-O⁶-P(O)Cl₂) formed by the reaction with P(O)Cl₃ have been hydrolyzed to cellulose-O-hydrogenphosphates (P(III/V)) (Cell-O⁶-P(O)(H)-OH and (Cell-O⁶-P(O)(OH)₂), respectively. Selected chemico-physical properties (SEM-EDS, ³¹P NMR, potentiometric titration) of both types of cellulose phosphates (Cell-O⁶-O-P(O)(H)-OH and Cell-O⁶-O-P(O)(OH)₂) were compared.

The aminolysis reactions of hexachlorocyclotriphosphazene, [N₃P₃Cl₆] (1a) and dispiro-2,2′-biphenoxydichlorocyclotriphosphazene [N₃P₃Cl₂[(2,2′-biphenoxy)₂] (1b) with 6-aminoquinoline (2) were carried out to examine the spectroscopic properties of cyclotriphosphazene derivatives combined with 6-aminoquinoline. For the first time, two new aminoquinoline-substituted cyclotriphosphazene derivatives (3a, b) were obtained in this study. Both compounds (3a, b) have been characterized by elemental analysis, FT-IR analysis, MALDI-TOF mass spectrometry, ¹³C, ¹H, and ³¹P NMR spectroscopies. The molecular structure of 3b has been confirmed by single crystal X-Ray crystallography. The crystal structure of 3b was investigated in detail to determine the remarkable intermolecular interactions. Furthermore, the photophysical properties of compounds 3a and 3b were determined by using UV/vis and fluorescence spectroscopies.

Four new water-soluble bidentate ligands, namely, (cyclopentadienyl)ethyl-1,3,5-triaza-7-phosphadamantane (1), 1,2-bis-(1,3,5-triaza-7-phosphaadamantan-6-yl) ethane (2), 1,3-bis-(1,3,5-triaza-7-phosphaaadamantan-6-yl) propane (3) and 1,4-bis-(1,3,5-triaza-7-phosphaadamantan-6-yl) butane (4) have been synthesized and characterized by multi-nuclear NMR (¹H, ¹³C and ³¹P), elemental analysis and mass spectrometry. Compound 1 was synthesized by using two different synthetic routes in excellent yields and is also the first example of water-soluble chelating cyclopentadienyl ligand containing 1,3,5-triaza-7-phosphaadamantane.