نتایج جستجو برای: phosphonates
تعداد نتایج: 1275 فیلتر نتایج به سال:
Palladium(II)-catalyzed cycloisomerization of [(2-alkynylphenyl)hydroxymethyl]phosphonates 6 provides an efficient route to phosphonylated isochromenes 7 in THF at room temperature and the reaction proceeded in a regioselective manner leading to the 6-endo-dig products 7 in moderate to excellent yields.
The importance of phosphorus can be highlighted not only through its biological significance, but also in its many varied industrial, medicinal, and synthetic applications. Phosphonate moieties in particular have broad applications including their use as reagents in the Horner-Wadsworth-Emmons olefination reaction, a widely used synthetic strategy. As an alternative to the often harsh condition...
Phosphorothioate has proven to be a useful skeleton in organic synthesis as a valuable building block, in pharmaceuticals and pesticides due to its biological and physical properties. In particular, S-aryl phosphorothioate represents an important structural element in antiproliferative agents (A), pesticides (B), antibacterials (C), curing accelerators (D), antistatic agents (E), and anticholin...
Fluorinated and nonfluorinated phosphonates are employed as precatalysts in lithium phosphonate catalyzed cross benzoin couplings. Surprisingly, a decreased catalytic activity for the fluorinated precatalysts compared to the nonfluorinated systems is observed. Furthermore, the ring size of six, seven and nine membered ring catalysts appears not to be crucial for their catalytic activity.
Novel O-ethyl O-heteroaryl 2-chloroethyl phosphonates have been prepared by condensing 2chloroethyl phosphonyl dichloride by the sequential addition of ethanol and –OH and –SH carrying heteroaryls. Attempts of the above reaction with –NH carrying heteroaryl (benzimidazole) furnished a different product than the expected one by different reaction path.
Asymmetric addition under mild conditions of dialkyl phosphites on aldimines derived from cinnamaldehyde catalyzed by the inexpensive chiral organocatalyst (R)-3,3'-[4-fluorophenyl](2)-1,1'-binaphthol phosphate has been found effective to give new alpha-amino-phosphonates 9 in moderate yields (30-65%) and enantiomeric excess (8.4%-61.9%).
The ability of commercially available amino acid derivatives, especially Fmoc-Trp(Boc)-OH, to differentiate enantiomers of chiral phosphonates, phosphinates, phosphates, phosphine oxides, and phosphonamidates is demonstrated with (31)P, (13)C, and (1)H NMR spectroscopy. The chiral differentiation provided a rapid and convenient method for measuring the enantiomeric purity of these phosphorus co...
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