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New improved PPA Akabori Synthese | Hydrochloric …

To enhance or extend its performance, it is often modified with a polymer, including polyphosphoric acid (PPA).

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Polyphosphoric Acids As A Reagent In Organic Chemistry

Handling, Storage, and Precautions: normally used as the solvent so that a 10–50 fold excess is routinely employed. Due to high viscosity, PPA is difficult to pour and stir at rt, but is much easier to work with at temperatures above 60 °C. Addition of cosolvents, such as xylene, has facilitated the difficult workup usually associated with PPA. Eaton's reagent (see Phosphorus(V) Oxide–Methanesulfonic Acid) has been found to perform similar chemistry at lower temperatures without the viscosity problems. When diluting PPA or working up a reaction, ice is normally used to moderate the exothermic reaction that occurs with water. PPA has the ability to burn mucous membranes immediately and unprotected skin with time. Other than the corrosive nature of this reagent it has low inherent toxicity. Use in a fume hood.

Dodd, J. H. 2001. Polyphosphoric Acid. e-EROS Encyclopedia of Reagents for Organic Synthesis. .

In conclusion, the effect of the PPA concentration on regioselectivity for the synthesis of indanones was examined. It was found that the theoretical P2O5 content in PPA has a profound effect on the selectivity of this reaction and that this can be exploited for the regioselective synthesis of indanones. The explanation for the change in selectivity is attributed to the fact that at high PPA concentration mixed phosphoric anhydrides are formed with the substrate, whereas at low PPA concentration this does not occur. This is, as far as we know, the first synthetic methodology in which the degree of hydrolysis of PPA was used as a way to control the regioselectivity of a PPA-mediated reaction. The developed procedure allows facile and selective access to electron-rich indanones, as was demonstrated by the synthesis of a natural sesquiterpene .

Phenylpropanolamine and Cathinone from …

Phenylpropanolamines from Propenylbenzenes - Erowid

We envisioned that the P2O5 content in PPA can be a key control parameter in the selective alkylation versus acylation in the PPA-mediated synthesis of indanones.[] A change in the regioisomer ratio, depending on the polyphosphoric acid concentration, has been observed for a perimidine heterocycle.[]

In this letter, the effect of the P2O5 content in PPA on the regioselectivity for the synthesis of indanones is examined. It was found that the regioselectivity can be effectively switched, depending on the degree of hydrolysis of PPA (Scheme []). A mechanistic rational is given for the observed change in regioselectivity, together with supporting 31P NMR spectroscopic studies. Additionally, the natural product sesquiterpene and its unnatural regioisomer were synthesized selectively by using the developed protocol to demonstrate its synthetic value.

Maryland PPA: "Fine Art Photo-Synthesis" by Bob Coates

High-Level Synthesis Uncovers PPA Tradeoffs of …

The degree of hydrolysis of polyphosphoric acid (PPA) has a crucial effect on the regioselectivity of the PPA-mediated synthesis of indanones. It was found that the regioselectivity can be switched by employing PPA with either a high or low content of P2O5. This methodology was used for the regioselective synthesis of a range of electron-rich indanones, including a natural sesquiterpene.

Introduction In biology the term lipid can refer to almost any molecule hydrophobic enough such that it would partition into an organic solvent from an aqueous solution. Major lipids in plants include the glycerolipids and other fatty acid derivatives, isoprenoids and some phenylpropanoids. In the narrow sense lipids only include glycerolipids. In the next 3 lectures we will discuss the metabolism of glycerolipids and some other important fatty acid derivatives.

Author: Subject: questions regarding PPA synthesis
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  • Polyphosphoric Acid (115%) Uses

    06/01/2015 · High-Level Synthesis Uncovers PPA Tradeoffs of Various Hardware Accelerators

  • catalyst and the synthesis of PPA have been included.

    Polyphosphoric Acid Uses

  • Design and Synthesis of Phosphonoacetic Acid (PPA) …

    (PPA) has a crucial effect on the regioselectivity of the PPA-mediated synthesis of indanones.

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Efficient PPA-SiO 2 -catalyzed Synthesis of β ..

The degree of hydrolysis of polyphosphoric acid (PPA) has a crucial effect on the regioselectivity of the PPA-mediated synthesis of indanones. It was found that the regioselectivity can be switched by employing PPA with either a high or low content of P2O5. This methodology was used for the regioselective synthesis of a range of electron-rich indanones, including a natural sesquiterpene.

Phenylpropanolamine - Wikipedia

Solubility: dissolution in any protic solvent will result in solvolysis of the reagent; dissolution in polar aprotic solvents could result in dehydration or destruction of the solvent; polyphosphoric acid is neither soluble in nor reacts with nonpolar organics such as toluene or hexane.

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