Thermogravimetrical investigations of the dealkoxycarbonylation of N-acyl-α-triphenylphosphonioglycinates

Thermogravimetrical experiments revealed that immediately after the endothermic process of the melting of N-acyl-α-triphenylphosphonioglycinates 1, an exothermic demethoxycarbonylation of phosphonioglycinates commenced, accompanied by the release of CO 2. The residues contained the corresponding N-a...

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Bibliographic Details
Published in:Thermochimica acta 2011, Vol.512 (1), p.22-27
Main Authors: Adamek, Jakub, Mrowiec-Białoń, Julita, Październiok-Holewa, Agnieszka, Mazurkiewicz, Roman
Format: Article
Language:English
Subjects:
bromides
carbon dioxide
Chemistry
Dealkoxycarbonylation
Exact sciences and technology
heat production
iodides
Krapcho reaction
melting
N-Acylaminomethyltriphenylphosphonium salts
Organic chemistry
Organometalloidal and organometallic compounds
P derivatives
Preparations and properties
Thermogravimetry
Triphenylphosphonioglycinates
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Summary:Thermogravimetrical experiments revealed that immediately after the endothermic process of the melting of N-acyl-α-triphenylphosphonioglycinates 1, an exothermic demethoxycarbonylation of phosphonioglycinates commenced, accompanied by the release of CO 2. The residues contained the corresponding N-acylaminomethyltriphenylphosphonium salts 2 (18.3–49.5%), methyltriphenylphosphonium salts 7 (21.8–67.9%), and the corresponding 1,2-di( N-acylamino)fumaric acid dimethyl ester 6 (2.1–26.0%). When the reaction was carried out in the presence of Ph 3P and the corresponding triphenylphosphine hydrobromide, hydroiodide, or tetrafluoroborate, N-acyl-α-triphenylphosphoniumglycinate bromides and iodides 1a– f underwent demethoxycarbonylation to form the corresponding N-acylaminomethyltriphenylphosphonium salts 2a– f at 95–130 °C in good to excellent yields (79–100%). On the other hand, tetrafluoroborates 1g– i underwent corresponding reactions at about 170–175 °C to give phosphonium tetrafluoroborates 2g– i in much lower yields (34–67%). Plausible mechanisms of the investigated reaction are discussed. It was also demonstrated that the obtained crude α-( N-acylamino)alkyltriphenylphosphonium salts 2 could be applied as valuable α-amidoalkylating agents in spite of their contamination with inert methyltriphenylphosphonium salts 7.
ISSN:0040-6031
1872-762X
DOI:10.1016/j.tca.2010.08.017