Theoretical study of the mechanism of 2,5-diketopiperazine formation during pyrolysis of proline

Abstract

estoy de acuerdo con su contenido, por lo que los derechos de propiedad intelectual del presente trabajo quedan sujetos a lo dispuesto en esas Políticas.Asimismo, autorizo a la USFQ para que realice la digitalización y publicación de este trabajo en el repositorio virtual, de conformidad a lo dispuesto en el Art.

Theoretical Calculations of the Multistep Reaction Mechanism Involved in Asparagine Pyrolysis Supported by Degree of Rate Control and Thermodynamic Control Analyses

“…Sharma et al [12] generalized the formation of 2,5-diketopiperazine (DKP) products based on the pyrolysis reaction of some amino acids, such as proline and glycine, describing a reaction with two main processes: a dimerization and a cyclization [12]. The mechanism involved in this process was evaluated recently in detail by us [16]. The DKP mechanism (DKP mech) consists of a dimerization in the first stage, which is reached after the intermolecular condensation between a carbonyl group and an amino group, and is followed by a dehydration of the glycol group just formed.…”

“…The total electronic energy (E) over the normalized reaction coordinate (ξ) was determined from the forward and reverse IRC profile, starting from the rate-controlling transition state optimized structure. After that, the reaction force (dE/dξ = −F) was calculated from the numerical derivative of the energy with respect to the reaction, which was used to build the reaction force profile corresponding to the rate-controlling process of the selected mechanism [16,[24][25][26][27].…”

Density functional theory-based investigation of HCN and NH3 formation mechanisms during phenylalanine pyrolysis

“…Liu et al 15 studied the pyrolytic decomposition of coal pyrrole to HCN, revealing that the corresponding energy barrier is substantially reduced in the presence of hydrogen radicals. Cristian et al 16 studied the formation of 2,5-diketopiperazine during the pyrolysis of proline, showing that the transition state corresponds to the (rate-determining) dehydration process. Saleh et al 17 employed density functional theory (DFT) calculations to study the decomposition of a single proline molecule, obtaining carboxylation and dehydration energy barriers of 297.1 and 304.6 kJ mol À1 , respectively.…”