Mechanistic evaluation of carbodiimides by mass spectrometry

• Grant number: 19/22047-5
• Support Opportunities: Scholarships in Brazil - Master
• Start date: March 01, 2020
• End date: September 30, 2021
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Physical-Chemistry
• Principal Investigator: Thiago Carita Correra
• Grantee: Eric Lobato Graef
• Host Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 14/15962-5 - Reaction mechanism of asymmetric catalysts by mass spectrometry and gas-phase vibrational ion spectroscopy, AP.JP

Abstract

This project aims to evaluate the mechanisms of carbodiimide mediated reactions, focusing on the quinazoline formation induced by the in situ generation of carbodiimides from thiourea. To do so, advanced mass spectrometry techniques will be used to allow not only the identification of reaction intermediates but also to characterize the nature of the observed species by the ion vibrational IRMPD spectroscopy technique recently implemented in Brazil by our research group. On-line methodologies will be used to allow real-time following of reaction intermediates using primarily the pressurized sample injection (PSI) and other in-flow methods that allow the evaluation of shorter lifetime intermediates. Natively charged carbodiimides obtained by metilation of a tertiary amine 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide will be used as charged tags to allow following neutral intermediates and reactive species, enhancing their detection limits. The peptide bond formation reaction mediated by carbodiimide, already characterized in the literature, will be used to verify the suitability of the charge tag use for the study of reaction intermediates, as the native charge may influence the reaction mechanism under evaluation. The same system will also be employed to test the experimental apparatus used for the real-time analysis of intermediates. Finally, the reaction intermediates observed and the proposed mechanisms will be modeled by electronic structure calculations using the density functional theory (DFT). (AU)

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

GRAEF, Eric Lobato. Mechanistic Evaluation by Mass Spectrometry and Computational Modeling of the Reaction Between 2ABP and Thiourea for Formation of 4-phenilquinazoline. 2022. Master's Dissertation - Universidade de São Paulo (USP). Conjunto das Químicas (IQ e FCF) (CQ/DBDCQ) São Paulo.