Molecular Modeling and Synthesis of Ethyl Benzyl Carbamates as Possible Ixodicide Activity

Vázquez-Valadez Víctor Hugo,Abrego Víctor,Hernández-S Manuel Alejandro,Prado-O María Guadalupe,Rosales-H María,Velázquez-S Ana María,Leyva-R Marco Antonio,Ángeles Enrique,Muñoz-G Marco Antonio,Cruz-A Diego,Alba-H Fernando

doi:10.4236/cc.2019.71001

Abstract

Carbamates are molecules that have different types of biological activities and provide a particular chemical control against ticks. The new structures of the proposed compounds were optimized and synthetized respectively, through a molecular model using the methods:PM3, HF and DFT applying the B3LYP functional, with the basis 6-31+G(d) and 6-311+G(d,p), BVP86 and PBEPBE with 6-31+G(d) and the vibrational frequencies computed. These calculated frequencies were compared with the experimental ones to determine the most accurate level of theory for the prediction of vibrational frequencies of the compounds. The best results were obtained through HF/631+G(d). Additionally, we report a modification to obtain this type of compounds, and based on the amino-dehalogenation of ethyl chloroformate, different benzyl ethyl carbamates were synthesized modifying the base molecule. The performances obtained were compared to others already reported. The methodology used allowed us to synthesize new carbamates using benzylamine derivatives through a modification on the basic catalysis of the addition-elimination reaction.

Highlights

A 3% is arbitrary defined as the maximum objective error, the HF method has the lowest error (80.00% of computed frequencies under 3% error), followed by B3LYP/6-31+G(d), B3LYP/6-311+G(d,p) and PBEPBE/631+G(d) with 68.5%, 65.71% and 62.86% respectively
The results showed that both DFT/B3LYP are the best methods to describe atomic charges despite their geometric optimization are not the best
The level of theory HF/6-31+G(d) was calculated with the intention of providing closer values to the experimental ones (%EAbs = 1.88% ± 0.26%, RMSov = 32.88 ± 0.23 cm−1) and requiring less time for the computational procedure, which is the best prediction of vibrational frequencies of the synthesized compounds

Summary

Introduction

(Boophilus microplus), which is a hematophagous parasite that represents a great threat for cattle industry, because of the diseases it causes, and for the huge economic loss it brings [1]. These losses are due to: Skin damage caused by parasite bites while feeding themselves (affecting negatively on the consumption value), anemia, transmitted pathologies, less food intake with consequential weight loss of cattle (0.6 g per each adult tick; between 40 and 60 Kg of live weight per year), and it diminishes milk and meat production; plus the extra costs for treatment on the affections caused by transmitted pathogens [2]. Brazil, 1963; Argentina, 1964; Colombia, Venezuela, 1967; South Africa, 1979; Uruguay, 1983; México, 1986

Results

Discussion

Conclusion