Theoretical Study on the Epimerization of Azlactone Rings: Keto-Enol Tautomerism or Base-Mediated Racemization?

被引：18

作者：

de Castro, Pedro P. ^{[1
]}

Batista, Gabriel M. F. ^{[1
]}

dos Santos, Helio F. ^{[1
]}

Amarante, Giovanni W. ^{[1
]}

机构：

[1] Univ Fed Juiz de Fora, Chem Dept, Campus Martelos, BR-36036900 Juiz De Fora, MG, Brazil

来源：

ACS OMEGA | 2018年 / 3卷 / 03期

关键词：

DYNAMIC KINETIC RESOLUTION; PEPTIDE-SYNTHESIS; AMINO-ACIDS; 2-ALKOXY-5(4H)-OXAZOLONES; OXAZOL-5(4H)-ONES; EQUILIBRIUM;

D O I：

10.1021/acsomega.8b00060

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

Azlactones are versatile heterocycles employed in a diversity of transformations; the main drawback of these cycles consists in the epimerization of the alpha-carbonyl stereocenter during its preparation. We hereby present a theoretical study to explain how the racemization occurs. Two hypotheses were investigated: the keto-enol tautomerism and the base-mediated racemization, through an enolate intermediate. The results showed that the latter is consistent with the experimental data and can spontaneously occur at room temperature. The same pathway was evaluated for 2-alcoxy azlactone, showing a slower epimerization ratio, consistent with the literature data.

引用

页码：3507 / 3512

页数：6

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