Estudo semi-empírico de ácidos hidroxâmicos: ácido formoidroxâmico e derivados do aleloquímico dimboa

Química Nova

Carlos Mauricio R. Sant'anna¹  Vivian Passos De Souza¹ 

[1] ,Universidade Federal Rural do Rio de Janeiro ICE Departamento de QuímicaSeropédica RJ

关键词: semiempirical;    hydroxamic acids;    acidity;   

DOI  :  10.1590/S0100-40422001000500002

来源: SciELO

【 摘 要 】

Open chain hydroxamic acid (Hx) can exist as Z and E diastereomers of two tautomers, hydroxamic acid and hydroximic acid. The conformational stability of the formohydroxamic acid isomers evaluated by PM3 compared better to ab initio results from the literature than AM1 results. Structural data of the cyclic Hx 2,4-dihydroxy-7-metoxy-2H-1,4-benzoxazin-3(4 H)-one (DIMBOA) obtained by both semiempirical methods compared well to ab initio results. pKa data from the literature for derivatives of the aldolic isomer of DIMBOA were compared to the stability of the anions resulting from the loss of protons of their phenol and hydroxamic acid groups, determined as the difference in heat of formation between anionic and neutral forms, calculated by AM1 and PM3 methods. Good correlations between theoretical and experimental data were obtained for both semiempirical methods.

【 授权许可】

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