Density Functional Study of the Reaction Mechanism of Two Oxiimine Alcohol Formations and Their Novel Rearrangements

Abstract

In this study, the reaction mechanisms of isonitrosoacetophenone (inapH) with ethanolamine (ea) and 1‐phenylethanolamine (pea) have been investigated theoretically using B3LYP/6‐311G(d,p) method to explain why the formation and unexpected rearrangement products occur or not occur. While the reaction between isonitrosoacetophenone (inapH) with ethanolamine gives oximine alcohol (Ib), the reaction of 1‐phenylethanolamine with inapH results in the formation of oximine alcohol with a different substituent (Ia) and amido alcohol (IIa), which is the unexpected rearrangement product. The rearrangement driving forces of compounds from Ia to IIa are calculated as ca. 28 and 23 kJ/mol in the gas and EtOH phases, respectively. These driving forces have been calculated ca. 46 and 45 kJ/mol for the rearrangement of compound Ib to obtain IIb in the same phases, respectively. This high driving force shows that the compound IIb cannot be obtained from rearrangement of compound Ib as described experimentally in the literature. In addition, as the DFT functionals poorly describe dispersion effects, dispersion correction for reaction heat and free‐energy barrier was estimated using the wB97X‐D/6‐311G(d,p). In general, the relative free energies of all molecules calculated from wB97XD method are lower than performed from B3LYP level. The changes of thermodynamic properties for all molecules with temperature ranging from 100 to 500 K have been obtained using the statistical thermodynamic method.

Quantum Chemical Studies of the Substituent Effect on the Reaction of Carbonyl Oxime with Amine

“…40,41 Then, these reaction mechanisms were performed theoretically by our group. 28 In this section, the suggested reaction mechanism was studied theoretically for synthesizing four different molecules (I−IV). In all of the calculations, a Lenovo Thinkstation D20 workstation and the GAUSSIAN 03 program package were used.…”

“…In our previous study, the reactions between isonitrosoacetophenone (inapH) and two different substitue amines, pea and ea, were studied experimentally. , Then, these reaction mechanisms were performed theoretically by our group . In this section, the suggested reaction mechanism was studied theoretically for synthesizing four different molecules ( I – IV ).…”

“…Synthesis. All compounds were prepared by the methods in our previous study, 28 and details on the synthesis and characterization by elemental anaylsis and IR and NMR spectra are presented in the Supporting Information.…”

“…Recently, DFT studies of the reaction mechanism of two imine oximes, namely, (3E)-3-aza-5-(hydroxyimino)-1,4-diphenylpent-3-en-1-ol and (1E,2E)-[(2-hydroxyethyl)imino]-2-phenyl-ethanal oxime, and their novel rearrangements were performed by our group. 28 In this study, two different products obtained experimentally in the literature were modeled by DFT, and the dispersive effects were studied. The reaction mechanism was suggested for these two products.…”