Analyse structurale des derives fonctionnels des acides carboxyliques Partie III. Acetate d'ethyle et derives α-halogenes

Article abstract of DOI:10.1016/0022-2860(91)85069-F

Methylene bending mode analysis of ethyl esters of acetic and haloacetic acids XCH2CO2C2H5 where X=H(I), F(II), Cl(III), Br(IV) and I(V) reveals that in the dissolved state (CCl4) these compounds have conformations induced by rotating motion of the XCH2 and C2H5 groups ( (II), (III) and (IV) ) or by C2H5 group rotation exclusively ( (I) and (V) ).In the last case, (I) exists in gauche and anti conformations while (V) occurs in gauche-gauche and gauche-anti conformations.A theoretical study of compounds (I), (II) and (III) by the PCILO method and Onsager formalism leads to the following conclusions.The conformers of (I) have a dihedral angle (H3)C-C(H2)-O-C of 70 deg (gauche conformer) and 180 deg (anti conformer).For (II) and (III), there are four stable conformers whose dihedral angles φ3=(H3)C-C(H2)-O-C and θ=X-C-C=O values are in agreement with C2H5 and CH2X group orientations found in experimental analysis.