- Synthesis and Structure of Alkyl N-Acylimidates
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Alkyl N-acylimidates 1 are prepared more easily and in higher yields than before by reaction of alkyl imidate hydrochlorides 5 with acyl halides 7 in the presence of 2.2 mol of base (14 examples).The X-ray analysis of a crystalline derivative (1dbd) shows, that the C=N- and C=O parts are twisted significantly (torsional angle 77.6 deg).The stereochemical, dynamic and electronic properties of the compounds 1 are interpreted by means of ab initio 3-21 G calculations on conformers of the parent system HO-CH=N-CH=O (8).Low rotational (ca. 6 kcal/mol) and inversional (max. 8 kcal/mol) barriers indicate the many favourable electronic interactions between the C=N- and the C=O groups in such N-functionalised imine derivatives.The compound 1 are significantly higher in energy than bisacylamines and are therefore suggested to be superior, more reactive synthetic C-N-C building blocks.The spectroscopic properties (IR, 13C- and 1H NMR, MS) are given and discussed.
- Kupfer, Rainer,Nagel, Michael,Wuerthwein, Ernst-Ulrich,Allmann, Rudolf
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p. 3089 - 3104
(2007/10/02)
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