关键词: 晶体结构, 2-乙酯基-6-乙酰基吡啶, 席夫碱缩合, 小分子脂肪胺, 芳香胺, 胺解反应

A new unsymmetric compound 2-carbethoxy-6-acetylpyridine (4) was synthesized from the starting material 2,6-dimethylpyridine through four reaction steps, and then a series of 6-acetylpyridine-2-carboxamides 5～7 were prepared by the microwave irradiation from the precursor 4. These compounds have been determined by the elemental analysis, ¹H NMR, IR and MS spectra. The single crystal X-ray study of 6-acetyl-N-methylpyridine-2-carboxamide (5) indicates that 5 belongs to or-thorhombic system, Pca2(1) space group, with a＝2.2784(2) nm, b＝0.4350(4) nm, c＝0.9267(3) nm, α＝β＝γ＝90°; D_c＝1.288 Mg•m^－3, V＝0.91856(14) nm³. The experiments suggest that different types of organic amines can result in different types of reactions and products when they react with the same precursor 2-carbethoxy-6-acetylpyridine under the same conditions, i.e., aliphatic amine affords amidation while aromatic amine leads to Schiff-base condensation.

Key words: small aliphatic amine molecule, 2-carbethoxy-6-acetylpyridine, aromatic amine, crystal structure, Schiff-base condensation, amidation reaction