腈钠
腈钠是指腈类化合物和钠离子形成的盐，这类盐被认为是反应中存在的中间体。腈钠可由腈和氨基钠、取代氨基钠或金属钠反应得到。但由于腈钠的高度不稳定性，其固体的分离特别困难。[1]
乙腈钠
乙腈钠（NaCH2CN，Mr＝63.0）被认为是一种白色固体，可由乙腈和NaN(SiMe3)2反应得到：[2]
- CH3CN + 3 NaN(SiMe3)2 —乙醚→ NaCH2CN + HN(SiMe3)2 + 2 NaN(SiMe3)2
该反应中，乙腈只有1个氢原子被钠取代。
由于乙腈的α-H具有一定的酸性，因此与氨基钠在液氨中反应，生成了一种被认为是NaCH2CN·xNH3或(CH2CN)-Na+·xNH3的产物。但当这种化合物在液氨中结晶时，产生的却是CH3C(=NH)NHNa（脒的钠盐）。[3]
乙腈钠可以和卤代烃反应：
- NaCH2CN + RX → NaX + RCH2CN
苯乙腈钠
苯乙腈钠（C16H13N2Na，Mr＝256.3）可由苯乙腈和金属钠直接反应得到，其产物为二聚体的钠盐：[1]
- 3 C6H5CH2CN + 2 Na → NaCN + C6H5CH3 + C16H13N2Na
Fred等认为苯乙腈钠的结构应该是(C6H5)HC=C=N-Na（Mr＝139.1）[4]：
- 2 (C6H5)H-C=C=N-H + 2 Na → 2 (C6H5)H-C=C=N-Na
- (C6H5)H-C=C=N-Na + H2 → C6H5CH3 + NaCN （副反应）
- 2 (C6H5)H-C=C=N-Na → NaCN + (C6H5)H-C=C-H(C6H5)
它和空气中的氧气反应，得到苯甲酸和氰化钠：
- 2 (C6H5)H-C=C=N-Na + O2 → C6H5COOH + NaCN
腈的其它金属盐
苯乙腈和钾的反应可以得到相应的钾盐，反应按如下方程式发生：[5]
- 2 C6H5CH2CN + 2 K → 2 C6H5HC=C=NK + H2
产物C6H5HC=C=NK对水蒸气和二氧化碳敏感，酸会将其分解，放出氰化氢。它和(C6H5)(CN)HCK有着互变异构，虽然该异构体不占主导，但能够和碘乙烷反应，产生该异构体的取代物：
- (C6H5)(CN)HCK + C2H5I → (C6H5)(CN)HC(C2H5) + KI
腈的镁、铜[6]、锌盐[7]也被制得，它们和钠盐一样，都是很强的亲核试剂。这些腈的金属盐中碳氮键的三键性质之外，通过X射线分析，还有部分碳碳双键的性质。[8]
参考文献
- ^ 1.0 1.1 Mary M. Rising, Tsoh-Wu Zee. SODIUM SALTS OF AROMATIC NITRILES. I. J. Am. Chem. Soc., 1928, 50 (6), pp 1699–1707. DOI: 10.1021/ja01393a028
- ^ 2.0 2.1 Robert West, Gerald A. Gornowicz. Polylithium compounds. IV. Polylithiation of nitriles and the preparations of trisilyl ynamines. J. Am. Chem. Soc., 1971, 93 (7), pp 1714–1720. DOI: 10.1021/ja00736a025
- ^ F. W. Bergstrom, Robert Agostinho. The Alkylation and Arylation of Aliphatic Nitriles in Liquid Ammonia. J. Am. Chem. Soc., 1945, 67 (12), pp 2152–2154. DOI: 10.1021/ja01228a025
- ^ Fred W. Upson, Robert T. Maxwell, Howard M. Parmelee. STRUCTURE OF THE SALTS OF AROMATIC NITRILES. J. Am. Chem. Soc., 1930, 52 (5), pp 1971–1975. DOI: 10.1021/ja01368a031
- ^ Mary M. Rising, Irving E. Muskat, Edmund W. Lowe. SALTS OF AROMATIC NITRILES. II. POTASSIUM PHENYLACETONITRILE. J. Am. Chem. Soc., 1929, 51 (1), pp 262–265. DOI: 10.1021/ja01376a033
- ^ Matthew Purzycki, Wang Liu, Göran Hilmersson, et al. Metalated nitriles: N- and C-coordination preferences of Li, Mg, and Cu cations. Chem. Commun., 2013,49, 4700-4702. DOI: 10.1039/C3CC41703D
- ^ Xun Yang, Dinesh Nath, and Fraser F. Fleming. Chemoselective Alkylations with N- and C-Metalated Nitriles. Org. Lett., 2015, 17 (19), pp 4906–4909 DOI: 10.1021/acs.orglett.5b02481
- ^ Fraser F. Fleming , Zhiyu Zhang , Wang Liu, et al. Metalated Nitriles: Organolithium, -magnesium, and -copper Exchange of α-Halonitriles. J. Org. Chem., 2005, 70 (6), pp 2200–2205. DOI: 10.1021/jo047877r