Gas Chromatography–Mass Spectrometry of Trimethylsilylated Imino Derivatives of Alanine
作者:Katsuhiro Kawashiro、Shiro Morimoto、Hideyuki Yoshida
DOI:10.1246/bcsj.58.1903
日期:1985.7
Trimethylsilylation of seven imino derivatives of alanine with N,O-bis(trimethylsilyl)trifluoroacetamide in acetonitrile was studied. The imino derivatives include 2,2′-iminodipropionitrile (1), 2,2′-iminodipropionamide (2), 2,2′-iminodipropionic acid (3), 2-(1-cyanoethylamino)propionamide (4), 2-(1-cyanoethylamino)propionic acid (5), 2-(1-carbamoylethylamino)propionic acid (6), and 3,5-dimethyl-2,6-piperazinedione (7). The reaction products were identified by gas chromatography–mass spectrometry. Under the present reaction conditions (at 100 °C for 30 min), hydrogen atoms of carboxyl and carbamoyl groups and an imide hydrogen were readily replaced by the trimethylsilyl (TMS) group, but imino hydrogens were not replaced because of the steric hindrance of N-substituent group. For the carbamoyl group, only one hydrogen was replaced. Consequently, 1 was not trimethylsilylated. Furthermore, no definite trimethylsilylation products were obtained for 4. Upon electron impact at 70 eV, 2, 3, and 5–7 gave rather simple spectra with molecular (M+) and M −15 (loss of CH3) ions characteristic of TMS derivatives. A fragment, M −117 (loss of COOTMS) or M −116 (loss of CONHTMS), was very prominent for 2, 3, 5, and 6. Other important ions such as m/z 70 were noted. Preparations and properties of some of the imino derivatives are also described.
研究了七种丙氨酸的亚氨基衍生物与N,O-bis(trimethylsilyl)trifluoroacetamide在乙腈中的三甲基硅烷化反应。这些亚氨基衍生物包括:2,2′-亚氨基双丙腈(1)、2,2′-亚氨基双丙酰胺(2)、2,2′-亚氨基双丙酸(3)、2-(1-氰乙基氨基)丙酰胺(4)、2-(1-氰乙基氨基)丙酸(5)、2-(1-氨甲酰乙基氨基)丙酸(6)和3,5-二甲基-2,6-多氟唑烷二酮(7)。通过气相色谱-质谱法识别反应产物。在当前反应条件下(100 °C,30分钟),羧基和氨甲酰基的氢原子以及内酰胺氢原子都易于被三甲基硅基(TMS)取代,但由于N-取代基的 steric hindrance,亚氨基氢原子没有被取代。对于氨甲酰基,仅取代了一个氢原子。因此,1未被三甲基硅烷化。此外,对于4未获得明确的三甲基硅烷化产物。通过70 eV的电子轰击,2、3和5-7产生了相对简单的谱图,显示出分子离子(M+)和M -15(失去CH3)峰,这是TMS衍生物的特征。对于2、3、5和6,碎片离子M -117(失去COOTMS)或M -116(失去CONHTMS)非常显著。还注意到其他重要离子如m/z 70的存在。还描述了一些亚氨基衍生物的制备和性质。