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研究了一系列5-乙氧羰基-4-取代-6-甲基-3,4-二氢嘧啶-2(1H)-酮的电子轰击飞行时间质谱,建立了此类化合物的裂解方式和分子离子峰的强度规律.利用飞行时间质谱的中分辨能力,测得了各碎片离子的精确质量,这些数据经OpenLynx软件导出所有分子离子和碎片离子的元素组成.根据质谱裂解规律,主要质谱离子得到了归属.两类主要裂解途径为:对所有标题化合物,通过失去4位上的R1,酯基上的C2H4(麦氏重排)和H2O(通过环状六员过渡态)形成三种阳离子;对4-芳基化合物,通过失去EtCO2形成另一类阳离子.此外,还提出了个别化合物的一些重要裂解行为.
A series of 5-ethoxycarbonyl-4-substituted-6-methyl-3,4-dihydropyrimidin-2 (1H) -ones was studied by electron impact time of flight mass spectrometry. The intensity of the ion peaks.The accurate mass of each fragment ion was measured by the mid-resolution ability of time-of-flight mass spectrometry, and the data of all the molecular ions and fragment ions were derived by OpenLynx software.According to the rule of mass spectrometry cleavage, Two main classes of cleavage approaches are: For all the title compounds, three cations are formed by the loss of Rl at position 4, the C2H4 (Mylar rearrangement) on the ester group, and H2O (via the ring six-member transitional state); The 4-aryl compounds formed another type of cation by the loss of EtCO 2. In addition, some important cleavage behavior of individual compounds was also proposed.