高分辨高能量碰撞解离质谱法研究3-苯硫基吲哚衍生物裂解反应机理

摘要

The fragmentation mechanism of protonated 3-(phenylthio)-1H-indoles was studied by highresolution electrospray ionization-high-energy collisional dissociation mass spectrometry (ESI-HCD-MS/MS),in combination with H/D exchange experiments and density functional theory (DFT) calculation.It was shown that under the mode of HCD of the protonated ion of 3-(phenyhhio)-1H-indoles,free radical cation of 3-(substituted phenyl)-indole was obtained through phenyl nucleophilic substitution and rearrangement at C3 of the indole ring followed by elimination of mercapto free radical by homolytic cleavage of the C-S bond;indole free radical cation was obtained through 1,2-hydride shift followed by loss of thiophenyl radical by homolytic cleavage of the C3-S bond;and 3-thioxo-indole cation was obtained through 1,4-proton shift followed by loss of phenyt radical by chargeinduced heterolytic cleavage of the C5-S bond.%采用高分辨电喷雾电离-高能量碰撞解离质谱(ESI-HCD-MS/MS)技术,结合H/D交换试验和密度泛函理论计算,对3-苯硫基吲哚衍生物质子化离子的质谱裂解反应机理进行了研究.结果表明:3-苯硫基吲哚衍生物的质子化离子在高能量碰撞解离模式下,通过苯基亲核取代重排到吲哚环的C3位上,C-S键均裂丢失巯基自由基,产生了3-(取代苯基)-吲哚自由基阳离子;通过1,2-氢负离子迁移和C3一S键均裂丢失苯硫自由基,则产生了吲哚自由基阳离子;通过1,4-质子迁移和C5-S键的电荷诱导异裂,产生了3-硫代吲哚阳离子.