2-Quinoxalinyl thiocyanate (1) possesses four electrophilic sites, i.e., 2-position, 3-position, sulfur and cyano carbon, to receive nucleophilic attack.Grignard reagents attacked preferentially the sulfur atom to give sulfides (8-12).These sulfides were readily oxidazed to sulfoxides (13-17) with sodium bromite in acetic acid.Hydroxide and ethoxide ions were found to attack preferably the cyano carbon to give thiol (2), while amines (butylamine, piperidine and morpholine) and ethyl cyanoacetate carbanion attacked the carbon at the 2-position to afford the corresponding ipso-substitution products (4-7).
2-
喹啉基
硫氰酸酯(1)具有四个亲电位点,即2位、3位、
硫和
氰碳,可以接受亲核攻击。格林纳德试剂优先攻击
硫原子,形成了
硫化物(8-12)。这些
硫化物在
醋酸钠溴酸盐的作用下很容易被氧化为亚砜(13-17)。羟基和乙氧基离子优先攻击
氰碳,生成
硫醇(2),而
胺类(
丁胺、
哌啶和吗啉)和乙基
氰乙酸阴离子则攻击2位碳,生成相应的近位取代产物(4-7)。