Quinoxalines. XXVI. Reactions of 2-quinoxalinyl thiocyanate with nucleophiles.
作者:Chihoko IIJIMA、Tomiko KYO
DOI:10.1248/cpb.37.618
日期:——
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).