Jordan Alfonzo D, Luo Chi, Reitz Allen B
Drug Discovery Division, Johnson & Johnson Pharmaceutical Research and Development, P.O. Box 0776, Welsh and McKean Roads, Spring House, Pennsylvania 19477-0776, USA.
J Org Chem. 2003 Oct 31;68(22):8693-6. doi: 10.1021/jo0349431.
The reaction of molecular bromine (Br2) with arylthioureas is known to produce 2-aminobenzothiazoles (Hugerschoff reaction). We show here that benzyltrimethylammonium tribromide (1, PhCH2NMe3Br3), a stable, crystalline organic ammonium tribromide (OATB), can be readily utilized as an alternative electrophilic bromine source. It is easier to control the stoichiometry of addition with an OATB, which minimizes aromatic bromination caused by excess reagent. We have developed a direct procedure from isothiocyanates and amines using tetrabutylammonium thiocyanate (Bu4NSCN) and PhCH2NMe3Br3 to afford functionalized 2-aminobenzothiazoles.
已知分子溴（Br₂）与芳基硫脲反应会生成2-氨基苯并噻唑（胡格肖夫反应）。我们在此表明，苄基三甲基溴化铵（1，PhCH₂NMe₃Br₃），一种稳定的结晶有机三溴化铵（OATB），可以很容易地用作替代亲电溴源。使用OATB更容易控制添加的化学计量，这可将过量试剂引起的芳环溴化降至最低。我们已开发出一种使用四丁基硫氰酸铵（Bu₄NSCN）和PhCH₂NMe₃Br₃，由异硫氰酸酯和胺直接制备官能化2-氨基苯并噻唑的方法。
