Thioglycolic acid를 이용한 황-포함 작용기 도입에 관한 연구

Abstract

C-S bond formation is important for the synthesis of various chemicals such as pharmaceuticals, pesticides, and polymer materials. Several reagents such as H2S, NaSH, sulfur powder, etc. have been used as sulfur source for the C-S coupling. However, they have some limitations; they are highly reactive and toxic, and have unpleasant odor. Thioglycolic acid can be a complementary sulfur source for copper-catalyzed C-S bond forming reactions and the most important variable in this reaction is the solvent; polar aprotic solvents such as DMSO or DMF work best. Interestingly, several different C-S bond containing products were obtained depending on the reaction solvents. Each optimized protocol gave biaryl disulfide and 2-(phenylthio)acetic acid, respectively. Thioglycolic acid can be also used to introduce a thioformyl group into amines. Thioformyl group are often used as an intermediate of various compounds. However, its synthetic methods have been rarely reported. Toxic H2S gas or reagents of low atom economy are required to prepare thioformamides. Yet, these reagents produce a very limited variety of thioformamide. This study discovered that the introduction of thioformyl group into primary and secondary amines and aniline is possible by using of thioglycolic acid in the absence of a transition metal catalyst.