The electrochemically induced rearrangement of S-arylthiocarbamates to O-arylthiocarbamates
Process for the electrochemical synthesis of thiophenols from phenols
Thiophenols and their derivatives are extremely important starting materials in organic synthesis and, due to their diverse industrial applications, it is hard to imagine everyday life without them. In particular, they are essential building blocks for the synthesis of pharmaceutically important substances. They are also used as masticating agents in the rubber industry and as additives for lubricants.
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During the so-called Newman-Kwart rearrangement, an intramolecular aryl migration of O-thiocarbamates at high temperatures leads to S-thiocarbamates. The reaction thus makes it possible to produce thiophenols from phenols. However, this synthesis process is a thermal process that has disadvantages. For example, unwanted by-products or side reactions occur at high temperatures. In addition, the products hardly settle solubly on the reactor walls. It is also assumed that the energy efficiency of thermal processes needs to be improved.
The present innovation represents a process that allows the synthesis of thiophenols and its derivatives by electrochemical means at room temperature and room pressure (see scheme). The invention represents the key step (B → C) in the three-step synthesis of thiophenols (D) starting from the more accessible phenols (A). In particular, this process exhibits high energy efficiency, since the reactions occur energetically selectively and thus a high energy conversion can take place. In addition, all the disadvantages and the very complex requirements of thermal and photochemical processes are avoided. By-products and synthesis waste can be avoided with the present invention. The process according to the invention can be operated in batch and flow-through mode. Only an undivided electrochemical batch cell or a flow cell and a low-cost power supply are required. Another advantage of the innovation is that the process is scalable and can consequently also be used in industry for the production of larger quantities.
- high savings potentials and efficiency increases compared to the classic, thermally induced variant.
Scope of application
Chemistry and biotechnology, process engineering
Companies are being sought for commercial use as well as for development cooperation.
- PCT pending
- DE pending