It might be a good idea to regularly confront him with the things he says about other employees (in a subtle way), in front of those other employees, and thereb

It might be a good idea to regularly confront him with the things he says about other employees (in a subtle way), in front of those other employees, and thereby creating an uncomfortable situation that he has to handle. By doing so other employees will then become to know what you already know, and some solution is more likely to arise. In any case, before this thing starts impacting your mood outside of work, definitely leave the company. (i have been in the exact same situation and regret not leaving that company much earlier.)