I am designing a solution for you based upon my education and later research and practice of meditation:

Develop your ability to stay as awareness out of class and in class in a consistent basis. Read this article, it is teaching how to do this: What is meditation? How to practice meditation.

After you understand how to practice, also practice walking meditation. This will teach you to stay as awareness while doing a physical activity.

In class you can stay as awareness, and this will give you a heightened listening ability. (also an increased capacity for understanding because you are developing a less distracted mind)

Along with this heightened listening ability, you can learn to take notes as well, just like how you do it in walking meditation. (staying as awareness and physical activity together)

To be able to do this, it will require practice and development of your meditativeness/concentration ability as well as learning to do this in the actual context of listening to the class/taking notes.

Note: As a side idea, you can ask the teacher and take pictures of the board, to be able to fully concentrate on listening. But I believe practicing the above approach will help you with your goal based on your dedication. It is a very targeted approach based on your question.