.gitignore match folder substring

I have folders in a project that always have .X at the end. In each of these folders, subfolders must be ignored. I am not able to get the filter to work. The .X part must be matched.

Example directory:

.git
foo/one.X/folder_to_ignore
bar/two.X/folder_to_ignore

Thins I tried, that did not work:

*.X/folder_to_ignore
*X/folder_to_ignore
**.X/folder_to_ignore
**X/folder_to_ignore
*.*.X/folder_to_ignore (regex?)

And some other variations of that sort.

Thanks.

>Solution :

Try with:

*.X/folder_to_ignore/
**/*.X/folder_to_ignore/

Let me know if it worked.