How to rename files in folders to foldername using batch file

Question

Could any of you help me with a problem I have with a lot of files with the same name, placed in sperate folders.
The folders are named with numbers, but the files

Answer 1

@Echo OFF

FOR /D /R %%# in (*) DO (
    PUSHD "%%#"
    FOR %%@ in ("index*") DO (
        Echo Ren: ".\%%~n#\%%@" "%%~n#%%~x@"
        Ren "%%@" "%%~n#%%~x@"
    )
    POPD
)

Pause&Exit

Tested folder structure:

C:\Users\Administrador\Desktop\Nueva carpeta (3)\123321
C:\Users\Administrador\Desktop\Nueva carpeta (3)\123321\Index.txt

C:\Users\Administrador\Desktop\Nueva carpeta (3)\123456
C:\Users\Administrador\Desktop\Nueva carpeta (3)\123456\Index.php

C:\Users\Administrador\Desktop\Nueva carpeta (3)\123456\000000
C:\Users\Administrador\Desktop\Nueva carpeta (3)\123456\000000\Index.css

C:\Users\Administrador\Desktop\Nueva carpeta (3)\654321
C:\Users\Administrador\Desktop\Nueva carpeta (3)\654321\Index.html

C:\Users\Administrador\Desktop\Nueva carpeta (3)\654321\666999
C:\Users\Administrador\Desktop\Nueva carpeta (3)\654321\666999\Index.jpg

Output:

Ren: ".\123321\Index.txt"      "123321.txt"
Ren: ".\123456\Index.php"      "123456.php"
Ren: ".\654321\Index.html"     "654321.html"
Ren: ".\000000\Index.css"      "000000.css"
Ren: ".\666999\Index.jpg"      "666999.jpg"