Using folder alias in a DOS loop

This code is not finding the path specified, even when I double-quote the whole path. Is there some other escaping that DOS needs specifically for loops?

@ifexists:/pdftoolkit
FOR %%F IN (*.pdf) DO /pdftoolkit\bin\pdftk.exe "%%~nF.pdf" cat 2-end output "%%~nF_.pdf"
@ifexists:else
FOR %%F IN (*.pdf) DO /pdftoolkit_c\bin\pdftk.exe "%%~nF.pdf" cat 2-end output "%%~nF_.pdf"
@leavedoswindowopen

Whereas the aliases below are resolved just fine...

@runmode hide
@ifexists:/pdftoolkit_c
/pdftoolkit_c\bin\pdftk.exe {allfile$} cat 1-endright output {file|noext}_(+90°).pdf
@ifexists:else
/pdftoolkit\bin\pdftk.exe {allfile$} cat 1-endright output {file|noext}_(+90°).pdf

You have to use the {alias|...} code to expand aliases in MS-DOS buttons, since MS-DOS doesn't understand Opus aliases.

(In fact, this may be true for arguments to external commands in general, but I'd have to check to be sure.)

If aliases were expanded automatically in this situation, having a /S alias would make it impossible to run a DOS command like dir /S where the /S is intended to be an argument switch, not an alias.

Thx sir.