How to specify multiple input files for Tesseract when using the output PDF option (only works with 'parallel' on the command line)

I am trying to tesseract all files in a directory to a pdf:

This command works fine:

ls * | parallel -j 4 tesseract {} {.} pdf

And produces a pdf for each input file.

However, I am unable to get it to work without the parallel method.

If I enter:

for i in * ; do tesseract $i $1 pdf;  done;

It doesn't produce any pdfs and instead creates a single file named pdf.txt

What is the best way create pdfs from the input files in a folder without using the parallel option.

I understand that parallel is more efficient, but I would like to have the option of running without parallel for comparison purposes. Tx!