Rename files matching pattern in a loop - Bash - bash

Question

I have been trying to rename some specific files based on a table but with no success. It either renames all files or gives error.
The directory contains hundreds of files named with long barcodes and I want to rename only files containing the patter _1_.
Example
barcode_1_barcode_SL484171.fastq.gz barcode_2_barcode_SL484171.fastq.gz barcode_1_barcode_SL484370.fastq.gz barcode_2_barcode_SL484370.fastq.gz
mytable.txt
oldname
newname
barcode_1_barcode_SL484171
Description1
barcode_2_barcode_SL484171
Description1
barcode_1_barcode_SL484370
Description2
barcode_2_barcode_SL484370
Description2
Desire output:
Description1.R1.fastq.gz Description2.R1.fastq.gz
As you can see in the table there are two files per description but I only want to rename the ones with the _1_ pattern.
Code I have tried:
for i in *_1_*.fastq.gz; do read oldname newname; mv "$oldname" "$newname".R1.fastq.gz; done < mytable.txt
for i in $(grep '_1_' mytable.txt); do read -r oldname newname; mv ${oldname} ${newname}.R1.fastq.gz; done < mytable.txt
for i in $(grep '_1_' mytable.txt); do oldname=$(cut -f1 $i);newname=$(cut -f2 $i); ln -s ${oldname} ${newname}.R1.fastq.gz; done

Answer 1

while read -r oldname newname
do
if [[ $oldname =~ "_1_" ]]
then
mv $oldname $newname
fi
done < mytable.txt

Answer 2

Something like this.
#!/usr/bin/env bash
while IFS= read -r files; do ##: loop through the output of `grep 'barcode_1_barcode.*' table.txt`
while read -ru9 old_name prefix; do ##: loop through the output of `find . -name 'barcode_1_barcode*.gz' | grep -f <(cut -d' ' -f1 table.txt`
if [[ $files == *"$old_name"* ]]; then ##: If the filename from the output of find matches the first field of table.txt (space delimite)
old_filename="${files%.fastq.gz}" ##: Extract the filename without the fast.gz extesntion
extension="${files#"$old_filename"}" ##: Extract the extention .fast.gz without the filename
# mv -v "$files" "$prefix.R1${extension}"
printf '%s %s %s ==> %s\n' mv -v "$files" "$prefix.R1${extension}" ##: Rename the files to the desired output
fi
done 9< <(grep 'barcode_1_barcode.*' table.txt)
done < <(find . -name 'barcode_1_barcode*.gz' | grep -f <(cut -d' ' -f1 table.txt) ) ##: Remain the first column/field of table.txt
Output from the OP's sample data/files.
renamed './barcode_1_barcode_SL484370.fastq.gz' -> 'Description2.R1.fastq.gz'
renamed './barcode_1_barcode_SL484171.fastq.gz' -> 'Description1.R1.fastq.gz'
If you're satisfied with the output either move the # from the front of mv to the
front of printf or just delete the entire line with printf and remove the # from
mv in order for mv to actually rename the files.