Code:
$ cat samp.txt
1,abc,def,1234,A *
2,bed,dec,342,* A
3,dec,345,23,*&^
4,sdf,fgh,234,
5,ert,345,ghj,C*2
6,ert,345,sdf,123
$ awk -F, '{if ($NF ~ /[0-9]$|[A-Za-z]$/) {print >"goodfile"} else {print >"badfile" }}' samp.txt
$ cat goodfile
2,bed,dec,342,* A
5,ert,345,ghj,C*2
6,ert,345,sdf,123
$ cat badfile
1,abc,def,1234,A *
3,dec,345,23,*&^
4,sdf,fgh,234,