alias referencing command 'echo $ORACLE_SID|tr[A-Z][a-z]' throws an error

. bash_profile contents

[oracle@<REMOVED> ~]$ cat .bash_profile

# .bash_profile

# Get the aliases and functions

if [ -f ~/.bashrc ]; then

  . ~/.bashrc

fi

# User specific environment and startup programs

export EDITOR=vi

export ORACLE_SID

export ORACLE_BASE=/u01/app/oracle

#export ORACLE_HOME=$ORACLE_BASE/product/12.2.0/dbhome_1

export ORACLE_HOME=$ORACLE_BASE/product/19.3.0/dbhome_1

export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$ORACLE_HOME/lib

export PATH=/u01/app/oracle/product/19.3.0/dbhome_1/bin:$PATH

export DIAG_TRACE=$ORACLE_BASE/diag/rdbms/'echo $ORACLE_SID|tr[A-Z][a-z]'/${ORACLE_SID}/trace

export ALERT_LOG=$DIAG_TRACE/alert_${ORACLE_SID}.log

alias diag="cd $DIAG_TRACE"