it should work. make sure you wrap the email address in quotes:
filename mailbox email
TO=('usergroup@yourdomain.com')
FROM=('NoReply <NOREPLY@yourdomain.com>')
SENDER = ('NoReply <NOREPLY@yourdomain.com>')
IMPORTANCE='HIGH'
replyto='NOREPLY@yourdomain.com'
Subject='Greetings, this is an email';
DATA _NULL_;
FILE Mailbox;
PUT "Greetings Someone,";
PUT " This is a message from a SAS.";
RUN;