OT;
some line
/*asas*/        ##here comments should be removed
/*asdas*/  #OT;.....RT;should be replaced with OT;.....DT;OT.......RT;
some line
RT;

some lines 
somlelines

OT;
some line
/*asas*/
/*asdas*/
some line
RT;

what i need is like 

OT;
some line1
some line2
DT;
OT;
some line1
some line2
RT;

some lines3 
somlelines4

OT;
some line5
some line6
DT:
OT;
some line5
some line6
RT;

if($string=$string=~ s/OT;(.*?)(/*(.*?)*/)*(.*?)RT;/OT;$1$4DT;\nOT;$1$4RT;/gsr)
{
	       print "modified string".$string;
	    }