Incorrect syntax near the keyword when

Hi

Select 
(case 
when substring($[RDR1.U_Code], 1,5) = 'U_CMax then Select 'U_Max' from Oitm  where OITM.ItemCode =  $[RDR1.ITEMCODE]
when substring($[RDR1.U_Code], 1,5) = 'U_CApple then Select 'U_Apple' from Oitm  where OITM.ItemCode =  $[RDR1.ITEMCODE]
End)

Thanks