The novel 3-ureidobenzazepin-2-ones 11 and 12, which incorporate a cat
ionic substituent at the 5-position were designed and synthesised as l
igands for the CCKB receptor. These compounds proved to have high affi
nity for the CCKB receptor and were selective over the CCKA receptor s
ubtype. This work further defines the role of the benzazepine template
as a bioisostere for the 1,4-benzodiazepine template of earlier CCK a
ntagonists.