A compound having the structure wherein R is an angiotensin receptor antagonist active group, and Y is Y is selected from the group consisting of R1 is selected from the group consisting of —O—C1-6 alkyl, —O-aryl, —O-heteroaryl, —O—C3-8 cycloalkyl, —C1-6 alkyl, -aryl, -heteroaryl, and —C3-8 cycloalkyl; R2 and R3 are independently selected from the group consisting of hydrogen and C1-4 alkyl, or a pharmaceutically acceptable salt or hydrate thereof, which is useful for treating hypertension.