A compound of formula (1)
wherein X is H or —OCR
1
and Y is H or —OCR
2
, provided that X and Y are not both H; and R is CH
2
OR
9
, CONR
11
R
12
, CN, tetrazole or COOR
17
; or a salt thereof, has therapeutic utility.
公式(1)的化合物,其中X为H或—OCR1,Y为H或—OCR2,但X和Y不能同时为H;R为CH2OR9,CONR11R12,CN,
四唑或COOR17;或其盐,具有治疗效用。