Gamma emitting, CCK-A antagonists for pancreatic imaging

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed toward radiolabelled compounds of Formula I: ##STR2## wherein: A is ##STR3## R.
sup.
1 is H, C.
sub.
1 -C.
sub.
6 linear or branched alkyl, (CH.
sub.
2).
sub.
n COOR.
sup.
8, (CH.
sub.
2).
sub.
n OH, (CH.
sub.
2).
sub.
n CN, (CH.
sub.
2).
sub.
n NR.
sup.
9 R.
sup.
10, ##STR4## R.
sup.
2 is H, --OH, --NO.
sub.
2, F, Cl, SO.
sub.
3 H, loweralkyl, loweralkoxy, (CH.
sub.
2).
sub.
p COOR.
sup.
8 or (CH.
sub.
2).
sub.
p NR.
sup.
9 R.
sup.
10 ; R.
sup.
3, is H, --OH, --NO.
sub.
2, CF.
sub.
3, F, Cl, loweralkyl, or loweralkoxy; R.
sup.
4 is H, --OH, --NO.
sub.
2, CF.
sub.
3, CN, F, Cl, loweralkyl, loweralkoxy, (CH.
sub.
2).
sub.
p COOR.
sup.
8 or (CH.
sub.
2).
sub.
p NR.
sup.
9 R.
sup.
10 ; R.
sup.
5, R.
sup.
6 and R.
sup.
7 are, independently, H or a radionuclide selected from the group consisting of .
sup.
122 I, .
sup.
123 I, .
sup.
125 I, .
sup.
131 I, .
sup.
75 Br, .
sup.
77 Br, .
sup.
82 Br, .
sup.
211 At, with the proviso that at least one of R.
sup.
5, R.
sup.
6 and R.
sup.
7 is not H; R.
sup.
8 is H or loweralkyl; R.
sup.
9 and R.
sup.
10 are, independently, H or loweralkyl; n is 1-4; m is 1-2; p is 0-4; or pharmaceutically acceptable salt thereof.
As used herein, the definition of each expression, e.
g.
m, n, p, loweralkyl, etc.
, when it occurs more than once in any structure, is intended to be independent of its definition elsewhere in the same structure.
In the compounds of the present invention, the components having asymmetric centers occur as racemates, racemic mixtures, and as individual diastereomers, with all isomeric forms generally being included in the present invention.
In particular, the preferred stereochemistry for CCK-A antagonism relates to D-tryptophan, where C-2 and N 4 of Formula I correspond to the carbonyl carbon and .
alpha.
-amino nitrogen of D-tryptophan and --NHCOA occupies the position of the indolylmethyl side chain.
As used herein, loweralkyl is 1-7 carbon straight or branched chain alkyl and includes methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, t butyl, sec-butyl, pentyl, hexyl, and heptyl; in loweralkoxy, the alkyl portion is lower alkyl as previously defined