Piperazinyl benzamidines were prepared and found to bind to the rat delta (
delta) opioid receptor. The most active compounds had a N,N-diethylcarboxam
ido group and N-benzyl piperazine. The most potent among these was N,N-diet
hyl-4-[4-(phenylmethyl)-1 -piperazinyl][2-(trifluoromethyl)phenyl]iminometh
yl]benzamide (27) with a 1.22 nM K-i for the rat delta opioid receptor and
ca. 1000x selectivity relative to the mu opioid subtype. (C) 2001 Elsevier
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