Alpha2-adrenoreceptors profile modulation. 3.1 (R)-(+)-m-nitrobiphenyline, a new efficient and alpha2C-subtype selective agonist

To assess the stereochemical requirements for efficient R2C-adrenoreceptor activation, the enantiomeric forms of m-nitrobiphenyline [(()-5] were prepared and tested on cells expressing the human R2-adrenoreceptor subtypes. The importance of chirality was confirmed, since the enantiomer (R)-(+)-5 was much more efficient than (S)-(-)-5 in producing R2C-activation. Surprising reversal of enantioselectivity was observed with respect to structurally similar biphenyline [(()-1] whose (S)-(-)-form proved the preferred R2C-configuration