Copper(II) complexes of pentadentate 17-membered macrocyclic diamidodiamines with N, O or S as additional donors.

The crystal structures of (2,6-dioxo-1,4,7,11,14-pentaazacycloheptadecanato)copper(II) tetrahydrate, [Cu(C(12)H(23)N(5)O(2))].4H(2)O, (I), (3,16-dioxo-1-oxa-4,8,11,15-tetraazacycloheptadecanato)copper(II) pentahydrate, [Cu(C(12)H(22)N(4)O(3))].5H(2)O, (II), and (3,16-dioxo-1-thia-4,8,11,15-tetraazacycloheptadecanato)copper(II) trihydrate, [Cu(C(12)H(22)N(4)O(2)S)].3H(2)O, (III), are reported. The coordination geometry in each case is approximately square pyramidal with two amine groups and two deprotonated amide groups in the basal plane. The apical position is occupied by an amine group, an ether O atom or a thio S atom. Trigonal distortion increases in the sequence S < O < N as apical donor. The relation between the distortion in the basal plane of the complexes and the maxima in their electronic spectra is discussed.

5'-Deoxy congeners of 9-(3-amido-3-deoxy-beta-D-xylofuranosyl)-N(6)-cyclopentyladenine: new adenosine A(1) receptor antagonists and inverse agonists.

The synthesis and structure-activity relationship of N(6)-cyclopentyl-3'-substituted-xylofuranosyladenosine analogues with respect to various adenosine receptors were explored in order to identify selective and potent antagonists and inverse agonists for the adenosine A(1) receptor. In particular, the effects of removal of the 5'-OH group and introduction of selected substituents at the 3'-NH(2) position of 9-(3-amino-3-deoxy-beta-D-xylofuranosyl)-N(6)-cyclopentyladenine were probed. A solid phase-assisted synthetic approach was used to optimize the 3'-amide functionality. In view of the general concern of the presence of a 5'-OH moiety with regard to cellular toxicity, the present study describes 5'-deoxy compounds with reasonable affinity for the human adenosine A(1) receptor. Interestingly, this study shows that optimization of the 3'-"up" amide substituent can substantially compensate for the drop in affinity for the adenosine A(1) receptor, which is generally observed upon removal of the 5'-OH group. The fact that for several 3'-amido-substituted (5'-deoxy)-N(6)-cyclopentyladenosine derivatives, guanosine 5'-triphosphate-induced shifts in K(i) values were significantly lower than 1 implies that these analogues behave as inverse agonists. This is further supported by their 1,3-dipropyl-8-cyclopentylxanthine-like capacity to increase forskolin-induced adenosine cyclic 3',5'-phosphate production.