Synthesis of (+/-)-2-O-[4'-(N-9''-purinyl)butyl] myo-inositol 1,4,5-tris(phosphate), a potent full agonist at the D-myo-inositol 1,4,5-tris(phosphate) receptor.

Racemic 2-O-[4'(9''-N-purinyl)butyl] myo-inositol 1,4,5-tris(phosphate) 8 was synthesized starting from myo-inositol. Substitution of position 2 by an alkyl side chain was rendered possible by inversion of the chair conformation of the inositol ring by means of an orthoester. The final compound is a full agonist with the same order of potency as d-myo-inositol 1,4,5-tris(phosphate).

Synthesis and binding properties of cyclopentane analogues of myo-inositol 1,4,5-tris(phosphate).

Cyclopentanic analogues of myo-inositol 1,4,5-tris(phosphate) were synthesised starting from cyclopentadiene. The affinities of the trisphosphorylated derivatives for the Ins(1,4,5)P(3) receptors were equipotent to that of compound 4, showing that the relative orientation of the functional groups, particularly of the hydroxyl, is not of prime importance in this series. The (31)P NMR titration curves show that the tris(phosphate) 5 behaves as the superimposition of an independent phosphate and a vicinal bis(phosphate).