Crystal and molecular structures of 1-isoquinolyl(phenyl)methyl benzoate and 1-isoquinolylisopropyl benzoate

Both of the title compounds crystallize in the monoclinic system: C₂₃H₁₇NO₂ (Ib),P2₁/c,a = 8.970(1),b = 22.629(5),c = 9.101(1) Å, = 106.08(1) °,Z = 4,D _x = 1.27 Mg m^–3; C₁₉H₁₇NO₂ (Ic),P2₁/a,a = 15.225(2),b = 6.429(1),c = 17.190(1) Å, = 112.99(1) °,Z = 4,D _x = 1.25 Mg m^–3. The structures were solved and refined by standard methods, both toR 0.04. In compound Ib, a weak intramolecular interaction is observed between the nitrogen atom from the isoquinoline ring and the carbon atom from the carbonyl group, with the N(2) . C(18)distance being 2.98 Å. In compound Ic, the PhCO₂ -fragment is twisted in the opposite direction to that in compound Ib, without hydrogen bonding. The pK _a and IR data were considered in the light of the results of the X-ray investigation.