Aryl acetylene inhibitors for cytochrome P450-based monooxygenase isozymes

The structures of 1-propynylpyrene (1), 4-ethynylbiphenyl (2), 3-ethynylphenanthrene (3), 9-propynylphenanthrene (4) and 9-ethynylphenenthrene (5) have been determined using MoK alpha radiation. 1 crystallizes in the monoclinic space group P2(1)/n with a = 8.972(2), b = 10.136(2), c = 14.060(2) Angstrom, beta = 99.77(1)degrees, V = 1260.0(7) Angstrom(3), Z = 4. Refinement of 1261 reflections gave R = 0.042 and R-w = 0.054. 2 crystallizes in the orthorhombic space group Pbcn with a = 17.7159(9), b = 6.250(2), c = 18.544(2) Angstrom, V = 2053(1) Angstrom(3), Z = 8. Refinement of 1710 observed reflections gave R = 0.046 and R-w = 0.053. 3 crystallizes in the orthorhombic space group Pbca with a = 7.891(1), b = 16.459(1), c = 16.879(2) Angstrom, V = 2192.2(7) Angstrom(3), Z = 8. Refinement of 1520 observed reflections gave R = 0.032 and R-w = 0.047. 4 crystallizes in the orthorhombic space group P2(1)2(1)2(1) with a = 5.8867(6), b = 13.476(1). c = 14.838(2) Angstrom, V = 1177.1(4) Angstrom(3), Z = 4. Refinement of 1217 observed reflections gave R = 0.041 and R-w = 0.055. 5 crystallizes in the monoclinic space group P2(1)/c with a = 27.755(7), b = 5.1447(9), c = 15.500(2) Angstrom, beta = 105.53(2)degrees, Z = 2133(2) Angstrom(3), Z = 8. There are two independent molecules in the unit cell. Refinement of 1276 observed reflections gave R = 0.061 and R-w = 0.065. In 2-5 there are no significant intermolecular interactions while in 1 the molecules are associated in pairs via pi-pi stacking interactions. Bond distances within the pyrene and phenanthrene portions of the molecules compare favorably with those found in other derivatives.