Structure of cis-1-([4-(1-imidazolylmethyl)cyclohexyl]methyl)imidazole- succinic acid complex.

CGS 14796C, C14H20N4.C4H6O4, Mr = 362.43, monoclinic, C2/c, a = 28.148 (4), b = 9.722 (1), c = 19.200 (2) A, beta = 133.06 (1) degree, V = 3838.88 A3, Z = 8, Dx = 1.26 Mg m-3, lambda (Cu K alpha) = 1.5418 A, mu 0.702 mm-1, F(000) = 1552, T = 294 K, R = 0.075 for all 3285 reflections. The structure is composed of linear chains of alternating CGS 14796C and succinic acid molecules. The CGS 14796C molecule is in an extended conformation.

Structure of (+/-)-aminoglutethimide.

(+/-)-3-(4-Aminophenyl)-3-ethyl-2,6-piperidinedione, C13H16N2O2, Mr = 232.3, monoclinic, P2(1)/n, a = 16.895 (2), b = 8.519 (1), c = 8.762 (1) A, beta = 95.71 (1) degree, V = 1254.9 (2) A3, Z = 4, Dx = 1.23 g cm-3, lambda(Mo K alpha) = 0.71069 A, mu = 0.785 cm-1, F(000) = 496, T = 294 K, R = 0.064 for all 3676 reflections. The molecule is L shaped with the p-aminophenyl and the piperidinedione groups forming the vertical arm and the base, respectively. The polar imide half of the piperidinedione group is in front of the L for the active + enantiomer and at the back for the less-active - enantiomer. The structure is very similar to that of phenobarbital. Intermolecular interactions include one strong and one weak hydrogen bond and an apparent interaction between one of the amino H atoms with the pi cloud of the phenyl ring.

Structure-activity studies of non-steroidal aromatase inhibitors: the crystal and molecular structures of CGS 16949A and CGS 18320B.

The crystal and molecular structures of 4-(5,6,7,8-tetrahydroimidazo[1,5-a]pyridin-5-yl)benzonitrile hydrochloride (CGS 16949A) and bis(p-cyanophenyl)imidazo-1-yl methane hemisuccinate (CGS 18320B) have been determined as part of structure-activity relationship studies of non-steroidal aromatase inhibitors. CGS 18320B crystallizes with two inhibitor molecules in the asymmetric unit that are similar in conformation. The cyanophenyl groups and the imidazole moieties in the CGS 18320B molecules display a propellor-like arrangement. The orientation of the imidazole ring in CGS 16949A, which is constrained by the piperidine ring, differs by about 80 degrees from the orientations in both CGS 18320B molecules. The conformations of both compounds are consistent with the proposed model (Banting et al. (1988) J. Enz. Inhibit., 2, 216) for inhibitor binding by positioning of the cyanophenyl group in the steroid A-ring binding site and interaction of the imidazole nitrogen with the iron of the haem.

Reversible inhibition of human placental microsomal aromatase by CGS 18320B and other non-steroidal compounds.

The effect of bis-(p-cyanophenyl)imidazo-1-yl-methane hemisuccinate (CGS 18320B) and other non-steroidal compounds on the aromatization of androstenedione by human placental microsomal aromatase was studied. CGS 18320B exhibited competitive inhibition with an apparent Ki of 0.16 nM, a 90 and 3800-fold increase in affinity compared to 4-hydroxyandrostenedione and amino-glutethimide, respectively. The inhibition is not time-dependent, indicating that the active site interaction is reversible. CGS 18230B showed a two-fold increased affinity as compared to 4-(5,6,7,8-tetrahydroimidazo[1,5a]pyridin-5-yl)benzonitrile (CGS 16949A) and cis-1-[(4-[(1-imidazoyl)methyl]cyclohexyl)methyl]-imidazole succinate (CGS 14796C) which showed Ki values of 0.35 and 0.39 4M, respectively. 1-[2-[1-(4-carboxyphenyl)-3-ureido]ethyl]-2-(4-pyridyl)-2-imidazoline monohydrochloride (CGP 15720A) showed negligible inhibition.