Hydrogen-bonded aggregations of oxo-cholic acids

Abstract

The crystal structures of six new crystals of oxo-cholic acids (oxo-CA) are reported: (I) 3alpha,12alpha-dihydroxy-7-oxo-5beta-cholan-24-oic acid; (II) 3alpha,7alpha-dihydroxy-12-oxo-5beta-cholan-24-oic acid; (III) 7alpha-hydroxy-3,12-dioxo-5beta-cholan-24-oic acid; (IV-alpha) and (IV-beta) 12alpha-hydroxy-3,7-dioxo-5beta-cholan-24-oic acid; (V) 3,7,12-trihydroxy-5beta-cholan-24-oic acid. (IV-beta) is a pseudopolymorphic solvated form of (IV-alpha) and contains small channels which can trap disordered water molecules. In all the structures the four saturated cycles, forming the common alicyclic skeleton, have the same conformation, while the carboxylic side chain adopts flexible conformations in order to produce the most efficient crystal aggregations. The structures display a variety of supramolecular architectures dominated by networks of cooperative O-H...O hydrogen bonds forming different packing motifs often supported by weaker C-H...O interactions.

Determination of critical micellar concentrations of two monoketo derivatives of cholic acid

“…7A). However, in the molecule of 12-MKC the C12 keto group, via water molecule, forms a hydrogen bond with the hydroxyl group of the side chain since the keto group is shifted towards the ␤ side [34]. This is in contrast to the molecule of 7-MKC, in which, the C12-OH group cannot form a hydrogen bond with the side chain.…”

Inclusion Compounds of Dehydrocholic Acid with Solvents

“…The guest acetone could be quantitatively removed from the structure by heating under vacuum at 140 °C to form 1 in the polymorphic α-form. The X-ray structure previously obtained for 1 put in evidence the absence of channels which characterize the crystal structure of many steroid compounds [ 5a,b ]; consequently this form of 1 must have high flexibility to alter its structure to accommodate guest species. Following these findings we have prepared inclusion compounds of dehydrocholic acid with a variety of organic solvents, that accommodate within 1 in assemblies of variable host:guest ratio as shown in Table 1 .…”

“…In most cases, as for example for cholic, deoxycholic, chenodeoxycholic, amide derivatives and norbile acids, the inclusion aptitude of host molecules has been confirmed in the crystalline state [ 1 ]. In recent years we have studied the inclusion ability of dehydrocholic acid 1 for the resolution of organic racemates [ 2 ] of aryl methyl sulfoxides [ 3 ] and cyclic amides [ 4 ], including the precise definition of the different structures involving the sole host or the host-guest assemblies [ 5 ].…”

Cholesterol solubilization by oxo derivatives of selected bile acids and their membranotoxicity

“…This difference is the consequence of the shielding of C12 oxo group with the side chain 13 (formation of a hydrogen bond between C12 oxo and side-chain COOH hydroxy groups, or alternatively, among C12 oxo group, water and side-chain COO -group if the COOH group is deprotonated). Bertolesi et al 34 found the hydrogen bond between the side chain and the C12 oxo group of the dehydrocholic acid (13). Due to this shielding, 12-oxolithocholic acid (4) is more hydrophobic than 7-oxolithocholic (5) or hyodeoxycholic (3) acid (R M0 retention index in the reverse thin layer chromatography, molecular lipophilicity, for the 12-oxoLC is 4.68 while for the 7-oxoLC 4.49) 28 .…”