(3R,6S,7aS)-3-Phenyl-6-(phenyl­sulfan­yl)perhydro­pyrrolo[1,2-c]oxazol-5-one

Mol­ecules of the title compound [systematic name: (2R,5S,7S)-2-phenyl-7-phenyl­sulfanyl-1-aza-3-oxa­bicyclo­[3.3.0]octan-8-one], C18H17NO2S, form high quality crystals even though they are only packed using C—H⋯O(carbon­yl) and weak C—H⋯S inter­actions. The dihedral angle between the aromatic rings is 85.53 (5)°. The fused rings adopt envelope and twist conformations

(9H-Fluoren-9-yl)methyl N-{(2R,3R,4S)-4-hy­droxy-2-[(2S,5R)-2-isopropyl-5-methyl­cyclo­hex­yloxy]-5-oxooxolan-3-yl}carbamate propan-2-ol 0.334-solvate

The title compound, C29H35NO6.0.334C3H8O, a novel chiral N-(fluoren-9-yl­methyl­oxyxcarbon­yl) precursor, crystallizes with two independent carbamate (M) mol­ecules and propan-2-ol solvent mol­ecules in the unit cell. Its crystal structure has been determined from barely adequate data obtained from a multi-fragment needle crystal. In the crystal, N—H⋯O hydrogen bonds link M mol­ecules related by translation along the a axis into two independent chains. The ordered solvent mol­ecule, having a partial occupancy of 0.334, is attached to one independent M mol­ecule through O—H⋯O hydrogen bonds. The crystal packing exhibits weak inter­molecular C—H⋯O inter­actions and voids of 270 Å3 filled with randomly disordered solvent mol­ecules which were handled using the SQUEEZE methodology

Synthesis of Novel C/D Ring Modified Bile Acids

Bile acid receptors have been identified as important targets for the development of new therapeutics to treat various metabolic and inflammatory diseases. The synthesis of new bile acid analogues can help elucidate structure–activity relationships and define compounds that activate these receptors selectively. Towards this, access to large quantities of a chenodeoxycholic acid derivative bearing a C-12 methyl and a C-13 to C-14 double bond provided an interesting scaffold to investigate the chemical manipulation of the C/D ring junction in bile acids. The reactivity of this alkene substrate with various zinc carbenoid species showed that those generated using the Furukawa methodology achieved selective α-cyclopropanation, whereas those generated using the Shi methodology reacted in an unexpected manner giving rise to a rearranged skeleton whereby the C ring has undergone contraction to form a novel spiro–furan ring system. Further derivatization of the cyclopropanated steroid included O-7 oxidation and epimerization to afford new bile acid derivatives for biological evaluation

Synthesis of Novel C/D Ring Modified Bile Acids

Bile acid receptors have been identified as important targets for the development of new therapeutics to treat various metabolic and inflammatory diseases. The synthesis of new bile acid analogues can help elucidate structure–activity relationships and define compounds that activate these receptors selectively. Towards this, access to large quantities of a chenodeoxycholic acid derivative bearing a C-12 methyl and a C-13 to C-14 double bond provided an interesting scaffold to investigate the chemical manipulation of the C/D ring junction in bile acids. The reactivity of this alkene substrate with various zinc carbenoid species showed that those generated using the Furukawa methodology achieved selective α-cyclopropanation, whereas those generated using the Shi methodology reacted in an unexpected manner giving rise to a rearranged skeleton whereby the C ring has undergone contraction to form a novel spiro–furan ring system. Further derivatization of the cyclopropanated steroid included O-7 oxidation and epimerization to afford new bile acid derivatives for biological evaluation

Design, Synthesis and Biological Evaluation of Isoxazole-Based CK1 Inhibitors Modified with Chiral Pyrrolidine Scaffolds

In this study, we report on the modification of a 3,4-diaryl-isoxazole-based CK1 inhibitor with chiral pyrrolidine scaffolds to develop potent and selective CK1 inhibitors. The pharmacophore of the lead structure was extended towards the ribose pocket of the adenosine triphosphate (ATP) binding site driven by structure-based drug design. For an upscale compatible multigram synthesis of the functionalized pyrrolidine scaffolds, we used a chiral pool synthetic route starting from methionine. Biological evaluation of key compounds in kinase and cellular assays revealed significant effects of the scaffolds towards activity and selectivity, however, the absolute configuration of the chiral moieties only exhibited a limited effect on inhibitory activity. X-ray crystallographic analysis of ligand-CK1δ complexes confirmed the expected binding mode of the 3,4-diaryl-isoxazole inhibitors. Surprisingly, the original compounds underwent spontaneous Pictet-Spengler cyclization with traces of formaldehyde during the co-crystallization process to form highly potent new ligands. Our data suggests chiral “ribose-like” pyrrolidine scaffolds have interesting potential for modifications of pharmacologically active compounds

Synthesis of 12β-methyl-18-nor-avicholic acid analogues as potential TGR5 agonists

In the quest for new modulators of the Farnesoid-X (FXR) and Takeda G-protein-coupled (TGR5) receptors, bile acids are a popular candidate for drug development. Recently, bile acids endowed with a C16-hydroxy group emerged as ligands of FXR and TGR5 with remarkable agonistic efficacies. Inspired by these findings, we synthesised a series of C16-hydroxylated 12β-methyl-18-nor-bile acid analogues from a Δ13(17)-12β-methyl-18-nor-chenodeoxycholic acid intermediate (16), the synthesis of which we reported previously. The preparation of these aptly named 12β-methyl-18-nor-avicholic acids (17, 18, 41 and 42) was accomplished via allylic oxidation at C16, hydrogenation of the C13→C17 double bond and selective reduction of the C16-carbonyl group. Described also are various side products which were isolated during the evaluation of methods to affect the initial allylic oxidation. In addition, C23-methyl modified 12β-methyl-18-nor-bile acids with (48, 49, 51 and 52) and without a C16-hydroxy group (45, 46 and 55), were synthesized to enable comparison of biological activities between these compounds and their un-methylated counterparts. As a result of our investigations we identified (23R)-12β,23-dimethyl-18-nor-chenodeoxycholic acid (46) and 12β-methyl-17-epi-18-nor-chenodeoxycholic acid 53 as TGR5 ligands with EC50 values of 25 μM