Structure of Equilenin at 100 K: an estrone-related steroid

The structure of the estrone-related steroid, Equilenin, C18H18O2 (systematic name 3-hy-droxy-13-methyl-11,12,13,14,15,16-hexa-hydro-cyclo-penta-[a]phen-anthren-17-one), has been determined at 100 K. The crystals are ortho-rhom-bic, P212121, and the absolute structure of the mol-ecule in the crystal has been determined by resonant scattering [Flack parameter = -0.05 (4)]. The C atoms of the A and B rings are almost coplanar, with an r.m.s. deviation from planarity of 0.0104 Å. The C ring has a sofa conformation, while the D ring has an envelope conformation with the methine C atom as the flap. The keto O atom and the methyl group are translated 0.78 and 0.79 Å, respectively, from the equivalent positions on 17β-estrone. In the crystal, mol-ecules are linked by O-H⋯O hydrogen bonds, forming chains parallel to the c-axis direction

Engineering robust polar chiral clathrate crystals

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ Royal Society of Chemistry 2013.The R-(+)-enantiomeric form of Dianin's compound and the S-(+)-enantiomeric form of its direct thiachroman analogue both obtained chromatographically employing a cellulose tris(3,5-dimethylphenylcarbamate) column, are shown to undergo supramolecular assembly to form a polar clathrate lattice which is stable even in the absence of a consolidating guest component

International genome-wide meta-analysis identifies new primary biliary cirrhosis risk loci and targetable pathogenic pathways.

Primary biliary cirrhosis (PBC) is a classical autoimmune liver disease for which effective immunomodulatory therapy is lacking. Here we perform meta-analyses of discovery data sets from genome-wide association studies of European subjects (n=2,764 cases and 10,475 controls) followed by validation genotyping in an independent cohort (n=3,716 cases and 4,261 controls). We discover and validate six previously unknown risk loci for PBC (Pcombined<5 × 10(-8)) and used pathway analysis to identify JAK-STAT/IL12/IL27 signalling and cytokine-cytokine pathways, for which relevant therapies exist

Cyclodextrins as chiral nuclear magnetic resonance shift reagents

Although chemical shift non-equivalence between enantiotopic groups in n.m.r. spectra has often been observed employing optically active solvents or chiral lanthanide shift reagents, or when a substrate is complexed to a chiral crown compound, such methods are normally critically dependent upon suitable substrate functionality. We now report that guest binding within the chiral cavity of β-cyclodextrin in D2O provides a method for inducing 19F n.m.r. chemical shifts between the prochiral CF3 groups of compounds 1 [1,1,1,3,3,3-hexafluoro-2-phenyl-2-propanol] and 2 [1,1,1,3,3,3-hexafluoro-2-(p-tolyl)propane], it being particularly noteworthy that the latter molecule lacks the type of functional group usually required for such chiral effects

Internal rotation in a guest molecule complexed with <i>β</i>-cyclodextrin in deuterium oxide solution

The cyclodextrins have attracted much attention as enzyme active-site models. These torus-shaped molecules, possessing a central lipophilic cavity for guest inclusion, are made up of α-1,4-linked D-glucopyranose units, α-, β-, and γ-cyclodextrin (α-, β-, and γ-CD) comprising 6, 7, and 8 units, respectively. We now report the first example of the catalysis of a degenerate exchange process for a molecule accommodated in a cyclodextrin void. Internal rotation in N,N-dimethyl-p-nitrobenzamide (I) complexed by β-CD in D2O was selected for detailed study

Synthesis and crystal structure of 2,4,6,8-tetrakis(3,5-di-tert-butylphenoxy)pyrimido[5,4-d]pyrimidine: expansion of the Piedfort concept

The title host compound, C62H84N4O4, designed to self-assemble to form a new type of extended core Piedfort unit reminiscent of an eight-legged spider host, forms a number of crystalline inclusion compounds favouring oxygen-containing guest molecules. We have established the presence of this unit in the unsolvated molecular crystal at 100 K, which is monoclinic, space group P21/n, with Z = 8. The new Piedfort unit is chiral and its core structure closely approximates to D2 symmetry, with both enantiomers present in the crystal. Rather than being superposed with a staggered arrangement of nitrogen atoms, the rings are rotated by an angle of approximately 45° with respect to each other, and the shortest contact between them is 3.181 (2) Å. The compound's significant inclusion properties may be taken to suggest the participation of an extended Piedfort unit in the microcrystalline adducts formed. The presence of such a dimeric host unit in the clathrates has, however, not yet been established because of the current lack of suitable single crystals for X-ray analysis